2.2 Cardiovascular II: Arrhythmias, Valvular & Other

Rhythm, Structure, and the Rest of the Cardiovascular Blueprint

The second cardiovascular block within the 12% PANRE category covers arrhythmias, valvular heart disease, infective endocarditis and pericarditis, the cardiomyopathies, and the electrocardiogram (ECG) reading skills that tie them together. The recurring exam pattern: identify the rhythm or structural lesion, decide whether the patient is stable, and select the next best step.

Atrial Fibrillation and Other Arrhythmias

Atrial fibrillation (AF) is an irregularly irregular rhythm without discrete P waves and is the most commonly tested arrhythmia. Management has three pillars: control the rate, consider rhythm control, and address stroke prevention. Anticoagulation decisions are guided by a validated clinical stroke-risk score rather than by symptom burden alone, balanced against bleeding risk.

The first triage question for any tachyarrhythmia is hemodynamic stability. An unstable patient (hypotension, altered mentation, ischemic chest pain, or acute heart failure) with a tachyarrhythmia receives synchronized cardioversion; pulseless ventricular tachycardia (VT) or ventricular fibrillation (VF) receives immediate defibrillation and resuscitation.

Other high-yