Summary
# Stable angina and coronary artery disease
Stable angina is a symptom of coronary artery disease characterized by chest pain due to a fixed atherosclerotic lesion that narrows the coronary arteries, leading to ischemia when oxygen demand exceeds supply, typically during exertion or stress [2](#page=2).
## 1. Stable angina and coronary artery disease
### 1.1 Definition
Stable angina occurs when a fixed atherosclerotic lesion narrows the coronary arteries, causing myocardial ischemia when the heart's oxygen demand outstrips supply. This imbalance is typically triggered by exertion or emotional stress [2](#page=2).
### 1.2 Major risk factors
The major risk factors for coronary artery disease (CAD) and stable angina include:
* Diabetes mellitus (considered the worst risk factor) [2](#page=2).
* Hypertension (the most common risk factor) [2](#page=2).
* Hyperlipidemia, specifically elevated LDL cholesterol and low HDL cholesterol [2](#page=2).
* Cigarette smoking [2](#page=2).
* Age: men over 45 years and women over 55 years [2](#page=2).
* Family history of premature CAD or myocardial infarction (MI) [2](#page=2).
* Other factors include end-stage renal disease (ESRD) on dialysis, HIV, mediastinal radiation, obesity, sedentary lifestyle, stress, and excess alcohol consumption [2](#page=2).
### 1.3 Prognosis indicators
Prognosis in patients with stable angina is influenced by:
* **Left ventricular function:** An ejection fraction (EF) greater than 50% indicates a better prognosis, while an EF less than 50% is associated with increased mortality [2](#page=2).
* **Extent of vessel disease:** Left main CAD has a poor prognosis due to its supply of approximately two-thirds of the left ventricle (LV). Two- or three-vessel CAD generally carries a worse prognosis than single-vessel disease [2](#page=2).
### 1.4 Clinical features of stable angina
Patients typically present with:
* Substernal or heavy, pressure-like chest pain [2](#page=2).
* Pain that lasts for 1 to 15 minutes, with a gradual onset [2](#page=2).
* Triggers include exertion, emotion, cold exposure, and stimulant drugs like cocaine or methamphetamine [2](#page=2).
* Relief is usually achieved with rest or nitroglycerin [2](#page=2).
* The pain is not pleuritic, positional, or reproducible by palpation [2](#page=2).
> **Tip:** If chest pain lasts for 20-30 minutes, consider acute MI rather than stable angina [2](#page=2).
### 1.5 Diagnosis
* **Physical exam:** The physical examination is often normal between angina episodes. Clues may include signs of hypertension, peripheral vascular disease, or less commonly, xanthelasma [2](#page=2).
* **Resting ECG:** A resting ECG is frequently normal in stable angina. However, Q waves may indicate a prior MI. ST-segment or T-wave changes during an episode are consistent with ischemia [2](#page=2).
* **Stress testing:** This is used for patients with intermediate pre-test probability of CAD.
* **Exercise ECG:** May reveal ST-segment depression [2](#page=2).
* **Stress echocardiogram:** Can identify new wall motion abnormalities [2](#page=2).
* **Nuclear perfusion imaging (e.g., thallium, technetium):** Shows decreased isotope uptake in ischemic areas, indicating relative underperfusion when the coronary arteries are maximally dilated [2](#page=2).
* **Pharmacologic stress testing:** Used when patients cannot exercise. Agents like adenosine or dipyridamole cause vasodilation, while dobutamine increases heart rate, blood pressure, and contractility. These are used with perfusion imaging or stress echocardiography [2](#page=2).
* **Coronary angiography:** This is the gold standard for visualizing CAD anatomy, including the presence, location, and severity of stenosis. It is indicated after a positive stress test or a high-risk presentation. Significant stenosis is usually defined as greater than 70% luminal narrowing [2](#page=2).
### 1.6 Risk factor modification
Comprehensive management includes modifying risk factors:
* **Smoking cessation:** Risk decreases by 50% after one year of quitting [2](#page=2).
* **Blood pressure control:** Especially crucial in diabetic patients [2](#page=2).
* **Hyperlipidemia treatment:** Statins are primary, aiming for LDL less than 70 mg/dL in patients with known CAD [2](#page=2).
* **Glycemic control:** Tight control of blood sugar in diabetes is essential, as cardiovascular disease is considered a "diabetes equivalent" [2](#page=2).
* **Weight loss:** Recommended for obese individuals [2](#page=2).
* **Regular exercise:** Promotes cardiovascular health [2](#page=2).
* **Diet:** A heart-healthy diet low in saturated fat and cholesterol is advised [2](#page=2).
### 1.7 Medical therapy
Medical therapy aims to reduce mortality and relieve symptoms.
* **Mortality benefit:**
* Aspirin is recommended for all patients with CAD to reduce MI risk [2](#page=2).
* High-intensity statins, potentially with PCSK9 inhibitors, are crucial for lipid management [2](#page=2).
* Beta-blockers reduce heart rate, blood pressure, and contractility, thereby decreasing myocardial oxygen demand [2](#page=2).
* **Symptom relief:**
* Beta-blockers are used for their hemodynamic effects [2](#page=2).
* Nitrates provide relief through venodilation, reducing preload and myocardial oxygen demand. They can be administered via various routes [2](#page=2).
* Calcium channel blockers (CCBs) cause vasodilation and reduce afterload [2](#page=2).
* Ranolazine can be used as an add-on antianginal agent [2](#page=2).
> **Key side effects:** Beta-blockers can cause erectile dysfunction and limit exercise response. Nitrates may lead to headache, orthostatic hypotension, tolerance, and syncope. CCBs should be used cautiously in patients with low EF [2](#page=2).
### 1.8 Revascularization (Stable CAD)
Revascularization procedures are considered when medical therapy is insufficient or in cases of high-risk anatomy.
* **Methods:**
* **Percutaneous Coronary Intervention (PCI):** Involves angioplasty with or without stent placement to open blocked arteries [2](#page=2).
* **Coronary Artery Bypass Grafting (CABG):** A surgical procedure using grafts (e.g., LIMA, saphenous vein) to bypass blocked sections of coronary arteries, creating new pathways for blood flow [2](#page=2).
* **General use:** Primarily for symptom control when medical therapy fails. Indicated for high-risk anatomy such as left main disease, three-vessel disease, or disease involving the left anterior descending (LAD) artery in conjunction with reduced LV function [2](#page=2).
* **Severity-based approach:**
* **Mild CAD:** Normal EF, mild angina, single-vessel disease is typically managed with medications (nitrates and beta-blockers, possibly CCBs) [2](#page=2).
* **Moderate CAD:** Normal EF, moderate angina, two-vessel disease may warrant consideration for angiography to evaluate for PCI or CABG [2](#page=2).
* **Severe CAD:** Reduced EF, severe angina, left main disease, or three-vessel disease involving the LAD suggests significant risk and requires angiography with consideration for CABG. CCBs should be avoided in patients with low EF [2](#page=2).
---
# Unstable angina and acute coronary syndromes
Unstable angina is a critical component of acute coronary syndromes, characterized by plaque rupture and thrombosis, necessitating prompt and aggressive management [3](#page=3).
### 2.1 Pathophysiology of unstable angina
In unstable angina, the oxygen demand of the myocardium remains unchanged, but there is a decrease in resting coronary blood flow. This reduction in flow is primarily due to [3](#page=3):
* Enlargement of an existing atherosclerotic plaque [3](#page=3).
* Thrombosis or hemorrhage within the plaque [3](#page=3).
* Plaque rupture, which can lead to partial or complete occlusion of the coronary artery [3](#page=3).
### 2.2 Clinical definition of unstable angina
Unstable angina is defined by a worsening pattern of chronic angina or the new onset of severe angina. This includes:
* An increase in the frequency, duration, or intensity of previously stable angina [3](#page=3).
* The onset of new, severe angina that was not present before [3](#page=3).
* Angina occurring at rest [3](#page=3).
### 2.3 Relation to NSTEMI and ACS
Unstable angina (UA) is a part of the spectrum of conditions known as acute coronary syndromes (ACS) [3](#page=3).
* **UA vs. NSTEMI:** Both unstable angina and Non-ST-Elevation Myocardial Infarction (NSTEMI) share similarities in that they do not present with ST-segment elevation on an electrocardiogram (ECG) and do not show pathologic Q waves. The primary distinction lies in cardiac enzymes: UA is characterized by normal cardiac enzymes, while NSTEMI shows elevated troponin or CK-MB levels [3](#page=3).
* **Acute Coronary Syndrome (ACS):** ACS encompasses unstable angina, NSTEMI, and ST-Elevation Myocardial Infarction (STEMI). It is treated as a medical emergency [3](#page=3).
### 2.4 Diagnosis
The diagnostic workup for unstable angina is similar to that for stable angina. However, it is crucial to always exclude myocardial infarction (MI) by performing serial ECGs and enzyme measurements. Stress testing in patients with suspected unstable angina carries a higher risk and should be preceded by stabilization of the patient's condition or immediate cardiac catheterization [3](#page=3).
### 2.5 Initial management of unstable angina
Initial management focuses on prompt stabilization and monitoring:
* Hospital admission with continuous cardiac monitoring [3](#page=3).
* Establishment of intravenous (IV) access [3](#page=3).
* Administration of oxygen if the patient is hypoxic [3](#page=3).
* Analgesia to relieve chest pain, with nitrates as the first-line treatment and opioids used if pain persists [3](#page=3).
### 2.6 Medical therapy for unstable angina
Patients with unstable angina are treated similarly to those with MI, with the exception that fibrinolysis (clot-busting therapy) is **not** indicated for UA or NSTEMI. Treatment includes [3](#page=3):
* **Antiplatelet therapy:** This is essential and should be initiated as soon as possible. It includes Aspirin 325 mg and a P2Y₁₂ inhibitor (e.g., clopidogrel, ticagrelor, or prasugrel). Dual antiplatelet therapy (DAPT) is generally continued for 9-12 months [3](#page=3).
* **Anticoagulation:** Low molecular weight heparin (LMWH) is preferred over unfractionated heparin (UFH). Enoxaparin is often preferred due to demonstrated benefits in reducing the incidence of death, MI, or recurrent angina requiring revascularization (as shown in the ESSENCE trial). The goal is to prevent clot progression or new clot formation over approximately 48 hours [3](#page=3).
* **Beta-blockers:** These are administered if there are no contraindications, as they help reduce myocardial oxygen demand by decreasing heart rate and contractility, and also reduce arrhythmia risk [3](#page=3).
* **Nitrates:** These are the first-line treatment for ischemic chest pain, working by reducing preload and improving coronary blood flow supply/demand balance [3](#page=3).
* **High-intensity statin therapy:** For example, atorvastatin 40-80 mg is recommended. Statin therapy is beneficial for all patients with coronary artery disease (CAD) [3](#page=3).
* **GP IIb/IIIa inhibitors:** Medications like abciximab or tirofiban may be used if the patient is undergoing percutaneous coronary intervention (PCI) [3](#page=3).
* **Oxygen:** Administered if the patient is hypoxic [3](#page=3).
* **Morphine:** Used for symptom relief and anxiety control, though its use is somewhat controversial and it may mask worsening symptoms or cause hypotension [3](#page=3).
* **Electrolyte correction:** Potassium (K⁺) and magnesium (Mg²⁺) levels should be corrected to prevent arrhythmias [3](#page=3).
### 2.7 Revascularization strategy
Most patients (over 90%) show improvement within 1-2 days of medical therapy. The decision between an early invasive versus a conservative approach is often guided by risk stratification scores, such as the TIMI score [3](#page=3).
* If symptoms or ECG changes persist beyond 48 hours, cardiac catheterization followed by PCI or coronary artery bypass grafting (CABG) is indicated [3](#page=3).
* Indications for PCI include ongoing instability, the presence of ventricular arrhythmias, or the development of new mitral regurgitation or a septal defect. These conditions suggest unstable blood flow or hemodynamic compromise [3](#page=3).
### 2.8 Post-acute long-term care
Long-term management aims to prevent future events and modify risk factors:
* **Continued medical therapy:** Patients should continue Aspirin and a P2Y₁₂ inhibitor (DAPT), a beta-blocker (e.g., metoprolol), nitrates as needed (PRN), and statin therapy [3](#page=3).
* **Risk factor modification:** This includes smoking cessation, weight loss, control of diabetes and hypertension, and treatment of hyperlipidemia with statins for all patients with CAD [3](#page=3).
### 2.9 Variant (Prinzmetal's) Angina
Variant angina, also known as Prinzmetal's angina, is a different form of angina characterized by transient coronary vasospasm [3](#page=3).
* **Pathophysiology:** It often occurs in the presence of an underlying atherosclerotic lesion but can also affect normal coronary arteries [3](#page=3).
* **Clinical Features:** Angina typically occurs at rest, often at night, and episodes can be life-threatening, potentially associated with ventricular arrhythmias. Between attacks, the ECG can be normal [3](#page=3).
* **ECG:** During episodes of pain, transient ST-segment elevation may be observed, representing transmural ischemia [3](#page=3).
* **Diagnosis:** This is usually made through coronary angiography, where vasospasm can be provoked by ergonovine or acetylcholine [3](#page=3).
* **Treatment:** Management primarily involves calcium channel blockers (CCBs) and nitrates. Risk factor modification, particularly smoking cessation and lipid lowering, is also important [3](#page=3).
---
# Myocardial infarction (MI) and its complications
This section details the definition, causes, clinical presentation, diagnostic methods, treatment strategies, and common complications of myocardial infarction [4](#page=4) [5](#page=5) [6](#page=6).
### 3.1 General characteristics of myocardial infarction
Myocardial infarction (MI) is defined as the necrosis of heart muscle tissue due to an acute interruption of coronary blood flow. The usual cause is the thrombotic occlusion of a coronary artery, typically occurring over a ruptured atherosclerotic plaque [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.1.1 Epidemiologic pearls and risk factors
Approximately 30% of MIs result in mortality, with about 50% of these deaths occurring pre-hospital, often due to ventricular tachycardia (VT) or ventricular fibrillation (VF). Many patients have a history of angina, coronary artery disease (CAD) risk factors, or prior arrhythmias. Major risk factors for CAD include [4](#page=4) [5](#page=5) [6](#page=6):
* Diabetes mellitus [4](#page=4) [5](#page=5) [6](#page=6).
* Hyperlipidemia (low-density lipoprotein [ˢLDL, high-density lipoprotein [ˣHDL]) [4](#page=4) [5](#page=5) [6](#page=6).
* Hypertension [4](#page=4) [5](#page=5) [6](#page=6).
* Cigarette smoking [4](#page=4) [5](#page=5) [6](#page=6).
* Age (men >45 years, women >55 years) [4](#page=4) [5](#page=5) [6](#page=6).
* Family history of premature CAD or MI [4](#page=4) [5](#page=5) [6](#page=6).
### 3.2 Clinical features of myocardial infarction
#### 3.2.1 Chest pain
The characteristic chest pain is an intense substernal pressure, often described as "crushing" or an "elephant on the chest". It may radiate to the neck, jaw, arms (usually the left), or back. While similar in location to angina, MI pain is typically more severe, lasts longer than 30 minutes, and is often not relieved by nitroglycerin. Some patients may present with epigastric discomfort [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.2.2 Asymptomatic or atypical presentations
Up to one-third of MIs can be asymptomatic or present atypically, particularly in the elderly, diabetic patients, postoperative individuals, and women. These are often referred to as "silent" MIs [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.2.3 Other symptoms
Associated symptoms can include dyspnea, diaphoresis, weakness, fatigue, nausea, vomiting, a sense of impending doom, and syncope [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.2.4 Sudden cardiac death
Sudden cardiac death in the context of MI is usually due to ventricular fibrillation (VF) or sustained VT, particularly in the early phase [4](#page=4) [5](#page=5) [6](#page=6).
### 3.3 Diagnosis of myocardial infarction
#### 3.3.1 Electrocardiogram (ECG)
The ECG is crucial for identifying markers of ischemia, injury, and infarction [4](#page=4) [5](#page=5) [6](#page=6).
* **Ischemia/Injury/Infarction Markers:**
* Peaked T waves: very early ischemia [4](#page=4) [5](#page=5) [6](#page=6).
* ST elevation: indicates transmural injury and is diagnostic of acute ST-segment elevation MI (STEMI) [4](#page=4) [5](#page=5) [6](#page=6).
* ST depression: suggests subendocardial ischemia, often seen in non-ST-segment elevation MI (NSTEMI) or unstable angina (UA) [4](#page=4) [5](#page=5) [6](#page=6).
* Q waves: a late sign of necrosis [4](#page=4) [5](#page=5) [6](#page=6).
* T-wave inversion: sensitive but not specific for ischemia [4](#page=4) [5](#page=5) [6](#page=6).
* **Categories of MI:**
* **ST-segment elevation MI (STEMI):** Characterized by transmural injury, with ST elevation that may progress to Q waves [4](#page=4) [5](#page=5) [6](#page=6).
* **Non-ST-segment elevation MI (NSTEMI):** Involves subendocardial injury, presenting with ST depression or T-wave changes but no ST elevation [4](#page=4) [5](#page=5) [6](#page=6).
* **Location by Leads:**
* **Anterior (LAD):** ST elevation/Q waves in V1–V4 [4](#page=4) [5](#page=5) [6](#page=6).
* **Posterior:** Large R wave and ST depression in V1–V2 [4](#page=4) [5](#page=5) [6](#page=6).
* **Lateral (LCx):** Changes in leads I, aVL, and potentially V5–V6 [4](#page=4) [5](#page=5) [6](#page=6).
* **Inferior (RCA):** Changes in leads II, III, aVF [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.3.2 Cardiac enzymes
Cardiac enzymes are released into the bloodstream following myocardial cell death.
* **Troponin I / T (gold standard):**
* Rise: 3–5 hours after onset [4](#page=4) [5](#page=5) [6](#page=6).
* Peak: 24–48 hours [4](#page=4) [5](#page=5) [6](#page=6).
* Duration: 5–14 days. Elevated troponin levels are good for diagnosis but poor for detecting reinfarction. A higher peak and longer elevation indicate a worse prognosis [4](#page=4) [5](#page=5) [6](#page=6).
* **CK-MB (Creatine Kinase-Myocardial Band):**
* Rise: 4–8 hours after onset [4](#page=4) [5](#page=5) [6](#page=6).
* Peak: approximately 24 hours [4](#page=4) [5](#page=5) [6](#page=6).
* Normal: 48–72 hours. CK-MB is better for detecting recurrent MIs, especially if troponin is still elevated from a previous event [4](#page=4) [5](#page=5) [6](#page=6).
* **Sampling Strategy:** Serial measurements of cardiac enzymes (on admission and every 6–8 hours) are recommended to observe the characteristic rise and fall pattern [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.3.3 Monitoring
Continuous monitoring is essential for patients with acute MI [4](#page=4) [5](#page=5) [6](#page=6).
* **Rhythm strip:** For detecting arrhythmias like premature ventricular contractions (PVCs), VT, and VF [4](#page=4) [5](#page=5) [6](#page=6).
* **Hemodynamics:** Monitor blood pressure and heart rate, as both hypotension and severe hypertension are detrimental. In unstable patients, invasive hemodynamic monitoring may be necessary to guide fluid management and inotropic support [4](#page=4) [5](#page=5) [6](#page=6).
* **Auscultation:** Listen for new murmurs, S3/S4 gallops, or rubs, as well as lung crackles indicative of pulmonary congestion [4](#page=4) [5](#page=5) [6](#page=6).
### 3.4 Treatment of acute MI
#### 3.4.1 Immediate general measures
* Admit to a coronary care unit (CCU) or a monitored setting [4](#page=4) [5](#page=5) [6](#page=6).
* Establish intravenous (IV) access [4](#page=4) [5](#page=5) [6](#page=6).
* Administer oxygen if the patient is hypoxic [4](#page=4) [5](#page=5) [6](#page=6).
* Provide analgesia, typically with nitrates, and morphine if pain persists [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.4.2 Medical therapy
Medical therapy aims to reduce mortality and manage symptoms.
* **Antiplatelet therapy:**
* Aspirin: Should be given to all patients as it reduces mortality and reinfarction rates and is typically lifelong [4](#page=4) [5](#page=5) [6](#page=6).
* P2Y12 inhibitor (e.g., clopidogrel, ticagrelor): Given in combination with aspirin (dual antiplatelet therapy, DAPT) [4](#page=4) [5](#page=5) [6](#page=6).
* **Anti-ischemic and remodeling agents:**
* Beta-blockers: Reduce heart rate, blood pressure, and contractility, thereby decreasing myocardial oxygen demand and arrhythmias [4](#page=4) [5](#page=5) [6](#page=6).
* ACE inhibitors: Should be started early to limit ventricular remodeling and reduce mortality. Start if no hypotension or renal artery stenosis [4](#page=4) [5](#page=5) [6](#page=6).
* High-intensity statin (e.g., atorvastatin 80 mg): Reduces future adverse events and stabilizes plaques [4](#page=4) [5](#page=5) [6](#page=6).
* **Anticoagulation:**
* Heparin (unfractionated heparin [UFH or low molecular weight heparin [LMWH, such as enoxaparin): Prevents thrombus propagation but is not directly mortality-reducing. Heparin is used for UA and MI, but not unstable angina [4](#page=4) [5](#page=5) [6](#page=6).
* **Symptomatic agents:**
* Nitrates: Cause vasodilation, reduce preload, and can relieve pain [4](#page=4) [5](#page=5) [6](#page=6).
* Morphine: Provides analgesia and venodilation, but should be used with caution [4](#page=4) [5](#page=5) [6](#page=6).
* Oxygen: Only if the patient is hypoxic [4](#page=4) [5](#page=5) [6](#page=6).
* **Discharge/Long-Term Essentials:** Patients should be discharged on aspirin, a P2Y12 inhibitor (if indicated), a beta-blocker, an ACE inhibitor, and a high-intensity statin [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.4.3 Revascularization
Revascularization aims to restore blood flow to the ischemic myocardium.
* **Percutaneous Coronary Intervention (PCI):**
* Preferred treatment for STEMI if door-to-balloon time is less than 90 minutes [4](#page=4) [5](#page=5) [6](#page=6).
* Associated with lower rates of recurrent MI and intracranial bleeding compared to thrombolysis [4](#page=4) [5](#page=5) [6](#page=6).
* Also used in high-risk UA/NSTEMI patients [4](#page=4) [5](#page=5) [6](#page=6).
* **Thrombolytic Therapy:**
* Indications: ST elevation in at least two contiguous leads with chest pain of less than approximately 6 hours duration and no contraindications [4](#page=4) [5](#page=5) [6](#page=6).
* Agents: Alteplase (tPA), streptokinase, tenecteplase, etc. [4](#page=4) [5](#page=5) [6](#page=6).
* Absolute contraindications: Recent head trauma or cardiopulmonary resuscitation, prior stroke, recent surgery, aortic dissection, active bleeding, etc. [4](#page=4) [5](#page=5) [6](#page=6).
* **Coronary Artery Bypass Grafting (CABG):**
* Considered for patients with mechanical complications, cardiogenic shock, failed PCI, or complex multivessel or left main coronary artery disease [4](#page=4) [5](#page=5) [6](#page=6).
* Less commonly performed in the acute phase but can be beneficial long-term in selected patients. It is reserved for specific situations and is less used acutely than PCI. CABG shows better survival in many studies [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.4.4 Rehabilitation
Cardiac rehabilitation involves a structured exercise program and patient education. It also emphasizes risk factor modification (smoking cessation, weight management, blood pressure, lipid, and diabetes control). Participation in cardiac rehab has been shown to reduce symptoms and prolong survival [4](#page=4) [5](#page=5) [6](#page=6).
### 3.5 Complications of acute MI
#### 3.5.1 Pump failure
* **Congestive Heart Failure (CHF):** The most common in-hospital cause of death following MI. Mild CHF is managed with ACE inhibitors, diuretics, and standard heart failure regimens. Severe cases may progress to cardiogenic shock, requiring inotropes, invasive monitoring, and potentially mechanical support. Pulmonary edema can occur [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.5.2 Arrhythmias
A wide range of arrhythmias can occur post-MI:
* **PVCs (Premature Ventricular Contractions):** Usually benign; observation is typically sufficient [4](#page=4) [5](#page=5) [6](#page=6).
* **Atrial Fibrillation (AFib):** Managed with rate control and potentially anticoagulation [4](#page=4) [5](#page=5) [6](#page=6).
* **Ventricular Tachycardia (VT):** Unstable VT requires synchronized cardioversion; stable VT is treated with antiarrhythmics [4](#page=4) [5](#page=5) [6](#page=6).
* **Ventricular Fibrillation (VF):** Requires immediate unsynchronized defibrillation and cardiopulmonary resuscitation (CPR) [4](#page=4) [5](#page=5) [6](#page=6).
* **Accelerated Idioventricular Rhythm:** Typically benign and requires no specific therapy [4](#page=4) [5](#page=5) [6](#page=6).
* **Paroxysmal Supraventricular Tachycardia (PSVT):** Treated according to standard SVT protocols [4](#page=4) [5](#page=5) [6](#page=6).
* **Sinus Tachycardia:** Treat the underlying cause, such as pain, fever, or heart failure [4](#page=4) [5](#page=5) [6](#page=6).
* **Sinus Bradycardia:** Common in inferior MIs; treated only if symptomatic, using atropine and potentially pacing [4](#page=4) [5](#page=5) [6](#page=6).
* **Asystole:** Managed as part of arrest protocols; consider pacing [4](#page=4) [5](#page=5) [6](#page=6).
* **AV Block:**
* First-degree or Mobitz I: Often transient, requiring no specific therapy [4](#page=4) [5](#page=5) [6](#page=6).
* Mobitz II or third-degree (especially with anterior MI): May require a temporary pacemaker and chronotropic support [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.5.3 Recurrent infarction
* This can occur as an extension of the existing infarct or a new infarct, leading to increased short- and long-term mortality [4](#page=4) [5](#page=5) [6](#page=6).
* While troponin levels may still be elevated from the initial MI, an increase in CK-MB after 36–48 hours can help detect a new infarct [4](#page=4) [5](#page=5) [6](#page=6).
* Management includes repeat thrombolysis or urgent PCI, along with a full MI treatment regimen [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.5.4 Mechanical complications
These are serious and often life-threatening complications:
* **Free wall rupture:** Leads to cardiac tamponade and pulseless electrical activity (PEA) arrest; it has a high mortality and requires emergent surgery [4](#page=4) [5](#page=5) [6](#page=6).
* **Ventricular septal rupture:** Results in an acute ventricular septal defect (VSD) with subsequent heart failure or shock; urgent surgical repair is necessary [4](#page=4) [5](#page=5) [6](#page=6).
* **Papillary muscle rupture:** Causes acute severe mitral regurgitation (MR); diagnosis is aided by echocardiography, and emergent valve surgery is required [4](#page=4) [5](#page=5) [6](#page=6).
* **Ventricular pseudoaneurysm:** A contained rupture with a high risk of subsequent rupture; surgical repair is indicated [4](#page=4) [5](#page=5) [6](#page=6).
* **True ventricular aneurysm:** A scarred outpouching of the ventricle; it rarely ruptures but can lead to heart failure, arrhythmias, and thrombus formation [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.5.5 Acute pericarditis
* This can occur early after an MI [4](#page=4) [5](#page=5) [6](#page=6).
* Treatment involves aspirin, which is already a standard part of MI management [4](#page=4) [5](#page=5) [6](#page=6).
* Non-steroidal anti-inflammatory drugs (NSAIDs) and steroids should be avoided as they may impair myocardial scar formation [4](#page=4) [5](#page=5) [6](#page=6).
#### 3.5.6 Dressler syndrome
* Also known as post-MI syndrome, this is an autoimmune phenomenon occurring weeks to months after an MI [4](#page=4) [5](#page=5) [6](#page=6).
* Features include fever, malaise, pericarditis, pleuritis, and leukocytosis [4](#page=4) [5](#page=5) [6](#page=6).
* Treatment is typically with aspirin; ibuprofen can be used as a second-line option [4](#page=4) [5](#page=5) [6](#page=6).
### 3.6 Long-term secondary prevention
Lifelong management includes aspirin, a beta-blocker, an ACE inhibitor, and a high-intensity statin, potentially with a P2Y12 inhibitor. Aggressive control of blood pressure, lipids, and diabetes is crucial. Smoking cessation, weight management, and regular exercise are also vital components. Regular follow-up and participation in cardiac rehabilitation are recommended [4](#page=4) [5](#page=5) [6](#page=6).
---
# Differential diagnosis and approach to chest pain
Chest pain is a common and often alarming symptom that requires a systematic approach to identify its cause and exclude life-threatening conditions [7](#page=7) [8](#page=8).
### 4.1 Differential diagnosis of chest pain
A broad differential diagnosis encompasses various organ systems, including cardiac, pulmonary, gastrointestinal, chest wall, psychiatric, and drug-induced causes [7](#page=7) [8](#page=8).
#### 4.1.1 Cardiac, pericardial, and vascular causes
* **Stable angina:** Characterized by exertional, predictable chest pain relieved by rest or nitroglycerin (GTN) [7](#page=7) [8](#page=8).
* **Acute Coronary Syndrome (ACS) - Unstable Angina (UA), NSTEMI, STEMI:** Presents as new or worsening chest pain, potentially occurring at rest, and not fully relieved by GTN. It is caused by plaque rupture and thrombus formation [7](#page=7) [8](#page=8).
* **Variant (Prinzmetal) angina:** Occurs at rest or during the nighttime, caused by coronary vasospasm, and may present with transient ST elevation on ECG [7](#page=7) [8](#page=8).
* **Pericarditis:** Typically causes sharp, pleuritic, and positional chest pain, which worsens when lying flat and improves when sitting forward. A pericardial rub may be present, along with diffuse ST elevation and PR depression on ECG [7](#page=7) [8](#page=8).
* **Aortic dissection:** Characterized by sudden, tearing chest or back pain, with potential differences in pulse or blood pressure between limbs. A history of Marfan syndrome or severe hypertension is a risk factor [7](#page=7) [8](#page=8).
#### 4.1.2 Pulmonary causes
* **Pulmonary embolism (PE):** Presents with pleuritic chest pain, dyspnea, and tachycardia. Risk factors include deep vein thrombosis (DVT), immobility, oral contraceptive pills (OCP), and post-operative states [7](#page=7) [8](#page=8).
* **Pneumothorax (including tension pneumothorax):** Causes sudden pleuritic chest pain, with reduced breath sounds and hyperresonance on the affected side [7](#page=7) [8](#page=8).
* **Pneumonia:** Associated with fever, cough, sputum production, localized pleuritic pain, and crackles on auscultation [7](#page=7) [8](#page=8).
* Other pulmonary causes include pleuritis and severe asthma [7](#page=7) [8](#page=8).
#### 4.1.3 Gastrointestinal causes
* **Gastroesophageal Reflux Disease (GERD):** Manifests as burning retrosternal pain, often worse after meals or lying flat, and may be associated with a sour or bitter taste [7](#page=7) [8](#page=8).
* **Diffuse esophageal spasm:** Causes crushing chest pain and dysphagia, which can mimic ACS [7](#page=7) [8](#page=8).
* **Peptic Ulcer Disease (PUD) / Gastritis:** Primarily presents as epigastric burning [7](#page=7) [8](#page=8).
* **Esophageal rupture (Boerhaave syndrome):** A severe condition following forceful vomiting, causing severe pain and potentially subcutaneous emphysema [7](#page=7) [8](#page=8).
#### 4.1.4 Chest wall, musculoskeletal, and dermatological causes
* **Costochondritis, muscle strain:** Localized pain that is reproducible with palpation or movement [7](#page=7) [8](#page=8).
* **Rib fracture:** Associated with trauma and sharp, pleuritic chest pain [7](#page=7) [8](#page=8).
* **Herpes zoster:** Presents as dermatomal burning pain followed by vesicular rash [7](#page=7) [8](#page=8).
#### 4.1.5 Psychiatric causes
* **Panic attacks, anxiety, somatization:** Can cause chest tightness accompanied by hyperventilation and a "sense of doom" [7](#page=7) [8](#page=8).
#### 4.1.6 Drug-induced causes
* **Cocaine / Methamphetamine:** Can induce coronary vasospasm and thrombosis, mimicking an MI, particularly in younger patients [7](#page=7) [8](#page=8).
### 4.2 High-yield clues for chest pain
Several clues can help narrow the differential diagnosis [7](#page=7) [8](#page=8):
* Pain relieved by GTN suggests a cardiac etiology is more likely [7](#page=7) [8](#page=8).
* Pleuritic, positional pain, or pain reproducible by palpation makes ischemic heart disease less likely [7](#page=7) [8](#page=8).
* **Crucially, always exclude life-threatening conditions:**
* Acute Coronary Syndrome (ACS) [7](#page=7) [8](#page=8).
* Aortic dissection [7](#page=7) [8](#page=8).
* Pulmonary embolism (PE) [7](#page=7) [8](#page=8).
* Cardiac tamponade [7](#page=7) [8](#page=8).
* Tension pneumothorax [7](#page=7) [8](#page=8).
* Esophageal rupture [7](#page=7) [8](#page=8).
> **Tip:** The mnemonic "5 Hs and 5 Ts" (Hypoxia, Hypovolemia, Hydrogen ion, Hypo/hyperkalemia, Hypothermia; Tension pneumothorax, Tamponade, Toxins, Thrombosis - pulmonary or coronary) can be helpful for remembering reversible causes of cardiac arrest, some of which present with chest pain [7](#page=7) [8](#page=8).
### 4.3 Approach to a patient with chest pain
A structured approach is essential for the timely and accurate diagnosis of chest pain [7](#page=7) [8](#page=8).
#### 4.3.1 Immediate assessment
* Prioritize ABCs (Airway, Breathing, Circulation) and initiate resuscitation if the patient is unstable [7](#page=7) [8](#page=8).
* Obtain vital signs: Heart Rate (HR), Blood Pressure (BP) (ideally in both arms), Respiratory Rate (RR), Oxygen Saturation (SpO₂), and Temperature [7](#page=7) [8](#page=8).
#### 4.3.2 Focused history
Gather detailed information about the pain and associated symptoms:
* **Character:** Describe the pain (e.g., pressure, squeezing, sharp, tearing) [7](#page=7) [8](#page=8).
* **Location and radiation:** Where is the pain, and does it radiate (e.g., to the jaw, arm, back)? [7](#page=7) [8](#page=8).
* **Severity:** Use a 0-10 pain scale [7](#page=7) [8](#page=8).
* **Duration:** How long has the pain lasted (seconds, minutes, hours)? [7](#page=7) [8](#page=8).
* **Setting:** When did the pain occur (exertion, rest, after meals, following trauma)? [7](#page=7) [8](#page=8).
* **Aggravating/relieving factors:** What makes the pain worse or better (e.g., exertion, breathing, position, food, GTN)? [7](#page=7) [8](#page=8).
* **Associated symptoms:** Note any accompanying symptoms such as dyspnea, diaphoresis (sweating), syncope (fainting), cough, fever, or gastrointestinal complaints [7](#page=7) [8](#page=8).
* **Risk factors and history:** Inquire about history of coronary artery disease (CAD), hypertension (HTN), diabetes mellitus (DM), smoking, family history (FHx) of heart disease, recent surgery, OCP use, history of DVT, and intravenous drug use (IVDU) [7](#page=7) [8](#page=8).
#### 4.3.3 Focused physical examination
* **General appearance:** Assess for distress, diaphoresis, and cyanosis [7](#page=7) [8](#page=8).
* **Cardiac:** Examine Jugular Venous Pressure (JVP), listen for murmurs, rubs, gallops, and note any displaced apex beat [7](#page=7) [8](#page=8).
* **Respiratory:** Assess air entry, listen for crackles, wheezes, hyperresonance, or dullness [7](#page=7) [8](#page=8).
* **Vascular:** Check pulses, look for BP asymmetry between arms, peripheral edema, and signs of DVT [7](#page=7) [8](#page=8).
* **Chest wall/abdomen/skin:** Palpate for tenderness, check for epigastric pain, and examine for any zoster rash [7](#page=7) [8](#page=8).
#### 4.3.4 Core investigations
* **ECG:** Should be performed in all but the most trivial cases of chest pain. Repeat ECGs if suspicion remains high [7](#page=7) [8](#page=8).
* **Cardiac enzymes:** Measure CK, CK-MB, and troponin levels [7](#page=7) [8](#page=8).
* **Chest X-ray (CXR):** Useful for identifying pneumonia, pneumothorax (PTX), heart failure (HF), or a widened mediastinum [7](#page=7) [8](#page=8).
* **Further investigations:** Consider D-dimer/CT Pulmonary Angiography (CTPA) for suspected PE, echocardiogram, or other tests based on clinical suspicion [7](#page=7) [8](#page=8).
#### 4.3.5 Risk stratification and working diagnosis
* **Low-risk patients:** A young patient with a low-risk profile and a clear GERD history may be treated for GERD and reviewed [7](#page=7) [8](#page=8).
* **High-risk patients:** Older patients, those with diabetes, or known CAD presenting with typical pain should be treated as having ischemic heart disease until proven otherwise [7](#page=7) [8](#page=8).
#### 4.3.6 Management principle
> **Tip:** "When in doubt in a high-risk patient – over-call ACS, not anxiety.". This emphasizes the importance of prioritizing the exclusion of life-threatening cardiac events [7](#page=7) [8](#page=8).
### 4.4 Special scenario: Known stable angina now worse
Patients with a history of stable angina presenting with worsening symptoms require urgent evaluation [7](#page=7) [8](#page=8).
#### 4.4.1 Features of worsening angina
* New onset of chest pain [7](#page=7) [8](#page=8).
* Increased severity or longer duration of pain [7](#page=7) [8](#page=8).
* Pain occurring at rest [7](#page=7) [8](#page=8).
#### 4.4.2 Initial steps
* Perform an immediate ECG and obtain cardiac enzyme levels [7](#page=7) [8](#page=8).
* Administer aspirin if there are no contraindications [7](#page=7) [8](#page=8).
* Initiate intravenous heparin if deemed appropriate [7](#page=7) [8](#page=8).
* Admit the patient for further workup and monitoring for ACS [7](#page=7) [8](#page=8).
---
# Congestive heart failure (CHF)
Congestive heart failure (CHF) is a complex clinical syndrome characterized by the heart's inability to adequately meet the body's circulatory demands under normal physiological conditions [10](#page=10) [9](#page=9).
### 5.1 General characteristics of CHF
#### 5.1.1 Definition and final common pathway
CHF is a clinical syndrome where the heart cannot meet the body's circulatory demands under normal physiologic conditions. It represents the final common pathway for many different cardiac diseases [10](#page=10) [9](#page=9).
#### 5.1.2 Types by ejection fraction
CHF is primarily categorized based on the left ventricular ejection fraction (LVEF):
* **HFrEF (heart failure with reduced ejection fraction)**, also known as systolic heart failure, is defined by an LVEF < 40% and is characterized by impaired contractility [10](#page=10) [9](#page=9).
* **HFpEF (heart failure with preserved ejection fraction)**, also known as diastolic heart failure, is defined by an LVEF ≥ 50% and is characterized by impaired relaxation or a stiff left ventricle [10](#page=10) [9](#page=9).
#### 5.1.3 High-output heart failure
High-output heart failure occurs when cardiac output is increased, but it is still inadequate to meet the body's tissue oxygen demand. Causes include chronic anemia, pregnancy, hyperthyroidism, arteriovenous (AV) fistulas, wet beriberi, mitral regurgitation (MR), and aortic insufficiency [10](#page=10) [9](#page=9).
#### 5.1.4 Core pathophysiology
The core pathophysiology involves a decrease in cardiac output ($CO$). This triggers neurohormonal activation, primarily the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS). These systems lead to sodium and water retention, vasoconstriction, and cardiac remodeling, ultimately exacerbating the symptoms of heart failure [10](#page=10) [9](#page=9).
### 5.2 Pathophysiology details
#### 5.2.1 Frank–Starling relationship
The Frank–Starling mechanism describes the relationship between ventricular preload and stroke volume. In a normal heart, increased preload leads to increased stroke volume. However, in a failing heart, this relationship is altered; the curve flattens, meaning that further increases in preload provide little benefit and can actually be detrimental [10](#page=10) [9](#page=9).
#### 5.2.2 Main etiologies of HFrEF
The primary causes of HFrEF include:
* Ischemic heart disease and prior myocardial infarction (MI) [10](#page=10) [9](#page=9).
* Long-standing hypertension [10](#page=10) [9](#page=9).
* Dilated, toxic, or postpartum cardiomyopathy [10](#page=10) [9](#page=9).
* Valvular disease, such as MR, aortic regurgitation (AR), and aortic stenosis (AS) [10](#page=10) [9](#page=9).
* Myocarditis, including viral and autoimmune causes [10](#page=10) [9](#page=9).
* Infiltrative diseases like amyloidosis, sarcoidosis, hemochromatosis, and Wilson disease [10](#page=10) [9](#page=9).
* Drug-induced cardiotoxicity (e.g., alcohol, cocaine, methamphetamine, anthracyclines, trastuzumab) [10](#page=10) [9](#page=9).
* Thyroid disease, peripartum cardiomyopathy, and congenital or hereditary causes [10](#page=10) [9](#page=9).
#### 5.2.3 HFpEF (diastolic HF)
HFpEF is characterized by impaired left ventricular (LV) filling during diastole, leading to elevated filling pressures despite a normal LVEF on echocardiogram. Common causes include long-standing hypertension with LV hypertrophy (LVH), AS, hypertrophic cardiomyopathy (HCM), and restrictive cardiomyopathy [10](#page=10) [9](#page=9).
#### 5.2.4 Neurohormonal compensation and maladaptation
When cardiac output ($CO$) decreases, the body activates compensatory mechanisms.
* **SNS activation** increases heart rate ($HR$), contractility, and vasoconstriction [10](#page=10) [9](#page=9).
* **RAAS activation** and Antidiuretic Hormone (ADH) release lead to sodium and water retention, increasing preload [10](#page=10) [9](#page=9).
While these mechanisms are initially beneficial, their chronic activation leads to detrimental effects like fibrosis and cardiac remodeling, ultimately worsening heart failure [10](#page=10) [9](#page=9).
### 5.3 Clinical features
#### 5.3.1 Left-sided heart failure – symptoms
Symptoms of left-sided heart failure are primarily related to pulmonary congestion and reduced systemic perfusion:
* Dyspnea (shortness of breath), initially on exertion, progressing to dyspnea at rest [10](#page=10) [9](#page=9).
* Orthopnea (difficulty breathing when lying flat, requiring pillows for support) [10](#page=10) [9](#page=9).
* Paroxysmal nocturnal dyspnea (PND) - sudden awakening with severe dyspnea [10](#page=10) [9](#page=9).
* Nocturnal cough, often worse when lying flat [10](#page=10) [9](#page=9).
* Fatigue and weakness due to decreased systemic perfusion [10](#page=10) [9](#page=9).
* Confusion and memory issues in advanced stages due to reduced brain perfusion [10](#page=10) [9](#page=9).
#### 5.3.2 Left-sided heart failure – signs
Physical examination findings in left-sided heart failure include:
* Displaced apex beat, indicating cardiomegaly [10](#page=10) [9](#page=9).
* S3 gallop, a sound heard during rapid ventricular filling into a dilated LV [10](#page=10) [9](#page=9).
* S4 gallop, an abnormal sound caused by atrial contraction into a stiff LV [10](#page=10) [9](#page=9).
* Crackles or rales at the lung bases, indicative of pulmonary edema [10](#page=10) [9](#page=9).
* Dullness and decreased fremitus at the lung bases, suggestive of pleural effusion [10](#page=10) [9](#page=9).
* Loud P2, which can indicate pulmonary hypertension [10](#page=10) [9](#page=9).
#### 5.3.3 NYHA functional classes
The New York Heart Association (NYHA) functional classification stratifies heart failure severity:
* **Class I:** Symptoms only with vigorous physical activity.
* **Class II:** Symptoms with moderate exertion (e.g., climbing stairs, walking uphill).
* **Class III:** Symptoms with minimal exertion (e.g., activities of daily living, walking in the room).
* **Class IV:** Symptoms at rest, often incapacitating. [10](#page=10) [9](#page=9).
#### 5.3.4 Right-sided heart failure – symptoms and signs
Right-sided heart failure symptoms and signs are primarily related to systemic venous congestion:
* Peripheral pitting edema, commonly in the ankles and sacrum [10](#page=10) [9](#page=9).
* Nocturia (frequent urination at night) [10](#page=10) [9](#page=9).
* Jugular venous distension (JVD) [10](#page=10) [9](#page=9).
* Hepatomegaly (enlarged liver) and hepatojugular reflux [10](#page=10) [9](#page=9).
* Ascites (fluid accumulation in the peritoneal cavity) [10](#page=10) [9](#page=9).
* RV heave, a palpable impulse at the lower left sternal border, often indicative of RV hypertrophy, frequently due to pulmonary hypertension [10](#page=10) [9](#page=9).
#### 5.3.5 Interaction between left and right heart failure
Long-standing left-sided heart failure can lead to pulmonary hypertension, which in turn can cause secondary right-sided heart failure. Therefore, many patients present with features of both left and right heart failure [10](#page=10) [9](#page=9).
### 5.4 Diagnosis
#### 5.4.1 Chest X-ray (CXR)
A chest X-ray can reveal:
* Cardiomegaly [10](#page=10) [9](#page=9).
* Pulmonary venous congestion [10](#page=10) [9](#page=9).
* Kerley B lines, indicative of interstitial edema [10](#page=10) [9](#page=9).
* Pleural effusions or alveolar edema [10](#page=10) [9](#page=9).
#### 5.4.2 Echocardiogram
The echocardiogram is a key diagnostic tool for CHF, as it:
* Differentiates between systolic (HFrEF) and diastolic (HFpEF) dysfunction [10](#page=10) [9](#page=9).
* Estimates LVEF (<40% for HFrEF; ≥50% for HFpEF) [10](#page=10) [9](#page=9).
* Assesses chamber size, wall thickness, hypertrophy, and valvular or pericardial disease [10](#page=10) [9](#page=9).
#### 5.4.3 BNP / NT-proBNP
B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are biomarkers released in response to increased ventricular volume and pressure.
* A BNP level >100 pg/mL suggests decompensated heart failure [10](#page=10) [9](#page=9).
* An NT-proBNP level <300 pg/mL can help rule out heart failure, although this value is age-adjusted and may be lower in obese individuals [10](#page=10) [9](#page=9).
#### 5.4.4 ECG
An electrocardiogram (ECG) is usually nonspecific but may reveal:
* Evidence of prior MI or ischemia [10](#page=10) [9](#page=9).
* Left ventricular hypertrophy (LVH) [10](#page=10) [9](#page=9).
* Arrhythmias [10](#page=10) [9](#page=9).
#### 5.4.5 Additional tests
Other diagnostic tests may include:
* **Labs:** Complete blood count (CBC), basic metabolic panel (BMP) or urea and electrolytes (U&Es), cardiac enzymes, liver function tests (LFTs), and thyroid function tests [10](#page=10) [9](#page=9).
* **Radionuclide ventriculography (MUGA scan):** For precise EF measurement [10](#page=10) [9](#page=9).
* **Cardiac catheterization:** To clarify the etiology of heart failure and assess for coronary artery disease (CAD) [10](#page=10) [9](#page=9).
* **Stress testing:** To evaluate for ischemia and assess functional capacity [10](#page=10) [9](#page=9).
### 5.5 Treatment
#### 5.5.1 HFrEF (Systolic HF)
Treatment strategies for HFrEF aim to relieve symptoms, reduce mortality, and prevent hospitalizations.
**Lifestyle Modifications:**
* Sodium restriction to less than 4 grams per day [10](#page=10) [9](#page=9).
* Fluid restriction to 1.5–2 liters per day if symptomatic [10](#page=10) [9](#page=9).
* Weight loss, smoking cessation, and alcohol reduction [10](#page=10) [9](#page=9).
* Regular exercise programs and daily weight monitoring [10](#page=10) [9](#page=9).
* Annual influenza and pneumococcal vaccinations [10](#page=10) [9](#page=9).
**Diuretics:**
* Used for symptom relief in cases of volume overload [10](#page=10) [9](#page=9).
* **Loop diuretics:** Furosemide, bumetanide, torsemide [10](#page=10) [9](#page=9).
* **Thiazide-like diuretics:** Metolazone, chlorthiazide, used for resistant edema [10](#page=10) [9](#page=9).
**Mortality-Reducing Drugs:** These are the cornerstone of HFrEF therapy.
* **ACE inhibitors (ACEI) or Angiotensin Receptor Blockers (ARB):** Or Angiotensin Receptor-Neprilysin Inhibitors (ARNI) like sacubitril/valsartan [10](#page=10) [9](#page=9).
* **Beta-blockers:** Specific agents like metoprolol succinate, carvedilol, and bisoprolol [10](#page=10) [9](#page=9).
* **Aldosterone antagonists:** Spironolactone or eplerenone, particularly for patients with an LVEF < 35% [10](#page=10) [9](#page=9).
* **Hydralazine and nitrates:** Often used in Black/African patients [10](#page=10) [9](#page=9).
* **Implantable Cardioverter-Defibrillator (ICD):** Indicated for LVEF ≤ 35% on optimal medical therapy to prevent sudden cardiac death from ventricular arrhythmias [10](#page=10) [9](#page=9).
**Other Medications:**
* **Ivabradine:** May be considered for patients with a heart rate > 70 beats per minute on maximal beta-blocker therapy with a reduced EF [10](#page=10) [9](#page=9).
* **Digoxin:** Can be used for symptom relief and to reduce hospitalizations but does not improve mortality [10](#page=10) [9](#page=9).
> **Tip:** The biggest killer in heart failure is sudden ventricular arrhythmia, underscoring the importance of ICDs in appropriate patients [10](#page=10) [9](#page=9).
#### 5.5.2 HFpEF (Diastolic HF)
* Currently, no medication has been proven to reduce mortality in HFpEF [10](#page=10) [9](#page=9).
* Management focuses on treating underlying conditions such as hypertension, ischemia, atrial fibrillation (AF), and other comorbidities [10](#page=10) [9](#page=9).
* Diuretics are used to manage congestion [10](#page=10) [9](#page=9).
* Salt and fluid restriction, daily weight monitoring, and lifestyle modifications are also recommended [10](#page=10) [9](#page=9).
#### 5.5.3 General principles of CHF treatment
Regardless of EF type, general management principles apply:
* Treat the underlying cause of heart failure (e.g., hypertension, CAD, valvular disease) [10](#page=10) [9](#page=9).
* Avoid NSAIDs, as they can lead to fluid retention and kidney injury [10](#page=10) [9](#page=9).
* Emphasize patient education regarding diet, medication adherence, and recognizing warning signs to seek medical help [10](#page=10) [9](#page=9).
* Consider cardiac rehabilitation to improve symptoms and overall survival [10](#page=10) [9](#page=9).
---
# Cardiomyopathies and myocarditis
Cardiomyopathies and myocarditis encompass a group of diseases affecting the heart muscle, leading to impaired function and potential heart failure or sudden death.
## 6. Cardiomyopathies and myocarditis
### 6.1 Hypertrophic cardiomyopathy (HCM)
#### 6.1.1 General characteristics
Hypertrophic cardiomyopathy (HCM) is a primary cardiomyopathy characterized by left ventricular (LV) hypertrophy, often asymmetric septal thickening. This hypertrophy results in a stiff, noncompliant ventricle that can lead to dynamic LV outflow obstruction. The condition is predominantly inherited in an autosomal dominant pattern, with a family history of sudden cardiac death at a young age being a significant indicator. The primary issue in HCM is diastolic dysfunction, meaning impaired ventricular filling, rather than a primary problem with pumping ability. Sporadic mutations are also possible [11](#page=11) [12](#page=12).
#### 6.1.2 Pathophysiology
The pathophysiology of HCM involves two main mechanisms: diastolic dysfunction and dynamic LV outflow obstruction [11](#page=11) [12](#page=12).
* **Diastolic dysfunction:** The hypertrophied LV wall exhibits impaired relaxation, leading to increased LV diastolic filling pressures. This elevates left atrial (LA) pressure and can result in pulmonary congestion [11](#page=11) [12](#page=12).
* **Dynamic LV outflow obstruction:** This occurs due to asymmetric septal hypertrophy combined with the systolic anterior motion of the mitral valve (SAM-MV). This creates a narrowed LV outflow tract, and the degree of obstruction is influenced by preload, afterload, and contractility [11](#page=11) [12](#page=12).
* **Factors that increase obstruction:** Increased heart rate, increased contractility (e.g., with exercise, stress, or catecholamines), decreased preload (e.g., with Valsalva maneuver, standing, or dehydration), or decreased LV size [11](#page=11) [12](#page=12).
* **Consequences of obstruction:** Reduced cardiac output during exertion, leading to syncope or presyncope, myocardial ischemia due to the thick muscle's high oxygen demand, and an increased risk of ventricular arrhythmias and sudden cardiac death. A Valsalva maneuver decreases venous return to the heart, leading to a reduced volume of blood in the LV (lower preload), which can worsen LVOT obstruction in HCM, making murmurs louder [11](#page=11) [12](#page=12).
#### 6.1.3 Clinical features
Patients with HCM may present with a range of symptoms and signs:
* **Symptoms:**
* Dyspnea on exertion (DOE) [11](#page=11) [12](#page=12).
* Angina-like chest pain [11](#page=11) [12](#page=12).
* Syncope or dizziness, particularly with exertion or Valsalva maneuver [11](#page=11) [12](#page=12).
* Palpitations due to atrial fibrillation (AFib) or ventricular arrhythmias [11](#page=11) [12](#page=12).
* Symptoms of heart failure resulting from diastolic stiffness [11](#page=11) [12](#page=12).
* Sudden cardiac death in young athletes, which can be the first presentation [11](#page=11) [12](#page=12).
* Some patients may remain asymptomatic for many years [11](#page=11) [12](#page=12).
* **Signs:**
* Sustained, forceful point of maximal impulse (PMI) indicating cardiomegaly or LV hypertrophy [11](#page=11) [12](#page=12).
* S₄ gallop, indicative of an atrial kick into a stiff LV [11](#page=11) [12](#page=12).
* Systolic ejection murmur, best heard at the left lower sternal border (LLSB), caused by dynamic LVOT obstruction. This murmur increases with maneuvers that decrease preload (Valsalva, standing) and decreases with maneuvers that increase preload (squatting, lying down) [11](#page=11) [12](#page=12).
* A rapidly rising carotid pulse with two peaks (bisferious pulse) [11](#page=11) [12](#page=12).
#### 6.1.4 Diagnosis
The diagnostic approach for HCM includes:
* **Echocardiogram:** This is the test of choice, revealing asymmetric septal hypertrophy, a small LV cavity with hyperdynamic contraction, and evidence of an LVOT gradient, potentially with SAM-MV [11](#page=11) [12](#page=12).
* **Clinical presentation and family history:** A young patient with exertional syncope or chest pain and a family history of sudden death is highly suggestive of HCM [11](#page=11) [12](#page=12).
* **Additional investigations:**
* Electrocardiogram (ECG): May show LVH, repolarization changes, and arrhythmias [11](#page=11) [12](#page=12).
* Genetic testing and family screening are valuable when available [11](#page=11) [12](#page=12).
#### 6.1.5 Treatment
Management of HCM focuses on symptom relief, preventing complications, and lifestyle modifications:
* **Lifestyle and general measures:**
* Avoidance of strenuous and competitive sports [11](#page=11) [12](#page=12).
* Prevention of dehydration and avoidance of medications that significantly reduce preload or afterload [11](#page=11) [12](#page=12).
* Screening of first-degree relatives [11](#page=11) [12](#page=12).
* **Medical therapy (symptomatic):**
* **Beta-blockers:** First-line treatment to reduce heart rate, improve diastolic filling, and decrease contractility, thereby reducing obstruction and symptoms [11](#page=11) [12](#page=12).
* **Non-dihydropyridine calcium channel blockers (CCBs)** (e.g., verapamil): Used if beta-blockers are not tolerated [11](#page=11) [12](#page=12).
* **Disopyramide:** An add-on negative inotrope used for persistent obstruction [11](#page=11) [12](#page=12).
* **Diuretics:** Used with caution for congestion, avoiding excessive preload reduction [11](#page=11) [12](#page=12).
* Treatment of AFib with rate and rhythm control and anticoagulation as appropriate [11](#page=11) [12](#page=12).
* **Invasive options (for severe, refractory HCM):**
* Alcohol septal ablation (catheter-based septal reduction) [11](#page=11) [12](#page=12).
* Surgical septal myomectomy (resection of hypertrophied septum) [11](#page=11) [12](#page=12).
* Mitral valve repair may be performed concurrently with myomectomy [11](#page=11) [12](#page=12).
* **Sudden death prevention:**
* Consideration of an implantable cardioverter-defibrillator (ICD) in high-risk patients (e.g., prior ventricular tachycardia/fibrillation, family history of sudden cardiac death, massive LVH, syncope) [11](#page=11) [12](#page=12).
### 6.2 Restrictive cardiomyopathy (RCM)
#### 6.2.1 Essence
Restrictive cardiomyopathy (RCM) is defined as an infiltrative or fibrotic disease of the heart muscle that leads to stiff, noncompliant ventricles. This impairs diastolic filling, increasing ventricular compliance. The primary hemodynamic problem is diastolic dysfunction, while systolic function is often preserved early but may decline in advanced stages. The increased filling pressures result in pulmonary and systemic congestion. RCM is less common than dilated or hypertrophic cardiomyopathy. Clinically, it can mimic constrictive pericarditis due to similar presentations of increased right-sided heart filling pressures [13](#page=13) [14](#page=14).
#### 6.2.2 Causes
The causes of RCM can be remembered using the mnemonic ASH-SCI:
* **A**myloidosis [13](#page=13) [14](#page=14).
* **S**arcoidosis [13](#page=13) [14](#page=14).
* **H**emochromatosis [13](#page=13) [14](#page=14).
* **S**cleroderma [13](#page=13) [14](#page=14).
* **C**arcinoid syndrome [13](#page=13) [14](#page=14).
* **C**hemo/radiation-induced [13](#page=13) [14](#page=14).
* **I**diopathic [13](#page=13) [14](#page=14).
#### 6.2.3 Clinical features
Symptoms in RCM are primarily due to increased filling pressures:
* Dyspnea and exercise intolerance [13](#page=13) [14](#page=14).
* Fatigue and weakness [13](#page=13) [14](#page=14).
* Right-sided heart failure signs are often prominent, including peripheral edema, hepatomegaly with ascites, and jugular venous distension (JVD) [13](#page=13) [14](#page=14).
#### 6.2.4 Diagnosis
Diagnostic tools for RCM include:
* **Echocardiogram (key test):** Reveals thickened, stiff myocardium, bi-atrial enlargement, and normal to near-normal systolic function early on, which declines in advanced disease. Amyloidosis may show a "bright/speckled" myocardium [13](#page=13) [14](#page=14).
* **ECG:** May show low voltages (especially in amyloidosis), conduction abnormalities, AFib, and other arrhythmias [13](#page=13) [14](#page=14).
* **Endomyocardial biopsy:** Can confirm infiltrative diseases like amyloidosis or sarcoidosis [13](#page=13) [14](#page=14).
#### 6.2.5 Treatment
Management of RCM involves treating the underlying cause and supportive care:
* **Treat underlying disorder:** Phlebotomy or deferoxamine for hemochromatosis, glucocorticoids for sarcoidosis flares, and disease-specific therapy for amyloidosis. Transplant may be considered in severe amyloidosis [13](#page=13) [14](#page=14).
* **Heart failure (HF) therapy:** Based on ejection fraction (EF). Standard HFrEF medications are used if an HFrEF pattern is present. For HFpEF patterns, therapy is symptomatic as no mortality-proven drugs exist [13](#page=13) [14](#page=14).
* **Diuretics and vasodilators:** Used for edema, but cautiously, as excessive preload reduction can decrease cardiac output [13](#page=13) [14](#page=14).
* **Rhythm management:** Treating AFib and other arrhythmias according to guidelines [13](#page=13) [14](#page=14).
### 6.3 Myocarditis
#### 6.3.1 Essence
Myocarditis is defined as inflammation of the myocardium, leading to myocyte injury and necrosis. The typical patient is a young male with a recent viral illness who presents with chest pain, shortness of breath, or palpitations. Outcomes can range from full recovery to progression to dilated cardiomyopathy, arrhythmias, or sudden death [13](#page=13) [14](#page=14).
#### 6.3.2 Causes
The causes of myocarditis can be categorized as:
* **Infectious:** Viral (most common, e.g., Coxsackie, parvovirus B19, HHV-6), bacterial (e.g., group A strep, Lyme, mycoplasma), and others like protozoa [13](#page=13) [14](#page=14).
* **Autoimmune/systemic:** Systemic lupus erythematosus (SLE), rheumatic fever, and other connective-tissue diseases [13](#page=13) [14](#page=14).
* **Drugs/toxins:** Certain medications like sulfonamides [13](#page=13) [14](#page=14).
* **Idiopathic** [13](#page=13) [14](#page=14).
#### 6.3.3 Clinical features
Patients with myocarditis may be asymptomatic or present with:
* **Viral-like prodrome:** Fever, malaise, myalgias [13](#page=13) [14](#page=14).
* **Cardiac symptoms:**
* Chest pain, which can mimic myocardial infarction [13](#page=13) [14](#page=14).
* Dyspnea, orthopnea, and signs of congestive heart failure (CHF) [13](#page=13) [14](#page=14).
* Palpitations, arrhythmias, and syncope [13](#page=13) [14](#page=14).
* Signs of coexisting pericarditis (pleuritic chest pain) [13](#page=13) [14](#page=14).
* **Severe cases:** Cardiogenic shock or sudden cardiac death [13](#page=13) [14](#page=14).
#### 6.3.4 Investigations
Diagnostic investigations for myocarditis include:
* **Labs:** Elevated cardiac enzymes (troponin, CK) and inflammatory markers (ESR, CRP) [13](#page=13) [14](#page=14).
* **ECG:** Non-specific ST-T changes, arrhythmias, and conduction blocks [13](#page=13) [14](#page=14).
* **Echocardiogram:** May show global or regional LV dysfunction, dilated chambers, and reduced EF [13](#page=13) [14](#page=14).
* **Biopsy (in select cases):** Confirms inflammatory infiltrate and myocyte necrosis [13](#page=13) [14](#page=14).
#### 6.3.5 Management
Management of myocarditis is primarily supportive and aims to treat the underlying cause:
* **Supportive HF care:** Diuretics for congestion, ACE inhibitors/ARBs and beta-blockers if LV dysfunction is present (as tolerated), and oxygen/ventilatory support if severe [13](#page=13) [14](#page=14).
* **Treat underlying cause:** Appropriate antimicrobials for bacterial infections, and immunosuppression in selected autoimmune forms [13](#page=13) [14](#page=14).
* **Arrhythmia management:** Antiarrhythmics, temporary pacing, or defibrillators as needed [13](#page=13) [14](#page=14).
* **Follow-up:** Monitoring of LV function and observation for progression to dilated cardiomyopathy [13](#page=13) [14](#page=14).
---
# Pericardial diseases
This section outlines acute pericarditis, constrictive pericarditis, and pericardial effusion, detailing their definitions, causes, clinical presentations, diagnostic approaches, and management strategies [15](#page=15) [16](#page=16) [17](#page=17) [18](#page=18).
### 7.1 Acute pericarditis
Acute pericarditis is characterized by inflammation of the pericardial sac, which can occur as an isolated event or as part of a systemic illness, and is typically self-limiting, resolving within 2 to 6 weeks [15](#page=15) [16](#page=16).
#### 7.1.1 Causes
The causes of acute pericarditis are diverse and can be categorized as follows [15](#page=15) [16](#page=16):
* **Idiopathic / Post-viral:** This is the most common cause, often occurring after a flu-like illness, upper respiratory tract infection (URTI), or gastrointestinal infection [15](#page=15) [16](#page=16).
* **Infectious:**
* Viral: Including Coxsackie, echovirus, adenovirus, EBV, influenza, HIV, hepatitis A/B [15](#page=15) [16](#page=16).
* Bacterial: Especially tuberculosis [15](#page=15) [16](#page=16).
* Fungal and toxoplasmosis are also possible [15](#page=15) [16](#page=16).
* **Post-Myocardial Infarction (MI):**
* Acute MI pericarditis: Occurs within the first 24 hours post-MI [15](#page=15) [16](#page=16).
* Dressler syndrome: An autoimmune phenomenon occurring weeks to months later [15](#page=15) [16](#page=16).
* **Metabolic / Systemic:**
* Uremia secondary to renal failure [15](#page=15) [16](#page=16).
* Collagen vascular diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), scleroderma, sarcoidosis [15](#page=15) [16](#page=16).
* Amyloidosis [15](#page=15) [16](#page=16).
* **Neoplastic:** Associated with cancers like Hodgkin lymphoma, breast, and lung cancers [15](#page=15) [16](#page=16).
* **Drug-induced Lupus:** Medications such as procainamide and hydralazine can induce lupus-like syndromes [15](#page=15) [16](#page=16).
* **Iatrogenic / Trauma:** Including post-cardiotomy syndrome, radiation exposure, and chest trauma [15](#page=15) [16](#page=16).
A mnemonic for remembering the causes is "I VINDICATE HEART" – Idiopathic, Viral, Infarction, Neoplasm, Drug, Immune, CKD/uremia, Amyloid, Trauma, Exposure (radiation), HEART surgery [15](#page=15) [16](#page=16).
#### 7.1.2 Clinical features
The hallmark symptoms and signs of acute pericarditis include [15](#page=15) [16](#page=16):
* **Chest Pain:** Typically sharp, severe, and pleuritic. It is often positional, worsening when supine and improving when sitting up or leaning forward. Radiation to the trapezius ridge or neck is common [15](#page=15) [16](#page=16).
* **Systemic Signs:** Fever and leukocytosis may be present, often following a recent viral illness characterized by a dry cough, diarrhea, or malaise [15](#page=15) [16](#page=16).
* **Pericardial Friction Rub:** A scratching, high-pitched sound that can have up to three components, corresponding to atrial systole, ventricular systole (loudest), and early diastole. It is best heard when the patient is sitting up, leaning forward, and during expiration [15](#page=15) [16](#page=16).
> **Tip:** The pericardial friction rub is a crucial physical finding, though it may be transient [15](#page=15) [16](#page=16).
#### 7.1.3 Diagnosis
Diagnosis of acute pericarditis relies on meeting at least two of the four diagnostic criteria [15](#page=15) [16](#page=16):
* Typical pleuritic, positional chest pain [15](#page=15) [16](#page=16).
* Pericardial friction rub [15](#page=15) [16](#page=16).
* Electrocardiogram (ECG) findings: diffuse ST segment elevation ($ST^{\wedge}$) and PR segment depression ($PR^{\times}$), with PR depression in lead aVR ($PR^{\wedge}$) [15](#page=15) [16](#page=16).
* Pericardial effusion [15](#page=15) [16](#page=16).
ECG changes typically evolve through four stages [15](#page=15) [16](#page=16):
* **Stage 1:** Diffuse concave ST segment elevation ($ST^{\wedge}$) and PR segment depression ($PR^{\times}$) [15](#page=15) [16](#page=16).
* **Stage 2:** ST segments return to baseline [15](#page=15) [16](#page=16).
* **Stage 3:** T-wave inversion [15](#page=15) [16](#page=16).
* **Stage 4:** T waves normalize [15](#page=15) [16](#page=16).
Echocardiography is essential for detecting pericardial effusion and assessing for cardiac tamponade. Laboratory investigations may include elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and possibly elevated troponin levels. A chest X-ray (CXR) is often normal; however, a large effusion may lead to a "water bottle" shaped cardiac silhouette [15](#page=15) [16](#page=16).
#### 7.1.4 Treatment
The management of acute pericarditis involves [15](#page=15) [16](#page=16):
* **General Measures:** Treating the underlying cause is paramount. Most cases resolve within 2 to 6 weeks [15](#page=15) [16](#page=16).
* **First-line Treatment:** High-dose non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, naproxen, or indomethacin. Colchicine is frequently used as an adjunct to reduce the risk of recurrence [15](#page=15) [16](#page=16).
* **Second-line Treatment:** Glucocorticoids are reserved for cases where NSAIDs and colchicine are ineffective or contraindicated [15](#page=15) [16](#page=16).
* **Disposition:** Patients with mild symptoms and no red flags can be managed as outpatients. Hospitalization is recommended for those with fever, leukocytosis, large pericardial effusion, signs of tamponade, immunosuppression, a history of trauma, or suspicion of a tuberculous or bacterial cause [15](#page=15) [16](#page=16).
#### 7.1.5 Complications
Complications of acute pericarditis can include pericardial effusion, cardiac tamponade (a life-threatening condition), recurrent pericarditis, and chronic constrictive pericarditis, particularly in cases of tuberculosis, surgery, or radiation [15](#page=15) [16](#page=16).
### 7.2 Constrictive pericarditis
Constrictive pericarditis is a chronic condition characterized by fibrous scarring and thickening of the pericardium, leading to a rigid "box" that impairs ventricular compliance. This results in an abrupt halt of ventricular filling in early diastole after initial rapid filling, often described by the "dip-and-plateau" or "square-root sign" on cardiac catheterization [17](#page=17) [18](#page=18).
#### 7.2.1 Causes
Common causes of constrictive pericarditis include [17](#page=17) [18](#page=18):
* Idiopathic or post-viral pericarditis (most common in literature) [17](#page=17) [18](#page=18).
* Recurrent pericarditis [17](#page=17) [18](#page=18).
* Uremia [17](#page=17) [18](#page=18).
* Radiation therapy to the chest [17](#page=17) [18](#page=18).
* Chronic pericardial effusion [17](#page=17) [18](#page=18).
* Tumor invasion [17](#page=17) [18](#page=18).
* Connective tissue disorders [17](#page=17) [18](#page=18).
* Post-pericardial surgery and tuberculosis are considered high-yield local causes [17](#page=17) [18](#page=18).
#### 7.2.2 Pathophysiology
The fibrotic pericardium restricts the total diastolic volume the heart can accommodate. Once the limited diastolic volume is reached, ventricular filling ceases abruptly, leading to systemic venous congestion and a reduced cardiac output (CO) [17](#page=17) [18](#page=18).
#### 7.2.3 Clinical features
Patients typically present with symptoms of fluid overload and low cardiac output [17](#page=17) [18](#page=18):
* **Symptoms of Fluid Overload:** Peripheral edema, ascites, and pleural effusions [17](#page=17) [18](#page=18).
* **Symptoms of Low Output:** Dyspnea on exertion, fatigue, exercise intolerance, and weight loss or cachexia [17](#page=17) [18](#page=18).
* Patients often appear chronically ill [17](#page=17) [18](#page=18).
#### 7.2.4 Key Signs
Significant physical exam findings, often referred to as "exam bait," include [17](#page=17) [18](#page=18):
* Elevated jugular venous pressure (JVP) with prominent x and y descents [17](#page=17) [18](#page=18).
* Kussmaul sign: JVP increases with inspiration [17](#page=17) [18](#page=18).
* Pericardial knock: An early diastolic sound [17](#page=17) [18](#page=18).
* Ascites and dependent edema [17](#page=17) [18](#page=18).
* The presentation can mimic restrictive cardiomyopathy [17](#page=17) [18](#page=18).
#### 7.2.5 Investigations
Diagnostic investigations for constrictive pericarditis include [17](#page=17) [18](#page=18):
* **ECG:** Characteristically shows low QRS voltage and general T-wave flattening or inversion. Atrial fibrillation (AFib) is common in advanced disease [17](#page=17) [18](#page=18).
* **Echocardiogram:** May reveal thickened pericardium in approximately half of patients, an abrupt halt of diastolic filling, and atrial enlargement [17](#page=17) [18](#page=18).
* **CT / MRI:** Useful for visualizing pericardial thickening and calcification [17](#page=17) [18](#page=18).
* **Cardiac Catheterization:** Demonstrates equalized diastolic pressures in all cardiac chambers and the characteristic dip-and-plateau ventricular pressure tracing [17](#page=17) [18](#page=18).
#### 7.2.6 Management
Management strategies for constrictive pericarditis involve [17](#page=17) [18](#page=18):
* Treating the underlying cause, such as tuberculosis or uremia [17](#page=17) [18](#page=18).
* Diuretics may be used cautiously for fluid overload, with careful attention to preload [17](#page=17) [18](#page=18).
* Surgical pericardiectomy is the definitive therapy for severe or refractory cases, carrying significant risk but offering the potential for cure [17](#page=17) [18](#page=18).
### 7.3 Pericardial effusion
A pericardial effusion is the accumulation of excess fluid within the pericardial space. It often arises from acute pericarditis or states of volume retention and can be acute or chronic, with acute effusions posing a higher risk of cardiac tamponade [17](#page=17) [18](#page=18).
#### 7.3.1 Associations and Causes
Pericardial effusions can be associated with any cause of acute pericarditis, as well as conditions leading to salt and water retention such as congestive heart failure (CHF), cirrhosis, nephrotic syndrome, malignancy, tuberculosis, and post-surgical states [17](#page=17) [18](#page=18).
#### 7.3.2 Clinical features
Pericardial effusions are often asymptomatic, with suspicion arising from the underlying disease. Nonspecific physical exam findings may include muffled heart sounds, a soft or poorly localized point of maximal impulse (PMI), dullness at the left lung base, and potentially a pericardial friction rub (though its presence is variable). Signs of tamponade (hypotension, elevated JVP, pulsus paradoxus) should be actively sought if the effusion is large or has developed rapidly [17](#page=17) [18](#page=18).
#### 7.3.3 Investigations
* **Echocardiogram:** This is the test of choice, capable of detecting the presence and size of an effusion, even with as little as approximately 20 mL of fluid [17](#page=17) [18](#page=18).
* **Chest X-ray (CXR):** An enlarged cardiac silhouette, described as a "water bottle" heart, may be seen if the effusion exceeds 250 mL. Clear lungs often suggest an effusion [17](#page=17) [18](#page=18).
* **ECG:** May show low QRS voltage. Electrical alternans, indicative of a massive effusion with a swinging heart, can be observed [17](#page=17) [18](#page=18).
* **CT / MRI:** Highly accurate but usually not required if echocardiography is performed [17](#page=17) [18](#page=18).
* **Pericardial Fluid Analysis (if tapped):** Includes assessment of protein, glucose, cell count and differential, cytology, hematocrit, specific gravity, Gram stain, AFB stain, fungal studies, cultures, LDH, and mycobacterial PCR [17](#page=17) [18](#page=18).
#### 7.3.4 Management
* **Stable, Small to Moderate Effusion:** Management focuses on treating the underlying cause and clinical monitoring, with repeat echocardiography in one to two weeks if necessary [17](#page=17) [18](#page=18).
* **Pericardiocentesis:** Indicated for hemodynamic compromise (cardiac tamponade) or when diagnostic fluid analysis is required to determine the cause [17](#page=17) [18](#page=18).
* **Additional Notes:** Large, chronic effusions may benefit from gradual drainage. It is crucial to continuously reassess for recurrence or progression to tamponade [17](#page=17) [18](#page=18).
---
# Cardiac tamponade
Cardiac tamponade is a life-threatening condition characterized by the accumulation of pericardial fluid that compresses the heart, impairing its ability to fill and pump effectively [19](#page=19).
### 8.1 General characteristics
#### 8.1.1 Definition
Cardiac tamponade occurs when there is an accumulation of pericardial fluid that compresses the heart [19](#page=19).
#### 8.1.2 Rate vs volume
The ability of the pericardium to tolerate fluid accumulation depends on the rate and volume of effusion. A rapid accumulation of as little as 200 milliliters, often seen in trauma, can cause tamponade, while a slower accumulation of up to 2 liters, as can occur with malignancy, may be tolerated without significant symptoms [19](#page=19).
#### 8.1.3 Pathophysiology
The core pathophysiology of cardiac tamponade involves the pericardial effusion mechanically impairing diastolic filling of the heart. This leads to an equalization of diastolic pressures across all cardiac chambers and the pericardium. Consequently, diastolic filling is reduced, leading to a decreased stroke volume (SV) and cardiac output (CO), resulting in hypotension and shock [19](#page=19).
#### 8.1.4 Causes (T-I-P-P-A mnemonic)
The causes of cardiac tamponade can be remembered using the mnemonic T-I-P-P-A [19](#page=19):
* **T**rauma: Especially penetrating trauma, but blunt trauma can also cause it [19](#page=19).
* **I**atrogenic: Complications from medical procedures such as central line insertion, pacemaker placement, or pericardiocentesis [19](#page=19).
* **P**ericarditis with progressive effusion: Inflammation of the pericardium leading to fluid buildup [19](#page=19).
* **P**ost-MI free wall rupture: A rare but critical complication following a myocardial infarction [19](#page=19).
* **A**ortic dissection: Can lead to bleeding into the pericardial space [19](#page=19).
### 8.2 Clinical features
Clinical diagnosis is crucial and should not be delayed by waiting for diagnostic imaging if the patient is unstable [19](#page=19).
#### 8.2.1 Beck triad
Beck triad is a classic presentation of cardiac tamponade and includes [19](#page=19):
* Hypotension [19](#page=19).
* Muffled heart sounds [19](#page=19).
* Elevated jugular venous pressure (JVP), characterized by distended neck veins, absent 'y' descent, and diminished 'x' descent [19](#page=19).
#### 8.2.2 Pulsus paradoxus
Pulsus paradoxus is a significant finding in cardiac tamponade, defined as a decrease in systolic blood pressure of $\geq$ 10 mmHg during inspiration. This results in a pulse that feels strong during expiration and weak during inspiration [19](#page=19).
#### 8.2.3 Other findings
A narrowed pulse pressure can also be observed [19](#page=19).
### 8.3 Diagnosis
#### 8.3.1 Echocardiogram
The echocardiogram is the test of choice for diagnosing cardiac tamponade. It can identify the presence of pericardial effusion, as well as right atrial (RA) and right ventricular (RV) diastolic collapse, and plethora of the inferior vena cava (IVC) [19](#page=19).
#### 8.3.2 Chest X-ray
A chest X-ray may reveal an enlarged cardiac silhouette, often described as a "water bottle" shape, when the effusion exceeds 250 milliliters. Typically, the lung fields will be clear [19](#page=19).
#### 8.3.3 ECG
An electrocardiogram (ECG) may show electrical alternans, which is the beat-to-beat variation in QRS complex amplitude and/or axis, indicative of the heart swinging within the pericardial fluid [19](#page=19).
#### 8.3.4 Cardiac catheterization
Cardiac catheterization can demonstrate equalization of diastolic pressures in all cardiac chambers and a loss of the 'y' descent in the RA pressure tracing [19](#page=19).
### 8.4 Treatment
The treatment of cardiac tamponade depends on whether the effusion is hemorrhagic or non-hemorrhagic and the patient's hemodynamic stability [19](#page=19).
#### 8.4.1 Non-hemorrhagic tamponade
* **Stable patients:** If the patient is hemodynamically stable, close monitoring with serial echocardiograms, chest X-rays, and ECGs is recommended. Treatment should also focus on addressing the underlying cause [19](#page=19).
> **Tip:** In cases of renal failure, dialysis may be a more appropriate intervention than pericardiocentesis for managing fluid overload and effusion [19](#page=19).
* **Unstable patients:** Hemodynamically unstable patients require urgent pericardiocentesis, potentially preceded by a fluid challenge [19](#page=19).
#### 8.4.2 Hemorrhagic tamponade (e.g., trauma)
In cases of hemorrhagic tamponade, such as that caused by trauma, emergent surgery is required to identify and repair the source of bleeding. Pericardiocentesis in this context serves as a temporary measure, and surgical intervention should not be delayed [19](#page=19).
---
# Valvular heart disease: stenosis and regurgitation
This section provides a comprehensive overview of common valvular heart diseases, specifically mitral stenosis, aortic stenosis, aortic regurgitation, and mitral regurgitation, detailing their causes, how they affect heart function, their typical symptoms and physical findings, and how they are diagnosed and managed.
### 9.1 Mitral stenosis (MS)
Mitral stenosis is a condition characterized by a narrowed mitral valve orifice, impeding blood flow from the left atrium (LA) to the left ventricle (LV) [20](#page=20).
#### 9.1.1 Etiology and general principles
* The most common cause of mitral stenosis is rheumatic heart disease, which results from immune-mediated damage to the valve leaflets, leading to scarring and fusion. Anti-strep antibodies can cross-react with valve tissues after untreated streptococcal infections [20](#page=20).
* Symptoms typically arise when the mitral valve area shrinks to less than approximately 1.5 cm² [20](#page=20).
* The mitral valve acts as the door between the LA and LV; in MS, this door becomes stiff and narrow, causing blood to pool in the LA [20](#page=20).
#### 9.1.2 Pathophysiology
* A narrowed mitral valve orifice leads to increased LA pressure [20](#page=20).
* Elevated LA pressure causes increased pulmonary venous pressure [20](#page=20).
* Chronic pulmonary hypertension can result in right ventricular (RV) hypertrophy and eventually RV failure [20](#page=20).
* LA dilation, a consequence of elevated pressure, increases the risk of atrial fibrillation, which can lead to thromboembolism, such as stroke [20](#page=20).
* Atrial fibrillation is an irregular and often fast heart rhythm where the upper chambers of the heart beat chaotically, leading to inefficient blood pumping [20](#page=20).
#### 9.1.3 Clinical features
* **Symptoms:**
* Exertional dyspnea, orthopnea, and paroxysmal nocturnal dyspnea (PND) [20](#page=20).
* Palpitations, often due to atrial fibrillation [20](#page=20).
* Hemoptysis [20](#page=20).
* Signs of RV failure, such as edema and ascites, may be present in advanced disease [20](#page=20).
* **Signs:**
* Loud first heart sound (S1) [20](#page=20).
* An opening snap (OS) heard after the second heart sound (S2) [20](#page=20).
* A low-pitched mid-diastolic rumble heard best at the apex [20](#page=20).
* The severity of MS can be estimated by the timing of the opening snap; a snap closer to S2 indicates more severe stenosis [20](#page=20).
#### 9.1.4 Diagnosis
* **Chest X-ray (CXR):** May show LA enlargement and pulmonary congestion [20](#page=20).
* **Electrocardiogram (ECG):** Can reveal atrial fibrillation and LA enlargement [20](#page=20).
* **Echocardiogram:** Considered the gold standard for diagnosis. It visualizes a thickened, calcified valve, often described as having a "fish-mouth" appearance. Echocardiography quantifies valve area and pressure gradients and assesses pulmonary pressures and RV function [20](#page=20).
#### 9.1.5 Management
* **Medical:**
* Diuretics are used to manage pulmonary congestion [20](#page=20).
* Beta-blockers or other rate-controlling agents are used to slow the heart rate and increase diastolic filling time [20](#page=20).
* Anticoagulation is prescribed if atrial fibrillation is present or if there is a history of emboli [20](#page=20).
* **Interventional:**
* Percutaneous balloon valvuloplasty is the preferred interventional approach if the valve morphology is suitable [20](#page=20).
* Surgical repair or replacement of the mitral valve is indicated for calcified or severe MS [20](#page=20).
* **Follow-up:**
* Mild, asymptomatic MS requires no specific therapy [20](#page=20).
* Careful management is necessary during pregnancy and in high-flow states [20](#page=20).
### 9.2 Aortic stenosis (AS)
Aortic stenosis involves narrowing of the aortic valve, obstructing blood flow from the left ventricle (LV) into the aorta [21](#page=21).
#### 9.2.1 Etiology
* The most common cause in the elderly is calcific degeneration of the aortic valve [21](#page=21).
* In younger adults, a congenital bicuspid aortic valve is a frequent etiology [21](#page=21).
* Rheumatic AS is less common [21](#page=21).
#### 9.2.2 Pathophysiology
* A narrow aortic valve orifice increases the resistance to LV outflow [21](#page=21).
* The LV experiences pressure overload, leading to concentric LV hypertrophy [21](#page=21).
* Over time, the LV may decompensate, resulting in systolic heart failure [21](#page=21).
* A fixed cardiac output can manifest as exertional syncope and angina [21](#page=21).
* The LV cavity may reduce, and the heart can no longer compensate, leading to cardiac arrest [21](#page=21).
#### 9.2.3 Clinical features
* **Symptoms (The "ASH" triad):**
* Angina [21](#page=21).
* Syncope, typically exertional [21](#page=21).
* Heart failure, presenting as dyspnea, orthopnea, and PND [21](#page=21).
* This triad is a poor prognostic sign if untreated [21](#page=21).
* **Signs:**
* A harsh systolic ejection murmur is heard at the right second intercostal space and radiates to the carotids [21](#page=21).
* A soft or absent second heart sound (A2) and an S4 gallop may be present [21](#page=21).
* A "parvus et tardus" carotid pulse, characterized by a pulse that rises slowly and has a decreased amplitude, is indicative of severe AS [21](#page=21).
#### 9.2.4 Diagnosis
* **CXR:** May show LV enlargement and, in late stages, a calcified valve [21](#page=21).
* **ECG:** Typically reveals LV hypertrophy (LVH). LVH can be suggested by a QRS complex summation of S-wave in V1 and R-wave in V5 or V6 exceeding 35 mm [21](#page=21).
* **Echocardiogram:** The gold standard for diagnosis. It shows thickened, restricted valve leaflets and is used to measure valve area and pressure gradients [21](#page=21).
#### 9.2.5 Management
* **Asymptomatic:**
* Monitoring with serial echocardiograms is recommended [21](#page=21).
* An exercise test may be considered if the AS is severe [21](#page=21).
* **Symptomatic or LV dysfunction:**
* Surgical aortic valve replacement (AVR) is the primary treatment [21](#page=21).
* Transcatheter aortic valve replacement (TAVR) is an option for patients at high or intermediate surgical risk [21](#page=21).
* **Medical:**
* Medical management is limited to symptom control and does not alter the prognosis [21](#page=21).
### 9.3 Valvular regurgitation
Valvular regurgitation, also known as insufficiency or incompetence, occurs when a heart valve does not close properly, allowing blood to leak backward [22](#page=22).
#### 9.3.1 Aortic regurgitation (AR)
Aortic regurgitation is characterized by the inadequate closure of the aortic valve, leading to blood flowing back from the aorta into the LV during diastole [22](#page=22).
* **Pathophysiology:**
* The backflow of blood into the LV during diastole increases the LV end-diastolic volume (EDV) [22](#page=22).
* This leads to LV dilation and eccentric hypertrophy [22](#page=22).
* In later stages, increased LV end-diastolic pressure (LVEDP) can cause pulmonary hypertension and heart failure [22](#page=22).
* **Causes:**
* **Acute:** Infective endocarditis (IE), trauma, aortic dissection, or failed valve surgery [22](#page=22).
* **Chronic:** Rheumatic heart disease, bicuspid aortic valve, connective tissue diseases (e.g., Marfan syndrome), syphilitic disease, aortic root disease, and hypertension [22](#page=22).
* **Clinical features:**
* Symptoms include dyspnea, PND, orthopnea, and angina [22](#page=22).
* A wide pulse pressure (difference between systolic and diastolic blood pressure) is characteristic [22](#page=22).
* An early diastolic decrescendo murmur is heard at the left sternal border [22](#page=22).
* Physical signs include Corrigan (water-hammer) pulse and an Austin Flint mid-diastolic rumble at the apex [22](#page=22).
* **Diagnosis:**
* **CXR:** May show cardiomegaly and a dilated aorta [22](#page=22).
* **ECG:** Can reveal LVH [22](#page=22).
* **Echocardiogram:** Assesses LV size and function, visualizes the regurgitant jet, and evaluates aortic root dilation [22](#page=22).
* **Cardiac Catheterization:** Used to quantify the severity of regurgitation prior to surgery [22](#page=22).
* **Treatment:**
* Observation is recommended for asymptomatic patients with normal LV size and function [22](#page=22).
* Vasodilators like ACE inhibitors or ARBs, diuretics, and heart failure therapies are used for symptomatic patients or those with LV dysfunction [22](#page=22).
* Definitive treatment is aortic valve replacement (AVR). Acute AR necessitates emergent AVR [22](#page=22).
#### 9.3.2 Mitral regurgitation (MR)
Mitral regurgitation occurs when the mitral valve fails to close properly, allowing blood to flow backward from the LV into the left atrium (LA) during systole [22](#page=22).
* **Pathophysiology:**
* During systole, blood flows back from the LV into the LA [22](#page=22).
* **Acute MR:** Causes a sudden increase in LA pressure (LAP), leading to pulmonary edema and shock [22](#page=22).
* **Chronic MR:** Results in LA and LV dilation, which can lead to LV dysfunction and pulmonary hypertension [22](#page=22).
* **Causes:**
* **Acute:** Infective endocarditis (IE), papillary muscle rupture or dysfunction, or chordae tendineae rupture [22](#page=22).
* **Chronic:** Mitral valve prolapse (MVP), rheumatic heart disease, Marfan syndrome, and dilated cardiomyopathy [22](#page=22).
* **Clinical features:**
* Symptoms include dyspnea, PND, orthopnea, and palpitations [22](#page=22).
* A holosystolic murmur is heard at the apex and may radiate to the axilla or back [22](#page=22).
* An S3 gallop and a displaced point of maximal impulse (PMI), often indicative of a forceful, brisk heartbeat felt on the chest, are common findings [22](#page=22).
* Atrial fibrillation is frequent due to LA dilation [22](#page=22).
* **Diagnosis:**
* **CXR:** May reveal cardiomegaly and pulmonary edema [22](#page=22).
* **Echocardiogram:** Demonstrates the regurgitant jet, LA and LV dilation, and reduced LV function [22](#page=22).
* **Treatment:**
* Vasodilators (ACE inhibitors/ARBs) are used for symptomatic patients [22](#page=22).
* Anticoagulation is indicated if atrial fibrillation is present [22](#page=22).
* Intra-aortic balloon pump (IABP) can serve as a bridge in cases of acute severe MR [22](#page=22).
* Mitral valve repair or replacement is recommended before significant LV dysfunction develops [22](#page=22).
---
# Valvular heart disease: tricuspid regurgitation and mitral valve prolapse
This section details two distinct valvular heart conditions: tricuspid regurgitation, often secondary to right ventricular dilation, and mitral valve prolapse, characterized by redundant mitral leaflets.
### 10.1 Tricuspid regurgitation (TR)
Tricuspid regurgitation is defined as the failure of the tricuspid valve (TV) to close properly during systole, leading to a backflow of blood from the right ventricle (RV) into the right atrium (RA) [23](#page=23).
#### 10.1.1 Causes of tricuspid regurgitation
TR is most commonly secondary to RV dilation. Common causes leading to RV dilation include [23](#page=23):
* Left ventricular (LV) failure, which can lead to pulmonary hypertension (PH) and subsequent RV strain [23](#page=23).
* RV infarction or inferior myocardial infarction (MI) [23](#page=23).
* Cor pulmonale, a condition caused by chronic lung disease leading to pulmonary hypertension and RV strain [23](#page=23).
Other causes of TR include:
* Tricuspid endocarditis, particularly in individuals who use intravenous drugs [23](#page=23).
* Rheumatic heart disease [23](#page=23).
* Ebstein anomaly, a congenital condition where the tricuspid valve is displaced downwards [23](#page=23).
* Other etiologies such as carcinoid syndrome, systemic lupus erythematosus (SLE), and myxomatous degeneration of the valve leaflets [23](#page=23).
#### 10.1.2 Clinical features of tricuspid regurgitation
Patients with TR are often asymptomatic. When symptoms are present, they are typically related to the consequences of RV failure or pulmonary hypertension. These can include fatigue, ascites, leg edema, and abdominal discomfort [23](#page=23).
Physical examination may reveal signs of RV failure, such as jugular venous distension (JVD), hepatomegaly (which may be pulsatile), peripheral edema, and ascites. The jugular venous pulse (JVP) can show prominent V waves and a rapid y descent. Auscultation may reveal a blowing holosystolic murmur best heard at the left lower sternal border (LLSB), which increases in intensity with inspiration (Carvallo sign). An inspiratory S3 sound may also be heard along the LLSB. Other signs can include an RV heave and, if the RA is significantly dilated, atrial fibrillation [23](#page=23).
#### 10.1.3 Diagnosis of tricuspid regurgitation
The diagnosis of TR is primarily established using an echocardiogram, which assesses the severity of regurgitation, any underlying leaflet pathology, and pulmonary pressures. An electrocardiogram (ECG) may show signs of RA and RV enlargement [23](#page=23).
#### 10.1.4 Treatment of tricuspid regurgitation
Treatment for TR focuses on addressing the underlying cause. This includes managing heart failure (HF), pulmonary hypertension (PH), and treating endocarditis if present. Diuretics are used to manage volume overload. Surgical intervention, such as repair or annuloplasty, is considered for severe TR when there is no significant pulmonary hypertension [23](#page=23).
### 10.2 Mitral valve prolapse (MVP)
Mitral valve prolapse (MVP) is defined as the redundant or myxomatous degeneration of the mitral valve (MV) leaflets and/or chordae, allowing them to prolapse into the left atrium (LA) during systole. This can be associated with a mid-systolic click and/or a mitral regurgitation (MR) murmur [23](#page=23).
#### 10.2.1 Associations with mitral valve prolapse
MVP is commonly associated with connective tissue disorders, including Marfan syndrome, Ehlers-Danlos syndrome, and osteogenesis imperfecta [23](#page=23).
#### 10.2.2 Clinical features of mitral valve prolapse
Patients with MVP are often asymptomatic. When symptoms occur, they may include palpitations, atypical chest pain, and anxiety. In rare cases, transient ischemic attacks (TIAs) can be a manifestation [23](#page=23).
Physical examination findings are dynamic and can change with posture. Characteristic findings include a mid-systolic click, which may be followed by a mid-to-late systolic murmur heard best at the apex. Maneuvers that decrease left ventricular (LV) volume, such as standing or performing a Valsalva maneuver, tend to cause the click and murmur to occur earlier and become louder. Conversely, maneuvers that increase LV volume, such as squatting, result in a later and softer click and murmur [23](#page=23).
> **Tip:** The classic presentation of MVP is often described as a young, thin, anxious woman with a mid-systolic click and a late-systolic murmur that changes with posture.
#### 10.2.3 Diagnosis of mitral valve prolapse
Diagnosis is confirmed by echocardiography, which demonstrates leaflet prolapse and can assess for the presence and severity of mitral regurgitation [23](#page=23).
#### 10.2.4 Treatment of mitral valve prolapse
For asymptomatic patients with MVP, reassurance is the primary management strategy. Beta-blockers may be prescribed to manage symptoms like palpitations and chest pain. Surgical intervention is rarely required and is typically reserved for cases where significant mitral regurgitation develops [23](#page=23).
---
# Cardiac inflammatory and valvular diseases
This topic details Rheumatic Heart Disease (RHD) and Infective Endocarditis (IE), two significant conditions affecting the heart's endocardial surface and valves.
### 11.1 Rheumatic heart disease (RHD)
#### 11.1.1 Origin and pathophysiology
Rheumatic heart disease (RHD) is a complication that arises from group A streptococcal pharyngitis. It is an immune-mediated sequela of acute rheumatic fever (ARF), which can lead to chronic valvular damage [24](#page=24) [25](#page=25).
#### 11.1.2 Main valve involvement
The mitral valve is the most commonly affected valve in RHD, often resulting in mitral stenosis. Involvement of the aortic or tricuspid valves may also occur [24](#page=24) [25](#page=25).
#### 11.1.3 Acute rheumatic fever diagnosis (JONES criteria)
Diagnosis of acute rheumatic fever (ARF) requires either two major criteria or one major and two minor criteria [24](#page=24) [25](#page=25).
* **Major criteria:**
* Migratory polyarthritis [24](#page=24) [25](#page=25).
* Carditis (pericarditis, congestive heart failure, or valvulitis) [24](#page=24) [25](#page=25).
* Erythema marginatum [24](#page=24) [25](#page=25).
* Chorea (Sydenham's chorea) [24](#page=24) [25](#page=25).
* Subcutaneous nodules [24](#page=24) [25](#page=25).
* **Minor criteria:**
* Fever [24](#page=24) [25](#page=25).
* Elevated erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) indicating acute phase reactants [24](#page=24) [25](#page=25).
* Polyarthralgia [24](#page=24) [25](#page=25).
* History of prior rheumatic fever [24](#page=24) [25](#page=25).
* Prolonged PR interval on electrocardiogram [24](#page=24) [25](#page=25).
* Evidence of preceding streptococcal infection (positive throat culture or elevated antistreptolysin O (ASO) titer) [24](#page=24) [25](#page=25).
#### 11.1.4 Treatment
Treatment strategies aim to prevent future episodes of rheumatic fever and manage existing valve damage [24](#page=24) [25](#page=25).
* **Prevention of RF:** Prompt and complete treatment of strep throat with penicillin is crucial [24](#page=24) [25](#page=25).
* **Treatment of ARF:** Non-steroidal anti-inflammatory drugs (NSAIDs) are used to manage ARF, and CRP levels are monitored [24](#page=24) [25](#page=25).
* **Treatment of chronic valve lesions:** This involves a combination of medical management and surgical valve therapy [24](#page=24) [25](#page=25).
#### 11.1.5 Epidemiology
RHD incidence has decreased in industrialized countries but remains a significant public health problem in developing nations [24](#page=24) [25](#page=25).
### 11.2 Infective endocarditis (IE)
#### 11.2.1 Definition
Infective endocarditis (IE) is defined as an infection of the endocardial surface of the heart, most commonly affecting the heart valves [24](#page=24) [25](#page=25).
#### 11.2.2 Types of IE
IE can be classified into acute and subacute forms:
* **Acute IE:** Typically caused by highly virulent organisms like *Staphylococcus aureus*. It often affects normal valves and can be fatal within six weeks if left untreated [24](#page=24) [25](#page=25).
* **Subacute IE:** Usually caused by less virulent organisms such as *Streptococcus viridans* or enterococci. It commonly affects pre-damaged valves and follows a slower clinical course [24](#page=24) [25](#page=25).
#### 11.2.3 Causative organisms
The microorganisms responsible for IE vary depending on the valve type and patient risk factors:
* **Native valve IE:** Common culprits include *Streptococcus viridans* (most common), *Staphylococcus* species, enterococci, HACEK organisms, and *Streptococcus bovis* [24](#page=24) [25](#page=25).
* **Prosthetic valve IE:**
* Early onset (within 60 days of surgery): Primarily caused by *Staphylococcus* species, especially *Staphylococcus epidermidis* [24](#page=24) [25](#page=25).
* Late onset (after 60 days): More commonly caused by streptococci [24](#page=24) [25](#page=25).
* **Intravenous drug users (IVDUs):** *Staphylococcus aureus* is a frequent pathogen, often affecting the right-sided valves, particularly the tricuspid valve [24](#page=24) [25](#page=25).
#### 11.2.4 Complications
IE can lead to several severe complications:
* Heart failure due to valvular destruction [24](#page=24) [25](#page=25).
* Paravalvular abscesses, which can lead to conduction defects such as atrioventricular (AV) block [24](#page=24) [25](#page=25).
* Septic emboli, which can lodge in various organs including the lungs, brain, kidneys, and spleen [24](#page=24) [25](#page=25).
* Glomerulonephritis, resulting from immune complex deposition [24](#page=24) [25](#page=25).
* Peripheral signs, including:
* Osler's nodes: Painful, palpable nodules on the digits [24](#page=24) [25](#page=25).
* Janeway lesions: Painless, erythematous or hemorrhagic macules on the palms and soles [24](#page=24) [25](#page=25).
* Roth spots: Flame-shaped retinal hemorrhages with pale centers [24](#page=24) [25](#page=25).
* Splinter hemorrhages: Thin, linear hemorrhages under the fingernails or toenails [24](#page=24) [25](#page=25).
#### 11.2.5 Diagnosis (Duke Criteria)
A definite diagnosis of IE is made if there are either two major criteria, one major and three minor criteria, or five minor criteria [24](#page=24) [25](#page=25).
* **Major criteria:**
* Typical positive blood cultures for infective endocarditis [24](#page=24) [25](#page=25).
* Evidence of endocardial involvement, confirmed by echocardiography showing vegetations, abscesses, dehiscence of prosthetic valves, or new valvular regurgitation [24](#page=24) [25](#page=25).
* **Minor criteria:**
* Presence of a predisposing heart condition or intravenous drug use [24](#page=24) [25](#page=25).
* Fever [24](#page=24) [25](#page=25).
* Vascular phenomena (e.g., arterial emboli, septic pulmonary infarcts, mycotic aneurysms, Janeway lesions) [24](#page=24) [25](#page=25).
* Immune phenomena (e.g., Osler's nodes, Roth's spots, glomerulonephritis, rheumatoid factor) [24](#page=24) [25](#page=25).
* Positive blood cultures that do not meet the major criterion [24](#page=24) [25](#page=25).
* Echocardiographic findings that do not meet the major criterion [24](#page=24) [25](#page=25).
#### 11.2.6 Treatment
The management of IE involves antimicrobial therapy and, in some cases, surgical intervention [24](#page=24) [25](#page=25).
* **Blood cultures:** Three sets of blood cultures should be drawn before initiating antibiotic therapy [24](#page=24) [25](#page=25).
* **Antibiotics:** Prolonged intravenous antibiotic therapy, typically lasting 4 to 6 weeks, is administered, with the choice of antibiotics guided by blood culture results [24](#page=24) [25](#page=25).
* **Device removal:** Infected intracardiac devices should be removed if possible [24](#page=24) [25](#page=25).
* **Early surgery is indicated if:**
* Acute heart failure develops due to valve damage [24](#page=24) [25](#page=25).
* Highly resistant or unusual organisms are identified [24](#page=24) [25](#page=25).
* Heart block or an intracardiac abscess is present [24](#page=24) [25](#page=25).
* Persistent bacteremia or fever continues for more than 5–7 days despite appropriate antibiotic therapy [24](#page=24) [25](#page=25).
* Recurrent infections occur in patients with prosthetic valves [24](#page=24) [25](#page=25).
#### 11.2.7 Prophylaxis
Antibiotic prophylaxis for IE is recommended only for patients who meet **both** of the following conditions [24](#page=24) [25](#page=25):
* **High-risk cardiac condition:**
* Prosthetic heart valves [24](#page=24) [25](#page=25).
* Previous history of infective endocarditis [24](#page=24) [25](#page=25).
* Certain types of congenital heart disease (CHD) [24](#page=24) [25](#page=25).
* Cardiac transplant recipients with valvulopathy [24](#page=24) [25](#page=25).
* **High-risk procedure:**
* Dental procedures involving manipulation of the gingiva or periapical region of teeth, or perforation of the oral mucosa [24](#page=24) [25](#page=25).
* Invasive procedures involving incision or biopsy of respiratory tract mucosa [24](#page=24) [25](#page=25).
* Procedures on infected skin or musculoskeletal tissue [24](#page=24) [25](#page=25).
Prophylaxis is **not** recommended for patients with native mitral valve prolapse (MVP) or stenosis, nor for routine gastrointestinal or genitourinary procedures [24](#page=24) [25](#page=25).
---
# Vascular disease: aortic dissection and abdominal aortic aneurysm
This section covers two critical vascular conditions: aortic dissection, characterized by a tear in the aorta's inner lining, and abdominal aortic aneurysms (AAAs), defined as localized dilations of the abdominal aorta.
### 12.1 Aortic dissection
#### 12.1.1 Definition
Aortic dissection occurs when there is a tear in the intima, allowing blood to enter and create a false lumen within the media of the aortic wall, leading to the aorta essentially "peeling" apart. This is often described as a tear in the artery, akin to paper being torn lengthwise [26](#page=26) [27](#page=27).
#### 12.1.2 Risk factors
Several factors predispose individuals to aortic dissection:
* **Hypertension (HTN):** Long-standing hypertension is the most common risk factor, present in approximately 70% of cases [26](#page=26) [27](#page=27).
* **Substance Use:** Cocaine use is a significant risk factor [26](#page=26) [27](#page=27).
* **Trauma:** Blunt or penetrating trauma can lead to dissection [26](#page=26) [27](#page=27).
* **Connective Tissue Diseases:** Conditions like Marfan syndrome and Ehlers-Danlos syndrome weaken the aortic wall [26](#page=26) [27](#page=27).
* **Congenital Heart Defects:** A bicuspid aortic valve and coarctation of the aorta are associated risks [26](#page=26) [27](#page=27).
* **Pregnancy:** The third trimester of pregnancy increases risk [26](#page=26) [27](#page=27).
* **Pre-existing Aortic Aneurysm:** A known aneurysm is a risk factor [26](#page=26) [27](#page=27).
* **Atherosclerosis:** An intimal ulceration resulting from atherosclerosis can initiate dissection [26](#page=26) [27](#page=27).
#### 12.1.3 Stanford classification
The Stanford classification is a widely used system for categorizing aortic dissections:
* **Type A:** Involves the ascending aorta and may extend to the aortic arch. This type requires surgical intervention [26](#page=26) [27](#page=27).
* **Type B:** Involves the descending aorta distal to the left subclavian artery. This type is typically managed medically [26](#page=26) [27](#page=27).
#### 12.1.4 Clinical features
Patients with aortic dissection often present with dramatic and severe symptoms:
* **Pain:** Sudden, severe "tearing" or "ripping" chest or back pain is characteristic. Anterior chest pain suggests a Type A dissection, while interscapular back pain is more typical of Type B [26](#page=26) [27](#page=27).
* **Autonomic Symptoms:** Diaphoresis (sweating) is common [26](#page=26) [27](#page=27).
* **Hemodynamics:** Hypertension is often present, though hypotension can occur, particularly if rupture or tamponade is present [26](#page=26) [27](#page=27).
* **Asymmetry:** A pulse or blood pressure asymmetry between limbs can be a key finding [26](#page=26) [27](#page=27).
* **Aortic Regurgitation:** An aortic regurgitation murmur may be heard, especially in proximal dissections [26](#page=26) [27](#page=27).
* **Neurologic Deficits:** Symptoms suggestive of stroke, such as focal neurologic deficits, can occur due to compromised blood flow to the brain [26](#page=26) [27](#page=27).
* **Complications:** Dissection can extend and lead to myocardial infarction (MI) or cardiac tamponade. The superacute and dramatic nature of dissection means it can be rapidly fatal [26](#page=26) [27](#page=27).
#### 12.1.5 Diagnosis
Diagnostic tools are crucial for identifying aortic dissection:
* **Chest X-ray (CXR):** May reveal a widened mediastinum [26](#page=26) [27](#page=27).
* **CT Angiogram (CTA):** This is the primary diagnostic test in the emergency department due to its speed and accuracy [26](#page=26) [27](#page=27).
* **Transesophageal Echocardiogram (TEE):** Offers high sensitivity and specificity, can be performed at the bedside, and is valuable for unstable patients [26](#page=26) [27](#page=27).
* **Magnetic Resonance Imaging (MRI):** Accurate but slower, making it more suitable for stable patients [26](#page=26) [27](#page=27).
* **Aortic Angiography:** Historically the gold standard, it is now mainly used for interventional procedures [26](#page=26) [27](#page=27).
#### 12.1.6 Management
Management strategies depend on the type of dissection:
* **Immediate Medical Management:**
* Administer intravenous beta-blockers (e.g., labetalol, esmolol) to control heart rate and blood pressure [26](#page=26) [27](#page=27).
* Target a systolic blood pressure (SBP) between 100–120 mmHg [26](#page=26) [27](#page=27).
* If blood pressure remains elevated despite beta-blockers, nitroprusside can be added [26](#page=26) [27](#page=27).
* Strong analgesia, such as morphine, is essential for pain management [26](#page=26) [27](#page=27).
* **Type A Dissection:** Requires emergency surgical repair, typically via an open procedure [26](#page=26) [27](#page=27).
* **Type B Dissection:** Managed with continued medical therapy, including intravenous beta-blockers and analgesia. Surgery or endovascular repair may be considered if complications arise or pain persists [26](#page=26) [27](#page=27).
### 12.2 Abdominal aortic aneurysm (AAA)
#### 12.2.1 Definition and site
An abdominal aortic aneurysm (AAA) is a localized dilation of the abdominal aorta, typically occurring between the renal arteries and the bifurcation into the iliac arteries. It can be conceptualized as the aorta being "pregnant" in the abdomen [26](#page=26) [27](#page=27).
#### 12.2.2 Epidemiology
* **Age:** Most commonly seen in individuals over 50 years old, with a peak incidence between 65 and 70 years [26](#page=26) [27](#page=27).
* **Sex:** AAAs are more common in men [26](#page=26) [27](#page=27).
* **Rupture Risk:** Notably, the risk of rupture for a given size is higher in women compared to men [26](#page=26) [27](#page=27).
#### 12.2.3 Causes and risk factors
The primary cause of AAAs is the atherosclerotic weakening of the aortic wall. Other contributing factors include [26](#page=26) [27](#page=27):
* **Hypertension (HTN):** Elevated blood pressure contributes to aortic wall stress [26](#page=26) [27](#page=27).
* **Smoking:** A significant and modifiable risk factor [26](#page=26) [27](#page=27).
* **Trauma:** Injury to the aorta can lead to aneurysm formation [26](#page=26) [27](#page=27).
* **Vasculitis:** Inflammation of blood vessels can weaken the aorta [26](#page=26) [27](#page=27).
* **Family History:** A positive family history increases risk [26](#page=26) [27](#page=27).
* **Infections and CTDs:** While less common for AAAs, syphilis and connective tissue diseases (like Marfan syndrome) can cause aneurysms, though they are more frequently associated with thoracic involvement and can extend to the lower aorta [26](#page=26) [27](#page=27).
#### 12.2.4 Clinical features
AAAs are often asymptomatic and discovered incidentally:
* **Asymptomatic:** Many patients are unaware they have an AAA [26](#page=26) [27](#page=27).
* **Vague Symptoms:** Some may experience vague abdominal or low back "fullness" or a throbbing sensation [26](#page=26) [27](#page=27).
* **Palpable Mass:** A pulsatile abdominal mass may be detected on physical examination [26](#page=26) [27](#page=27).
* **Expansion or Impending Rupture:** As the aneurysm grows or is on the verge of rupture, symptoms become more severe:
* Sudden, severe back or lower abdominal pain.
* Pain may radiate to the groin, buttocks, or legs.
* **Grey-Turner sign:** Ecchymoses (bruising) in the flanks [26](#page=26) [27](#page=27).
* **Cullen sign:** Periumbilical ecchymoses [26](#page=26) [27](#page=27).
* **Ruptured AAA:** This is a life-threatening emergency presenting with:
* Severe abdominal or back pain.
* Hypotension and signs of shock.
* A palpable pulsatile abdominal mass may still be present. Ruptured AAAs can lead to cardiovascular collapse [26](#page=26) [27](#page=27).
#### 12.2.5 Diagnosis
* **Ultrasound:** Highly sensitive (approximately 100%) and is used for screening and measuring aneurysm size [26](#page=26) [27](#page=27).
* **CT Scan:** Also has approximately 100% sensitivity and is the scan of choice for preoperative planning in hemodynamically stable patients [26](#page=26) [27](#page=27).
#### 12.2.6 Treatment
Treatment decisions for AAAs are based on size, symptoms, and the presence of rupture:
* **Unruptured AAA:**
* **Surgical Repair:** Recommended for aneurysms greater than or equal to 5 cm in diameter or those that are symptomatic. This can be achieved via open surgical repair or endovascular aneurysm repair (EVAR) [26](#page=26) [27](#page=27).
* **Surveillance:** For aneurysms smaller than 5 cm and asymptomatic, regular surveillance imaging is employed [26](#page=26) [27](#page=27).
* **Consider Repair:** Aneurysms showing rapid growth (more than 1 cm per year) should also be considered for repair [26](#page=26) [27](#page=27).
* **Ruptured AAA:** This is a surgical emergency requiring immediate intervention, typically open repair, though EVAR may be an option in selected patients [26](#page=26) [27](#page=27).
---
# Hypertensive emergencies and small vascular topics
This topic covers the critical condition of hypertensive emergency, differentiating it from urgency, outlining its target organ damage, causes, clinical features, and treatment, alongside brief discussions on cholesterol embolization syndrome, mycotic aneurysms, and luetic heart disease.
### 13.1 Hypertensive emergency
#### 13.1.1 Definition
Hypertensive emergency is defined by a blood pressure of **≥180 mmHg systolic** and/or **≥120 mmHg diastolic**, accompanied by acute end-organ damage affecting the brain, heart, kidneys, eyes, or lungs [28](#page=28).
#### 13.1.2 Hypertensive urgency vs. hypertensive emergency
Hypertensive urgency shares the same blood pressure range (≥180/120 mmHg) but crucially **lacks acute end-organ damage**. Treatment for urgency typically involves oral medications and is managed over 24 hours, whereas emergencies require immediate intervention [28](#page=28).
#### 13.1.3 Target organs and damage
The following organs are susceptible to damage in a hypertensive emergency:
* **Central Nervous System (CNS):** Encephalopathy, intracranial hemorrhage (ICH), and posterior reversible encephalopathy syndrome (PRES) [28](#page=28).
* **Eyes:** Papilledema and retinal hemorrhages [28](#page=28).
* **Heart:** Unstable angina, myocardial infarction (MI), acute left ventricular (LV) failure, and aortic dissection [28](#page=28).
* **Kidneys:** Acute kidney injury (AKI) and oliguria [28](#page=28).
* **Lungs:** Pulmonary edema [28](#page=28).
#### 13.1.4 Causes
Common causes of hypertensive emergencies, summarized by the mnemonic "HYPER-BP," include:
* **Non-compliance:** Patients not taking their antihypertensive medications or skipping dialysis [28](#page=28).
* **Drugs:** Use of substances like cocaine, LSD, and methamphetamines [28](#page=28).
* **Endocrine:** Conditions such as pheochromocytoma, hyperaldosteronism, Cushing's syndrome, and eclampsia [28](#page=28).
* **Vascular/Renal:** Atherosclerotic plaque rupture, vasculitis, renal artery stenosis, and polycystic kidney disease (PKD) [28](#page=28).
* **Other:** Alcohol withdrawal and various other less common etiologies [28](#page=28).
#### 13.1.5 Clinical features
Patients presenting with a hypertensive emergency may exhibit:
* Severe headache and visual disturbances [28](#page=28).
* Altered mental status, confusion, or seizures [28](#page=28).
* Symptoms indicative of specific organ failure, such as chest pain, dyspnea, oliguria, or focal neurological deficits [28](#page=28).
#### 13.1.6 Treatment
The primary goal of treatment is to reduce the mean arterial pressure (MAP) by approximately 25% within the first 1-2 hours, without normalizing it completely [28](#page=28).
* **Intravenous (IV) Agents:** Medications commonly used include labetalol, esmolol, nicardipine, nitroprusside, nitroglycerin, and hydralazine [28](#page=28).
* **Gradual Reduction:** Following initial stabilization, blood pressure should be gradually reduced over the subsequent 24–48 hours [28](#page=28).
* **Hypertensive Urgency:** For hypertensive urgency, oral agents such as captopril, clonidine, labetalol, or nifedipine are typically employed [28](#page=28).
### 13.2 Cholesterol embolization syndrome
#### 13.2.1 Pathology
This syndrome occurs due to "showers" of cholesterol crystals dislodging from atherosclerotic plaques, most commonly found in the aorta, iliac arteries, or femoral arteries [28](#page=28).
#### 13.2.2 Triggers
Common triggers for cholesterol embolization include:
* Vascular procedures such as angiography, stent placement, or surgery [28](#page=28).
* Thrombolytic therapy [28](#page=28).
#### 13.2.3 Clinical manifestations
Patients may present with:
* Characteristic "blue/black toes" and livedo reticularis [28](#page=28).
* Renal insufficiency [28](#page=28).
* Abdominal pain and bleeding, indicative of intestinal hypoperfusion [28](#page=28).
#### 13.2.4 Management
Management is primarily supportive, focusing on controlling blood pressure. Anticoagulation is generally avoided unless a clear thrombus is present. Surgical intervention or amputation is reserved for severe, non-resolving cases [28](#page=28).
### 13.3 Mycotic aneurysm
#### 13.3.1 Definition
A mycotic aneurysm is characterized by the infectious destruction of an arterial wall, leading to the formation of a focal aneurysm. Despite the name, it is usually bacterial in origin, often stemming from endocarditis or bacteremia [28](#page=28).
#### 13.3.2 Features
Key features include positive blood cultures, and the presence of a localized, painful, and expanding aneurysm [28](#page=28).
#### 13.3.3 Treatment
Treatment involves a combination of intravenous antibiotics and surgical excision or repair of the affected artery [28](#page=28).
### 13.4 Luetic heart
#### 13.4.1 Pathophysiology
Luetic heart disease refers to complications arising from tertiary syphilitic aortitis. This condition can lead to an aneurysm of the ascending aortic arch [28](#page=28).
#### 13.4.2 Manifestations
The aortic arch aneurysm can extend retrogradely, causing aortic regurgitation. It can also lead to stenosis of the aortic branch ostia, resulting in coronary artery ischemia and ischemia of other branches [28](#page=28).
#### 13.4.3 Treatment
Management consists of intravenous penicillin administration, along with surgical repair of the aneurysm and any affected valves [28](#page=28).
---
# Peripheral arterial disease and acute arterial occlusion
Peripheral arterial disease (PAD) refers to chronic atherosclerotic narrowing of lower-extremity arteries, while acute arterial occlusion (AAO) is a sudden blockage, typically due to an embolus [29](#page=29).
### 14.1 Peripheral arterial disease (PAD)
#### 14.1.1 Definition
Peripheral arterial disease is defined as the chronic atherosclerotic narrowing of the arteries in the lower extremities. This gradual narrowing impacts blood flow over time [29](#page=29).
#### 14.1.2 Sites
The most common sites for PAD include the superficial femoral artery (specifically in Hunter's canal), the popliteal artery, and the aortoiliac arteries [29](#page=29).
#### 14.1.3 Risk factors
The primary risk factors for PAD can be remembered by the mnemonic "SAD" [29](#page=29):
* **S**moking: This is the strongest risk factor [29](#page=29).
* **A**therosclerotic buddies: This includes co-existing cardiovascular disease (CAD), hypertension (HTN), and hyperlipidemia [29](#page=29).
* **D**iabetes mellitus: This is also a significant risk factor [29](#page=29).
> **Tip:** PAD often signifies widespread atherosclerosis, meaning patients with PAD likely have underlying issues in their entire vasculature, not just their legs [29](#page=29).
#### 14.1.4 Pathophysiology
The atherosclerotic plaque gradually narrows the arterial lumen, leading to reduced blood flow, particularly during exertion. As the disease progresses, rest blood flow is also compromised, which can manifest as rest pain, ulcers, and even gangrene [29](#page=29).
#### 14.1.5 Clinical features
PAD presents with both symptoms and signs [29](#page=29).
##### 14.1.5.1 Symptoms
* **Intermittent claudication:** This is characterized by calf pain that occurs with exertion and is relieved by rest [29](#page=29).
* **Rest pain:** This is a more severe symptom, typically affecting the distal foot and worsening at night. Patients may find relief by hanging their leg off the bed, which utilizes gravity to improve blood flow [29](#page=29).
##### 14.1.5.2 Signs
* Diminished or absent pulses in the affected limb [29](#page=29).
* Atrophy of muscles, hair loss on the skin, and a shiny, cool skin appearance [29](#page=29).
* Ischemic ulcers, most commonly found on the toes [29](#page=29).
* In advanced cases, pallor of the limb when elevated and a dusky red (rubor) color when dependent [29](#page=29).
#### 14.1.6 Diagnosis
The diagnosis of PAD relies on several methods [29](#page=29).
* **Ankle-brachial index (ABI):** This is a crucial diagnostic tool [29](#page=29).
* Normal ABI is between 0.9 and 1.3 [29](#page=29).
* An ABI less than 0.7 is indicative of claudication [29](#page=29).
* An ABI less than 0.4 suggests critical limb ischemia and rest pain [29](#page=29).
* **Caution with ABI >1.3:** An ABI greater than 1.3 suggests non-compressible vessels due to calcification, often seen in patients with diabetes mellitus [29](#page=29).
* **Pulse volume recordings (PVRs):** These can provide further information about blood flow [29](#page=29).
* **Arteriography:** Techniques like computed tomography angiography (CTA), magnetic resonance angiography (MRA), or traditional angiograms are considered the gold standard for pre-operative planning, especially for surgical interventions [29](#page=29).
#### 14.1.7 Treatment
Treatment for PAD involves both conservative and interventional approaches [29](#page=29).
##### 14.1.7.1 Conservative management
* **Smoking cessation:** Essential for slowing disease progression [29](#page=29).
* **Exercise program:** A structured program, often involving a "walk-rest-walk" protocol, can improve walking distance [29](#page=29).
* **Foot care and risk factor control:** Meticulous foot hygiene and management of other risk factors (HTN, hyperlipidemia, diabetes) are vital [29](#page=29).
* **Antiplatelet therapy:** Aspirin, often in combination with clopidogrel, is used to prevent thrombotic events [29](#page=29).
* **Cilostazol:** This medication can be prescribed specifically for claudication symptoms but should be avoided in patients with heart failure [29](#page=29).
##### 14.1.7.2 Surgical/Endovascular management
Indications for intervention include rest pain, ulcers, tissue loss, or disabling claudication [29](#page=29).
* **Angioplasty with or without stenting:** This endovascular approach aims to open narrowed arteries [29](#page=29).
* **Bypass grafts:** Surgical procedures such as femoropopliteal (fem-pop) or aortofemoral bypass grafts reroute blood flow around occluded segments [29](#page=29).
### 14.2 Acute arterial occlusion (AAO)
#### 14.2.1 Definition
Acute arterial occlusion is defined as the sudden blockage of an artery, most frequently caused by an embolus, often affecting the arteries of the lower extremities. This is a rapid process, unlike the slow choking of PAD [29](#page=29).
#### 14.2.2 Causes
The most common cause of AAO is an embolus originating from the heart (approximately 85% of cases). Potential cardiac sources include [29](#page=29):
* Atrial fibrillation (AFib) [29](#page=29).
* Recent myocardial infarction (MI) [29](#page=29).
* Endocarditis [29](#page=29).
* Post-angiogram complications [29](#page=29).
* Cardiac myxoma (a benign tumor of the heart) [29](#page=29).
Other less common causes include arterial aneurysms or in-situ thrombosis (blood clot formation) over an existing atherosclerotic plaque [29](#page=29).
#### 14.2.3 Clinical features – "6 Ps"
The clinical presentation of AAO is characterized by the "6 Ps," which indicate severe limb ischemia [29](#page=29).
* **Pain:** Sudden and severe onset [29](#page=29).
* **Pallor:** The affected limb becomes pale [29](#page=29).
* **Polar (cold):** The limb feels chilled compared to other extremities [29](#page=29).
* **Pulselessness:** Absence of distal pulses in the affected limb [29](#page=29).
* **Paresthesias:** Tingling or numbness in the limb [29](#page=29).
* **Paralysis:** Loss of motor function; this is a late and ominous sign indicating significant muscle necrosis [29](#page=29).
> **Example:** A patient presents with sudden, severe pain in their calf and foot, which is cold, pale, and pulseless. They also report numbness and tingling. This constellation of symptoms strongly suggests acute arterial occlusion [29](#page=29).
#### 14.2.4 Diagnosis
AAO is a clinical emergency requiring prompt diagnosis and treatment [29](#page=29).
* **Arteriogram (CTA or invasive):** This is essential to precisely define the site and extent of the occlusion [29](#page=29).
* **ECG:** To assess for potential cardiac causes like AFib or MI [29](#page=29).
* **Echocardiogram:** To search for intracardiac sources of emboli, such as valvular vegetations or mural thrombi [29](#page=29).
#### 14.2.5 Treatment
The goal of treatment is to restore blood flow as quickly as possible, as muscle tissue can tolerate ischemia for approximately 6 hours before irreversible damage occurs [29](#page=29).
* **Immediate IV heparin:** Anticoagulation is started immediately to prevent further clot propagation and to facilitate potential thrombolysis [29](#page=29).
* **Emergent surgical embolectomy:** This is the mainstay of treatment, typically performed using a Fogarty balloon catheter to retrieve the embolus [29](#page=29).
* **Thrombolytics:** Intra-arterial thrombolytic therapy may be considered in selected cases, especially if surgical intervention is delayed or high-risk [29](#page=29).
* **Management of complications:** Close monitoring and management of potential complications, such as compartment syndrome, are crucial [29](#page=29).
---
# Deep venous thrombosis (DVT)
Deep venous thrombosis (DVT) refers to the formation of a blood clot within a deep vein, most commonly in the legs, which can lead to serious complications [30](#page=30).
### 15.1 Pathophysiology: Virchow's triad
The pathophysiology of DVT is best understood through Virchow's triad, which identifies three primary contributing factors [30](#page=30):
* **Venous stasis:** Slow blood flow in the veins, often due to immobility, congestive heart failure (CHF), obesity, or pregnancy [30](#page=30).
* **Intimal injury:** Damage to the inner lining of the blood vessel, which can be caused by surgery, trauma, a history of DVT, or the presence of catheters [30](#page=30).
* **Hypercoagulability:** An increased tendency for blood to clot, associated with malignancy, thrombophilias (such as Factor V Leiden mutation, protein C or S deficiency, or antithrombin III deficiency), and estrogen use (e.g., oral contraceptives, pregnancy) [30](#page=30).
> **Tip:** Remember Virchow's triad as the three pillars leading to DVT: stasis, injury, and hypercoagulability.
### 15.2 Risk factors
DVT is associated with several risk factors, often summarized by the mnemonic "HOT CAMP" [30](#page=30):
* **H**ormones: Oral contraceptive pills (OCPs), pregnancy, hormone replacement therapy (HRT) [30](#page=30).
* **O**lder age: Generally considered over 60 years old [30](#page=30).
* **T**rauma or major surgery: Particularly orthopedic or pelvic surgeries [30](#page=30).
* **C**ancer: Underlying malignancy increases risk [30](#page=30).
* **A** previous DVT or pulmonary embolism (PE), or varicose veins [30](#page=30).
* **M**edical immobilization: Including prolonged bed rest, CHF, or obesity [30](#page=30).
* **P**rocoagulant states: Inherited or acquired conditions that promote clotting [30](#page=30).
### 15.3 Clinical features
#### 15.3.1 Symptoms
Patients with DVT typically present with:
* Unilateral leg pain [30](#page=30).
* Swelling of the affected limb [30](#page=30).
* Symptoms that are often exacerbated by standing or walking and relieved by elevation [30](#page=30).
#### 15.3.2 Signs
Physical examination may reveal:
* Warmth and erythema (redness) of the affected leg [30](#page=30).
* Tenderness, particularly in the calf [30](#page=30).
* Homans' sign (calf pain with dorsiflexion of the foot) is an unreliable test and not routinely used [30](#page=30).
> **Tip:** While Homans' sign is mentioned, its low sensitivity and specificity mean it's not a definitive diagnostic tool for DVT.
#### 15.3.3 Complications
The potential complications of DVT are significant:
* **Pulmonary embolism (PE):** The most feared complication, occurring when a clot dislodges and travels to the lungs [30](#page=30).
* **Post-thrombotic syndrome (PTS):** Chronic venous insufficiency that can develop after a DVT, leading to long-term pain, swelling, and skin changes [30](#page=30).
* **Phlegmasia cerulea dolens:** A rare but severe form of DVT characterized by massive, painful, blue discoloration of the leg due to extensive venous occlusion and impaired arterial inflow [30](#page=30).
### 15.4 Diagnosis
Diagnosing DVT involves a stepwise approach, considering clinical probability and diagnostic testing:
#### 15.4.1 Clinical probability assessment
Tools like the Wells score are used to estimate the pre-test probability of DVT [30](#page=30).
#### 15.4.2 Imaging modalities
* **Duplex Doppler ultrasound:** This is the first-line diagnostic test and is particularly effective for diagnosing proximal DVT (femoral or popliteal veins) [30](#page=30).
* **Venography:** An invasive procedure considered the gold standard for diagnosing calf DVT, but less commonly used now due to the availability of ultrasound [30](#page=30).
* **Impedance plethysmography:** A noninvasive alternative that measures changes in electrical resistance to assess venous outflow; its use has decreased [30](#page=30).
#### 15.4.3 D-dimer
* **D-dimer** is a fibrin degradation product. A negative D-dimer in a patient with low pre-test probability effectively rules out DVT [30](#page=30).
* A positive D-dimer result necessitates further imaging, such as ultrasound, to confirm or exclude the diagnosis [30](#page=30).
#### 15.4.4 Diagnostic strategy
The general diagnostic strategy is as follows [30](#page=30):
* For patients with high or moderate clinical probability of DVT, proceed directly to ultrasound, possibly with repeat imaging or venography if initial results are inconclusive.
* For patients with low clinical probability, a D-dimer test is performed. If the D-dimer is positive, ultrasound is then performed.
### 15.5 Treatment
The treatment of DVT aims to prevent clot extension, reduce the risk of PE, and minimize the chances of developing post-thrombotic syndrome.
#### 15.5.1 Anticoagulation
Anticoagulation is the mainstay of DVT treatment [30](#page=30).
* **Low molecular weight heparin (LMWH)** (e.g., enoxaparin, dalteparin) or **Direct Oral Anticoagulants (DOACs)** are commonly used [30](#page=30).
* **Warfarin** can also be used, typically initiated with a heparin bridge (LMWH or unfractionated heparin) to achieve therapeutic anticoagulation. The target International Normalized Ratio (INR) for warfarin is usually 2–3, and treatment duration is typically 3 to 6 months [30](#page=30).
> **Tip:** Remember that LMWH is often preferred for initial anticoagulation due to its predictable pharmacokinetics and ease of administration, and it commonly requires a transition to warfarin.
#### 15.5.2 Thrombolysis
Thrombolysis (clot-dissolving therapy) is generally reserved for cases of massive PE and is not the routine treatment for DVT [30](#page=30).
#### 15.5.3 Inferior vena cava (IVC) filter
An IVC filter may be considered in specific situations:
* When there is a contraindication to anticoagulation [30](#page=30).
* In cases of recurrent PE despite adequate anticoagulation [30](#page=30).
#### 15.5.4 Prophylaxis
Prophylaxis against DVT is crucial for patients at risk, such as those undergoing surgery or experiencing immobility [30](#page=30).
* **Mechanical prophylaxis** includes early ambulation, compression stockings, and pneumatic compression boots [30](#page=30).
* **Pharmacologic prophylaxis** typically involves low-dose unfractionated heparin (UFH) or LMWH [30](#page=30).
### 15.6 Exam bait
Key points frequently tested on DVT include:
* Virchow's triad and its components [30](#page=30).
* The comprehensive list of risk factors [30](#page=30).
* The role of duplex ultrasound as the initial diagnostic test [30](#page=30).
* The utility of the D-dimer test for ruling out DVT in low-risk individuals [30](#page=30).
* Pulmonary embolism as the primary feared complication of DVT [30](#page=30).
* The benefits of LMWH and the necessity of bridging therapy when transitioning to warfarin [30](#page=30).
---
# Chronic venous insufficiency and superficial thrombophlebitis
This section details chronic venous insufficiency, a condition arising from damaged venous valves leading to venous hypertension and skin changes, and superficial thrombophlebitis, characterized by inflammation and clot formation in superficial veins.
### 16.1 Chronic venous insufficiency (CVI)
Chronic venous insufficiency, also known as postphlebitic syndrome, results from damage to deep and perforator venous valves. This damage leads to ambulatory venous hypertension, causing edema, skin damage, and ultimately, ulcers [31](#page=31).
#### 16.1.1 Pathophysiology
The core issue in CVI is the destruction of deep venous valves. This prevents proper unidirectional blood flow against gravity towards the heart, causing blood to pool in the lower extremities. When perforator valves, which connect superficial to deep veins, also fail, high pressure is transmitted to the superficial venous system. This sustained high pressure results in ambulatory venous hypertension, leading to several consequences [31](#page=31):
* **Fluid leakage:** Increased pressure forces fluid out of capillaries, causing edema [31](#page=31).
* **Red blood cell and protein leakage:** These components also leak into the surrounding tissues, leading to the deposition of hemosiderin, which causes the characteristic brown skin pigmentation [31](#page=31).
* **Fibrosis:** Chronic inflammation and tissue damage result in fibrosis, giving the skin a "brawny induration" appearance [31](#page=31).
* **Impaired capillary flow:** Reduced blood flow through capillaries compromises tissue oxygenation and nutrient supply, hindering wound healing and predisposing to ulcer formation, typically located just above the medial malleolus [31](#page=31).
> **Tip:** Remember the sequence: old deep vein thrombosis (DVT) leads to damaged valves, which causes ambulatory venous hypertension, resulting in edema, skin changes, and ulcers. This is a classic exam pathway [31](#page=31).
#### 16.1.2 Clinical features
**Symptoms** of CVI commonly include leg swelling, a feeling of heaviness or tightness, which are exacerbated by prolonged standing or sitting and relieved by leg elevation [31](#page=31).
**Signs** include:
* Pitting edema [31](#page=31).
* Skin that appears thin, shiny, and atrophic [31](#page=31).
* Brown-black pigmentation and brawny induration [31](#page=31).
* Venous ulcers, characteristically found just above the medial malleolus [31](#page=31).
> **Exam Bait:** A patient presenting with ulcers on the medial malleolus, brown, indurated skin, and relief of symptoms with leg elevation should strongly suggest CVI rather than peripheral artery disease (PAD) [31](#page=31).
#### 16.1.3 Treatment
Treatment strategies differ based on the presence of ulcers.
**Before ulcers develop:**
* **Leg elevation:** This is crucial and should be done both day and night [31](#page=31).
* **Activity modification:** Avoid prolonged periods of standing or sitting [31](#page=31).
* **Compression stockings:** Knee-length compression stockings are recommended [31](#page=31).
**With ulcers present:**
* **Dressings:** Wet-to-dry dressings are a common initial approach [31](#page=31).
* **Unna boot:** This zinc oxide paste-impregnated bandage can be applied weekly for compression and wound management [31](#page=31).
* **Advanced therapies:** For resistant ulcers, split-thickness skin grafts, sometimes combined with perforator ligation, may be considered [31](#page=31).
### 16.2 Superficial thrombophlebitis
Superficial thrombophlebitis involves inflammation and a clot forming within a superficial vein. It most commonly occurs in the upper limb, often associated with an intravenous cannula site, or in the lower limb, frequently within varicose veins, particularly the great saphenous vein. While Virchow's triad (stasis, hypercoagulability, endothelial injury) is implicated, the exact pathophysiology is not fully understood [31](#page=31).
#### 16.2.1 Clinical features
The presentation is typically localized and includes:
* Pain and tenderness along the affected vein [31](#page=31).
* Erythema (redness) over the vein [31](#page=31).
* Induration (hardening) of the vein segment [31](#page=31).
* A palpable, tender cord-like structure along the course of the vein [31](#page=31).
Systemic symptoms are usually minimal [31](#page=31).
> **Example:** A patient might complain of a painful, red, and swollen segment of their great saphenous vein, feeling like a hard, tender rope under the skin [31](#page=31).
> **Exam Bait:** Differentiating superficial thrombophlebitis from cellulitis or lymphangitis is important. Superficial thrombophlebitis is characterized by a palpable, localized, cord-like structure, whereas cellulitis presents with diffuse redness and lacks a distinct cord [31](#page=31).
#### 16.2.2 Treatment
**Anticoagulation:** Generally, anticoagulation is **not** indicated for uncomplicated superficial thrombophlebitis unless there is evidence of extension into the deep venous system [31](#page=31).
**Supportive care:**
* **Pain relief:** Non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin can be used [31](#page=31).
* **Elevation:** Elevating the affected limb can help reduce swelling [31](#page=31).
* **Warm compresses:** Applying warm compresses can provide symptomatic relief [31](#page=31).
* **Activity:** Patients are usually encouraged to continue their normal activities as tolerated [31](#page=31).
**Suppurative form:** In rare cases where the thrombophlebitis becomes infected (suppurative), the intravenous line should be removed (if applicable), and systemic antibiotics are required [31](#page=31).
---
# Congenital heart defects: ASD and VSD
This section details atrial septal defects (ASD) and ventricular septal defects (VSD), focusing on their types, pathophysiology, clinical presentations, diagnostic approaches, potential complications, and management strategies.
### 17.1 Atrial septal defect (ASD)
#### 17.1.1 Definition and types
An atrial septal defect (ASD) is a congenital heart defect characterized by an abnormal opening in the septum between the left atrium (LA) and the right atrium (RA). The most common type is the ostium secundum defect, which occurs in the mid-septum. Other types include ostium primum defects, associated with the lower septum and atrioventricular canal defects, and sinus venosus defects, located in the high septum near the superior vena cava [32](#page=32).
#### 17.1.2 Pathophysiology
The pathophysiology of ASD primarily involves a left-to-right (L-R) shunt, where blood flows from the higher-pressure left atrium to the lower-pressure right atrium. This results in an increased volume load on the right atrium and right ventricle, leading to their dilation. Consequently, there is increased pulmonary blood flow. In the late stages, if pulmonary vascular resistance increases significantly, pulmonary hypertension can develop, potentially leading to a reversal of the shunt (right-to-left or R-L) and cyanosis, a condition known as Eisenmenger syndrome [32](#page=32).
> **Tip:** The key principle in ASD is the L-R shunt through the atria, leading to volume overload on the right side of the heart and lungs.
#### 17.1.3 Clinical features
Many individuals with ASD are asymptomatic until adulthood. When symptoms do occur, they may include dyspnea (shortness of breath), fatigue, and a reduced exercise tolerance. Palpitations, often due to atrial arrhythmias like atrial fibrillation or flutter, can also be present [32](#page=32).
On physical examination, a soft systolic ejection murmur may be heard in the pulmonary area. A hallmark finding is a fixed, wide split S2 sound [32](#page=32).
#### 17.1.4 Diagnosis
The diagnostic evaluation for ASD typically includes transthoracic echocardiography (TEE) as the best imaging test. A chest X-ray (CXR) may reveal enlarged pulmonary arteries and increased pulmonary vascular markings. Electrocardiography (ECG) can show right axis deviation (RAD), right bundle branch block (RBBB), and evidence of atrial arrhythmias [32](#page=32).
#### 17.1.5 Complications
Potential complications of ASD include the development of pulmonary hypertension. If the shunt reverses due to pulmonary hypertension, Eisenmenger syndrome can occur, leading to cyanosis and clubbing. Right heart failure is another significant complication, as is the increased incidence of atrial arrhythmias, particularly atrial fibrillation. Paradoxical embolic strokes can also occur if a clot crosses from the venous to the arterial circulation [32](#page=32).
#### 17.1.6 Management
Management strategies for ASD depend on the size of the defect and the presence of symptoms. Small, asymptomatic defects may be managed with observation. Closure of the defect is typically recommended if the patient is symptomatic or if the ratio of pulmonary blood flow to systemic blood flow (Qp:Qs) is greater than or equal to 1.5:1 or 2:1 [32](#page=32).
### 17.2 Ventricular septal defect (VSD)
#### 17.2.1 Definition and types
A ventricular septal defect (VSD) is defined as a defect in the interventricular septum, creating a communication between the left ventricle (LV) and the right ventricle (RV). VSD is the most common congenital cardiac malformation [32](#page=32).
#### 17.2.2 Pathophysiology
The pathophysiology of VSD involves a left-to-right (L-R) shunt from the higher-pressure LV to the lower-pressure RV. This results in increased pulmonary blood flow. Large VSDs lead to LV volume overload, which can cause LV dilation and heart failure. Similar to ASD, prolonged increased pulmonary blood flow can lead to pulmonary hypertension and, eventually, Eisenmenger syndrome with a reversed R-L shunt and cyanosis [32](#page=32).
> **Example:** In a VSD, the left ventricle must pump extra blood through the defect into the right ventricle, increasing the workload on the LV and potentially leading to heart failure if the defect is large.
#### 17.2.3 Clinical features
The clinical presentation of VSD varies with the size of the defect. Small VSDs are often asymptomatic, and affected individuals typically have normal growth and development. In contrast, large VSDs can lead to failure to thrive (FTT), dyspnea, recurrent chest infections, and signs of congestive heart failure (CHF) [32](#page=32).
Physical examination may reveal a harsh holosystolic murmur accompanied by a thrill, typically heard at the left lower sternal border (fourth intercostal space). Interestingly, smaller holes can sometimes produce louder murmurs due to the high velocity of the blood jet. A right ventricular (RV) heave may be palpable, and a loud P2 component of the second heart sound can indicate the presence of pulmonary hypertension [32](#page=32).
#### 17.2.4 Diagnosis
Diagnostic methods for VSD include ECG, which may show biventricular hypertrophy in cases of large defects or high pulmonary vascular resistance (PVR). A CXR can demonstrate cardiomegaly and increased pulmonary vascular markings. Echocardiography is crucial for defining the size, location, and hemodynamic significance of the shunt [32](#page=32).
#### 17.2.5 Complications
Complications associated with VSD include infective endocarditis, as the turbulent blood flow can predispose to bacterial colonization. Progressive aortic regurgitation can occur, particularly with defects in the subaortic region. Heart failure is a significant risk for large VSDs, and the development of pulmonary hypertension with subsequent Eisenmenger syndrome is also a serious concern [32](#page=32).
#### 17.2.6 Management
Management of VSD typically involves observation for small, asymptomatic defects. Surgical closure is indicated if the Qp:Qs ratio is greater than 1.5:1 or 2:1, if the patient has symptoms, exhibits LV dysfunction, or has experienced infective endocarditis. The general approach is to close VSDs early, ideally before irreversible pulmonary hypertension develops [32](#page=32).
---
# Congenital heart defects: coarctation of the aorta and PDA
This section details two significant congenital heart defects: coarctation of the aorta, characterized by a narrowing of the aorta, and patent ductus arteriosus (PDA), a persistent connection between the aorta and pulmonary artery.
### 18.1 Coarctation of the aorta
Coarctation of the aorta is a congenital narrowing of the aorta, typically located near the origin of the left subclavian artery or the ligamentum arteriosum [33](#page=33).
#### 18.1.1 Hemodynamics
This narrowing leads to increased left ventricular (LV) afterload, potentially causing LV hypertrophy. Consequently, blood pressure is elevated proximal to the coarctation, affecting the head and arms, while pressure is low distal to the narrowing, affecting the abdomen and legs [33](#page=33).
> **Tip:** Think of coarctation as a "traffic jam" on the aorta just after the left subclavian artery, creating high pressure before it and low pressure after [33](#page=33).
#### 18.1.2 Clinical features
Clinical manifestations include hypertension in the upper extremities, weak or delayed femoral pulses (radio-femoral delay), and more developed upper body musculature compared to the lower body. Patients may also experience headaches, leg fatigue, cold feet, and claudication. A midsystolic murmur heard over the back is a common finding [33](#page=33).
#### 18.1.3 Diagnosis
The diagnostic approach includes CT angiography, which is the test of choice. Electrocardiography (ECG) may reveal LV hypertrophy. Chest X-ray (CXR) can show characteristic findings such as rib notching due to collateral intercostal arteries and a "Figure 3" sign of the aorta [33](#page=33).
#### 18.1.4 Complications
Potential complications of coarctation of the aorta are severe hypertension, cerebral aneurysm rupture leading to subarachnoid hemorrhage (SAH), infective endocarditis, and aortic dissection [33](#page=33).
#### 18.1.5 Management
Management involves surgical repair for decompression or balloon angioplasty and stenting in selected patients [33](#page=33).
### 18.2 Patent ductus arteriosus (PDA)
#### 18.2.1 Definition
Patent ductus arteriosus (PDA) is defined as a persistent communication between the aorta and the pulmonary artery after birth. In fetal circulation, the ductus arteriosus is a normal structure maintained by low oxygen levels and prostaglandin E2 [33](#page=33).
> **Tip:** In utero, the ductus arteriosus acts as a vital shortcut between the pulmonary artery and the aorta, bypassing the non-functional fetal lungs. After birth, it is supposed to close. When it fails to close, it's called a PDA [33](#page=33).
#### 18.2.2 Etiology and associations
PDA is associated with prematurity, congenital rubella infection, high altitude, and can occasionally be idiopathic [33](#page=33).
#### 18.2.3 Pathophysiology
After birth, systemic pressure typically exceeds pulmonary pressure. This pressure gradient drives a left-to-right shunt from the aorta to the pulmonary artery. This increased pulmonary blood flow can lead to pulmonary hypertension and volume overload of the left ventricle (LV), potentially causing LV dilation, hypertrophy, and heart failure (HF). If pulmonary hypertension is long-standing and pulmonary vascular resistance (PVR) increases significantly, the shunt can reverse to a right-to-left shunt, a condition known as Eisenmenger syndrome, leading to late cyanosis, particularly in the lower limbs [33](#page=33).
#### 18.2.4 Clinical features
Small PDAs may be asymptomatic. Larger PDAs can present with symptoms of heart failure, including dyspnea, failure to thrive (FTT), and recurrent infections. A characteristic continuous "machinery" murmur is typically heard at the left second intercostal space, accompanied by a loud P2. Patients may also exhibit a wide pulse pressure with bounding pulses. Differential cyanosis, where toes show bluer discoloration than fingers, can be observed due to the shunt dynamics [33](#page=33).
#### 18.2.5 Diagnosis
Diagnosis is aided by chest X-ray (CXR), which may show increased pulmonary markings, a dilated pulmonary artery, and cardiomegaly. Echocardiography is the test of choice, as it can visualize the PDA and detect turbulent blood flow across it [33](#page=33).
#### 18.2.6 Treatment
Treatment depends on the presence of pulmonary vascular disease [33](#page=33).
* **No pulmonary vascular disease:** Management involves surgical or device ligation of the PDA. In infants, indomethacin can be used to promote closure [33](#page=33).
* **Need for ductus patency (e.g., in Transposition of the Great Arteries - TGA):** Prostaglandin E1 infusion is used to maintain ductal patency [33](#page=33).
* **Severe pulmonary hypertension with a right-to-left shunt:** Closing the PDA is contraindicated in these cases [33](#page=33).
#### 18.2.7 Complications
Complications of PDA include heart failure, pulmonary hypertension leading to Eisenmenger syndrome, and infective endocarditis [33](#page=33).
---
# Tetralogy of Fallot (TOF)
Tetralogy of Fallot (TOF) is a complex cyanotic congenital heart disease characterized by four distinct cardiac lesions that lead to significant right-to-left shunting of deoxygenated blood [34](#page=34).
### 19.1 Core definition
Tetralogy of Fallot (TOF) is a cyanotic congenital heart disease defined by the presence of four key lesions [34](#page=34):
1. Ventricular septal defect (VSD) [34](#page=34).
2. Pulmonary stenosis or right ventricular (RV) outflow obstruction [34](#page=34).
3. Overriding aorta [34](#page=34).
4. Right ventricular hypertrophy (RVH) [34](#page=34).
### 19.2 Pathophysiology
The pathophysiology of TOF stems from the interplay of these four defects, leading to reduced pulmonary blood flow and systemic deoxygenation [34](#page=34).
* **Pulmonary stenosis:** This obstruction increases the pressure within the right ventricle (RV) [34](#page=34).
* **Right-to-left shunt:** Due to the increased RV pressure and the VSD, deoxygenated blood from the RV shunts across the VSD into the aorta (a right-to-left shunt) [34](#page=34).
* **Degree of cyanosis:** The severity of cyanosis is directly proportional to the degree of pulmonary stenosis. A more severe obstruction leads to more deoxygenated blood bypassing the lungs and entering systemic circulation [34](#page=34).
* **Tet spells:** During periods of exertion, crying, or increased demand, systemic vascular resistance (SVR) may increase, and oxygen demand rises. This leads to a further increase in the right-to-left shunt, resulting in sudden, severe cyanosis and dyspnea known as Tet spells [34](#page=34).
* **Effect of squatting:** Conversely, squatting or assuming a knee-chest position can alleviate cyanosis. This maneuver increases SVR, which pushes more blood towards the lungs, thereby improving oxygenation [34](#page=34).
> **Tip:** The severity of pulmonary stenosis is a critical determinant of symptom severity in TOF.
> **Example:** A child with mild pulmonary stenosis might have minimal cyanosis, while a child with severe stenosis will likely present with significant cyanosis and frequent Tet spells.
### 19.3 Clinical features
Infants and children with TOF present with a range of clinical signs and symptoms reflecting the degree of shunting and cyanosis [34](#page=34).
* **Cyanosis:** Typically presents in infancy or early childhood [34](#page=34).
* **Tet spells:** Characterized by sudden episodes of severe cyanosis, dyspnea, and irritability [34](#page=34).
* **Squatting:** Children often assume a squatting position after exertion to improve their oxygenation [34](#page=34).
* **Murmur:** A systolic crescendo-decrescendo murmur is typically heard at the left upper sternal border, in the pulmonic area [34](#page=34).
* **Chronic signs:** Clubbing of the fingers and toes and failure to thrive can be observed in cases of chronic hypoxemia [34](#page=34).
### 19.4 Diagnosis
Diagnosis of TOF relies on a combination of clinical assessment and diagnostic imaging [34](#page=34).
* **Echocardiography:** This is the test of choice for diagnosing TOF as it can clearly define all four cardiac lesions [34](#page=34).
* **Electrocardiogram (ECG):** May show evidence of right atrial enlargement and RVH [34](#page=34).
* **Chest X-ray (CXR):** Often reveals a characteristic "boot-shaped heart" (coeur en botte) due to RV hypertrophy and a narrow pulmonary artery segment [34](#page=34).
* **Cardiac catheterization:** May be used for detailed anatomical assessment when further clarification is needed [34](#page=34).
### 19.5 Treatment
The management of TOF involves both immediate interventions for spells and definitive surgical correction [34](#page=34).
* **Definitive treatment:** Surgical repair is the definitive treatment, typically performed within the first year of life. This involves closing the VSD and relieving the RV outflow obstruction [34](#page=34).
* **Management of Tet spells:** During Tet spells, immediate interventions include positioning the child knee-chest or squatting, administering oxygen, morphine for vasodilation and to reduce respiratory drive, and beta-blockers to reduce RV outflow obstruction [34](#page=34).
* **Late complications:** Patients may experience late complications such as arrhythmias, pulmonary regurgitation, residual RV obstruction, and heart failure [34](#page=34).
---
## Common mistakes to avoid
- Review all topics thoroughly before exams
- Pay attention to formulas and key definitions
- Practice with examples provided in each section
- Don't memorize without understanding the underlying concepts
Glossary
| Term | Definition |
|------|------------|
| Stable Angina | Chest pain or discomfort that occurs when the heart muscle does not get enough oxygen-rich blood. It is typically triggered by physical exertion or emotional stress and is relieved by rest or nitroglycerin. |
| Coronary Artery Disease (CAD) | A condition in which the major blood vessels that supply the heart, known as the coronary arteries, become damaged or diseased, often due to the buildup of fatty deposits called plaque. |
| Ischemic Heart Disease | A broad term for heart problems caused by narrowed heart arteries that reduce blood flow to the heart muscle. Stable angina and myocardial infarction are types of ischemic heart disease. |
| Atherosclerotic Lesion | A buildup of plaque, consisting of cholesterol, fat, and other substances, within the walls of arteries, leading to their narrowing or hardening. |
| Myocardial Infarction (MI) | Commonly known as a heart attack, this occurs when blood flow to a part of the heart muscle is severely reduced or blocked, causing damage or death to that portion of the heart muscle. |
| Unstable Angina | A type of acute coronary syndrome that occurs when plaque in the coronary arteries ruptures or erodes, leading to a blood clot that partially or completely blocks blood flow. It is characterized by new-onset, worsening, or rest angina and is a medical emergency. |
| Acute Coronary Syndrome (ACS) | A term used to describe a range of conditions associated with sudden, reduced blood flow to the heart, including unstable angina, non-ST-elevation myocardial infarction (NSTEMI), and ST-elevation myocardial infarction (STEMI). |
| NSTEMI (Non-ST-Segment Elevation Myocardial Infarction) | A type of heart attack that occurs when blood flow to the heart muscle is reduced or blocked, but without the characteristic ST-segment elevation on an electrocardiogram seen in STEMI. Diagnosis is confirmed by elevated cardiac enzymes. |
| STEMI (ST-Segment Elevation Myocardial Infarction) | A severe type of heart attack characterized by a complete blockage of a coronary artery, resulting in ST-segment elevation on an electrocardiogram, indicating significant myocardial injury. |
| Ventricular Fibrillation (VF) | A life-threatening heart rhythm disorder in which the ventricles of the heart quiver chaotically instead of pumping blood effectively, leading to cardiac arrest. |
| Electrocardiogram (ECG) | A diagnostic test that records the electrical activity of the heart, used to detect heart rhythm abnormalities, ischemia, and myocardial infarction. |
| Troponin | A protein released into the bloodstream when the heart muscle is damaged, making it a highly sensitive and specific marker for myocardial infarction. |
| CK-MB (Creatine Kinase-Myocardial Band) | An enzyme released into the bloodstream when heart muscle is damaged. It was a traditional marker for myocardial infarction, though troponin is now preferred for its higher sensitivity and specificity. |
| Cardiac Catheterization | An invasive diagnostic procedure where a thin, flexible tube (catheter) is inserted into a blood vessel and guided to the heart to assess coronary arteries, heart chambers, and valves. |
| Percutaneous Coronary Intervention (PCI) | A non-surgical procedure used to open narrowed or blocked coronary arteries, typically involving angioplasty to inflate a balloon and often placing a stent to keep the artery open. |
| Coronary Artery Bypass Grafting (CABG) | A surgical procedure to improve blood flow to the heart by creating new pathways around blocked coronary arteries, using grafts from other parts of the body. |
| Heart Failure (HF) | A chronic condition in which the heart muscle cannot pump blood effectively enough to meet the body's needs, leading to symptoms like shortness of breath, fatigue, and fluid retention. |
| HFrEF (Heart Failure with Reduced Ejection Fraction) | A type of heart failure where the left ventricle's ability to contract (eject blood) is impaired, resulting in an ejection fraction below 40%. Also known as systolic heart failure. |
| HFpEF (Heart Failure with Preserved Ejection Fraction) | A type of heart failure where the left ventricle's ability to relax and fill with blood during diastole is impaired, despite a normal or near-normal ejection fraction. Also known as diastolic heart failure. |
| Ejection Fraction (EF) | The percentage of blood pumped out of the left ventricle with each contraction. A normal EF is typically above 50-55%. |
| BNP (B-type Natriuretic Peptide) | A hormone released by the ventricles in response to increased stretching or pressure, elevated in heart failure and used to help diagnose and assess its severity. |
| NT-proBNP (N-terminal pro-B-type Natriuretic Peptide) | An inactive fragment of the precursor to BNP, also elevated in heart failure and used for diagnosis and prognosis. |
| Pericarditis | Inflammation of the pericardium, the sac surrounding the heart, which can cause chest pain, fever, and a pericardial friction rub. |
| Cardiac Tamponade | A medical emergency where excess fluid accumulates in the pericardial sac, compressing the heart and impairing its ability to pump effectively. |
| Constrictive Pericarditis | A chronic condition where the pericardium becomes thickened and fibrotic, restricting the heart's ability to fill properly during diastole, leading to signs of heart failure. |
| Pericardial Effusion | An abnormal accumulation of fluid in the pericardial space surrounding the heart. |
| Aortic Stenosis (AS) | A condition where the aortic valve narrows, restricting blood flow from the left ventricle to the aorta, leading to increased workload on the left ventricle. |
| Mitral Stenosis (MS) | A condition where the mitral valve narrows, restricting blood flow from the left atrium to the left ventricle, leading to increased pressure in the left atrium and lungs. |
| Aortic Regurgitation (AR) | A condition where the aortic valve does not close properly, allowing blood to leak back from the aorta into the left ventricle during diastole. |
| Mitral Regurgitation (MR) | A condition where the mitral valve does not close properly, allowing blood to leak back from the left ventricle into the left atrium during systole. |
| Tricuspid Regurgitation (TR) | A condition where the tricuspid valve does not close properly, allowing blood to leak back from the right ventricle into the right atrium during systole. |
| Mitral Valve Prolapse (MVP) | A condition where the leaflets of the mitral valve bulge or prolapse into the left atrium during systole, sometimes causing a characteristic click and murmur, and occasionally leading to mitral regurgitation. |
| Rheumatic Heart Disease (RHD) | Damage to heart valves resulting from rheumatic fever, a complication of untreated streptococcal pharyngitis, most commonly affecting the mitral valve. |
| Infective Endocarditis (IE) | An infection of the inner lining of the heart chambers and valves, usually caused by bacteria, which can lead to severe valve damage and systemic complications. |
| Duke Criteria | A set of diagnostic criteria used to diagnose infective endocarditis, involving clinical findings, blood cultures, and echocardiographic evidence. |
| Aortic Dissection | A serious condition in which a tear occurs in the inner layer of the aorta, allowing blood to flow between the layers of the aortic wall, potentially leading to rupture or obstruction of blood flow to organs. |
| Abdominal Aortic Aneurysm (AAA) | A localized widening or bulging of the abdominal aorta, typically caused by atherosclerosis, which can rupture and be life-threatening. |
| Hypertensive Emergency | A severe elevation in blood pressure (BP ≥180/120 mmHg) accompanied by acute damage to one or more end-organs, requiring immediate reduction of blood pressure to prevent further damage. |
| Peripheral Arterial Disease (PAD) | A condition characterized by narrowing or blockage of arteries in the limbs, most commonly the legs, due to atherosclerosis, leading to reduced blood flow and symptoms like claudication. |
| Intermittent Claudication | Pain or cramping in the legs or buttocks that occurs during physical activity, such as walking, and is relieved by rest, caused by insufficient blood flow to the muscles due to PAD. |
| Deep Venous Thrombosis (DVT) | The formation of a blood clot in a deep vein, most commonly in the legs, which can lead to swelling, pain, and the risk of pulmonary embolism. |
| Virchow Triad | The three primary factors believed to contribute to the formation of venous thrombosis: venous stasis, intimal injury, and hypercoagulability. |
| Pulmonary Embolism (PE) | A condition where a blood clot, usually originating from a deep vein thrombosis (DVT), travels to the lungs and blocks one or more pulmonary arteries, causing breathing difficulties and potentially being fatal. |
| Chronic Venous Insufficiency (CVI) | A condition characterized by impaired venous return from the legs to the heart, often due to damaged valves in the veins, leading to symptoms like edema, skin changes, and venous ulcers. |
| Superficial Thrombophlebitis | Inflammation and clotting in a superficial vein, often presenting as a tender, red, cord-like mass along the course of the vein, usually associated with varicose veins or IV cannulation. |
| Atrial Septal Defect (ASD) | A congenital heart defect characterized by an abnormal opening between the left and right atria, allowing blood to shunt from the left atrium to the right atrium. |
| Ventricular Septal Defect (VSD) | A congenital heart defect characterized by an abnormal opening between the left and right ventricles, allowing blood to shunt from the left ventricle to the right ventricle. |
| Coarctation of the Aorta | A congenital narrowing of the aorta, typically near the left subclavian artery, leading to high blood pressure in the upper extremities and low blood pressure in the lower extremities. |
| Patent Ductus Arteriosus (PDA) | A congenital heart defect where the ductus arteriosus, a blood vessel that connects the aorta and pulmonary artery in fetal circulation, fails to close after birth, allowing blood to shunt from the aorta to the pulmonary artery. |
| Tetralogy of Fallot (TOF) | A complex cyanotic congenital heart disease characterized by four specific defects: a ventricular septal defect (VSD), pulmonary stenosis, overriding aorta, and right ventricular hypertrophy (RVH). |
| Hypokinesia | Reduced or weakened muscle movement. In cardiology, it refers to impaired movement of a section of the heart wall. |
| Hypertrophy | An increase in the size of an organ or tissue due to an increase in the size of its cells. In the heart, it can refer to thickening of the muscle walls. |
| Diastolic Dysfunction | Impaired relaxation and filling of the ventricles during diastole, leading to increased filling pressures and often heart failure. |
| Systolic Anterior Motion (SAM) | A phenomenon observed in hypertrophic cardiomyopathy where the anterior mitral leaflet moves towards the septum during systole, contributing to left ventricular outflow tract obstruction. |
| Left Ventricular Outflow Tract (LVOT) Obstruction | A narrowing or blockage in the path of blood leaving the left ventricle, commonly seen in hypertrophic cardiomyopathy, leading to reduced cardiac output and symptoms. |
| Pericardial Sac | The double-layered membrane that surrounds the heart, consisting of the visceral pericardium (adhering to the heart) and the parietal pericardium (outer layer), with a small amount of fluid in between. |
| Cardiac Tamponade | A medical emergency where excess fluid accumulates in the pericardial sac, compressing the heart and impairing its ability to fill and pump blood effectively. |
| Myocarditis | Inflammation of the heart muscle (myocardium), often caused by viral infections, which can lead to chest pain, heart failure, arrhythmias, and sudden death. |
| Restrictive Cardiomyopathy (RCM) | A condition characterized by stiffening of the ventricles, impairing their ability to relax and fill with blood, while systolic function may be preserved. It is often caused by infiltrative diseases like amyloidosis. |
| Hypertrophic Cardiomyopathy (HCM) | A genetic disorder characterized by abnormal thickening of the heart muscle, particularly the left ventricle, leading to diastolic dysfunction and potential outflow tract obstruction. |
| Aortic Regurgitation | A condition where the aortic valve does not close properly, allowing blood to leak back from the aorta into the left ventricle during diastole. |
| Mitral Regurgitation | A condition where the mitral valve does not close properly, allowing blood to leak back from the left ventricle into the left atrium during systole. |
| Tricuspid Regurgitation | A condition where the tricuspid valve does not close properly, allowing blood to leak back from the right ventricle into the right atrium during systole. |
| Mitral Valve Prolapse (MVP) | A condition where the leaflets of the mitral valve bulge or prolapse into the left atrium during systole. |
| Rheumatic Heart Disease | Damage to heart valves resulting from rheumatic fever, a complication of untreated streptococcal pharyngitis, most commonly affecting the mitral valve. |
| Infective Endocarditis | An infection of the inner lining of the heart chambers and valves, usually caused by bacteria, which can lead to severe valve damage and systemic complications. |
| Duke Criteria | A set of diagnostic criteria used to diagnose infective endocarditis, involving clinical findings, blood cultures, and echocardiographic evidence. |
| Aortic Dissection | A serious condition in which a tear occurs in the inner layer of the aorta, allowing blood to flow between the layers of the aortic wall, potentially leading to rupture or obstruction of blood flow to organs. |
| Abdominal Aortic Aneurysm (AAA) | A localized widening or bulging of the abdominal aorta, typically caused by atherosclerosis, which can rupture and be life-threatening. |
| Hypertensive Emergency | A severe elevation in blood pressure (BP ≥180 systolic and/or ≥120 diastolic) accompanied by acute damage to one or more end-organs, requiring immediate reduction of blood pressure to prevent further damage. |
| Cholesterol Embolization Syndrome | A systemic condition caused by the release of cholesterol crystals from atherosclerotic plaques, typically triggered by vascular procedures, affecting multiple organs including the kidneys, skin, and gastrointestinal tract. |
| Mycotic Aneurysm | An aneurysm caused by an infection of the arterial wall, often due to a bacterial embolus, which can lead to arterial wall weakening, rupture, and potentially systemic spread of infection. |
| Luetic Heart | A manifestation of tertiary syphilis affecting the cardiovascular system, primarily causing aortitis, leading to aortic valve regurgitation and aneurysms of the aorta. |
| Peripheral Arterial Disease (PAD) | A condition characterized by narrowing or blockage of arteries in the limbs, most commonly the legs, due to atherosclerosis, leading to reduced blood flow and symptoms like claudication. |
| Acute Arterial Occlusion (AAO) | The sudden blockage of an artery, most commonly caused by an embolus originating from the heart, leading to acute ischemia and potential tissue death in the affected limb. |
| Deep Venous Thrombosis (DVT) | The formation of a blood clot in a deep vein, most commonly in the legs, which can lead to swelling, pain, and the risk of pulmonary embolism. |
| Virchow Triad | The three primary factors believed to contribute to the formation of venous thrombosis: venous stasis, intimal injury, and hypercoagulability. |
| Pulmonary Embolism (PE) | A condition where a blood clot, usually originating from a deep vein thrombosis (DVT), travels to the lungs and blocks one or more pulmonary arteries, causing breathing difficulties and potentially being fatal. |
| Chronic Venous Insufficiency (CVI) | A condition characterized by impaired venous return from the legs to the heart, often due to damaged valves in the veins, leading to symptoms like edema, skin changes, and venous ulcers. |
| Superficial Thrombophlebitis | Inflammation and clotting in a superficial vein, often presenting as a tender, red, cord-like mass along the course of the vein, usually associated with varicose veins or IV cannulation. |
| Atrial Septal Defect (ASD) | A congenital heart defect characterized by an abnormal opening between the left and right atria, allowing blood to shunt from the left atrium to the right atrium. |
| Ventricular Septal Defect (VSD) | A congenital heart defect characterized by an abnormal opening between the left and right ventricles, allowing blood to shunt from the left ventricle to the right ventricle. |
| Coarctation of the Aorta | A congenital narrowing of the aorta, typically near the left subclavian artery, leading to high blood pressure in the upper extremities and low blood pressure in the lower extremities. |
| Patent Ductus Arteriosus (PDA) | A congenital heart defect where the ductus arteriosus, a blood vessel that connects the aorta and pulmonary artery in fetal circulation, fails to close after birth, allowing blood to shunt from the aorta to the pulmonary artery. |
| Tetralogy of Fallot (TOF) | A complex cyanotic congenital heart disease characterized by four specific defects: a ventricular septal defect (VSD), pulmonary stenosis, overriding aorta, and right ventricular hypertrophy (RVH). |
| Tricuspid Regurgitation | A condition where the tricuspid valve does not close properly, allowing blood to leak back from the right ventricle into the right atrium during systole. |
| Mitral Valve Prolapse (MVP) | A condition where the leaflets of the mitral valve bulge or prolapse into the left atrium during systole. |
| Aortic Stenosis | A condition where the aortic valve narrows, restricting blood flow from the left ventricle to the aorta, leading to increased workload on the left ventricle. |
| Mitral Stenosis | A condition where the mitral valve narrows, restricting blood flow from the left atrium to the left ventricle, leading to increased pressure in the left atrium and lungs. |
| Angina | Chest pain or discomfort due to reduced blood flow to the heart muscle, typically caused by coronary artery disease. |
| Electrocardiogram (ECG) | A diagnostic test that records the electrical activity of the heart, used to detect heart rhythm abnormalities, ischemia, and myocardial infarction. |
| Echocardiogram | An ultrasound of the heart that provides images of its structure and function, used to assess valves, chambers, and contractility. |
| Cardiac Catheterization | An invasive diagnostic procedure where a thin, flexible tube (catheter) is inserted into a blood vessel and guided to the heart to assess coronary arteries, heart chambers, and valves. |
| Cardiac Tamponade | A medical emergency where excess fluid accumulates in the pericardial sac, compressing the heart and impairing its ability to fill and pump blood effectively. |
| Congestive Heart Failure (CHF) | A chronic condition in which the heart muscle cannot pump blood effectively enough to meet the body's needs, leading to symptoms like shortness of breath, fatigue, and fluid retention. |
| Diastolic dysfunction | Impaired relaxation and filling of the ventricles during diastole, leading to increased filling pressures and often heart failure. |
| Systolic dysfunction | Impaired contraction and ejection of blood from the ventricles, leading to reduced cardiac output and often heart failure. |
| Ejection Fraction (EF) | The percentage of blood pumped out of the left ventricle with each contraction. A normal EF is typically above 50-55%. |
| BNP (B-type Natriuretic Peptide) | A hormone released by the ventricles in response to increased stretching or pressure, elevated in heart failure and used to help diagnose and assess its severity. |
| Ventricular Septal Defect (VSD) | A congenital heart defect characterized by an abnormal opening between the left and right ventricles, allowing blood to shunt from the left ventricle to the right ventricle. |
| Atrial Septal Defect (ASD) | A congenital heart defect characterized by an abnormal opening between the left and right atria, allowing blood to shunt from the left atrium to the right atrium. |
| Tetralogy of Fallot (TOF) | A complex cyanotic congenital heart disease characterized by four specific defects: a ventricular septal defect (VSD), pulmonary stenosis, overriding aorta, and right ventricular hypertrophy (RVH). |
| Pulmonary Stenosis | Narrowing of the pulmonary valve, restricting blood flow from the right ventricle to the pulmonary artery, often associated with congenital heart defects. |
| Right Ventricular Hypertrophy (RVH) | An increase in the size of the right ventricle, often due to increased workload from pulmonary hypertension or a right-to-left shunt. |
| Eisenmenger Syndrome | A complication of large congenital heart defects with shunts that leads to pulmonary hypertension, reversal of the shunt (right-to-left), and cyanosis. |
| Coarctation of the Aorta | A congenital narrowing of the aorta, typically near the left subclavian artery, leading to high blood pressure in the upper extremities and low blood pressure in the lower extremities. |
| Patent Ductus Arteriosus (PDA) | A congenital heart defect where the ductus arteriosus, a blood vessel that connects the aorta and pulmonary artery in fetal circulation, fails to close after birth, allowing blood to shunt from the aorta to the pulmonary artery. |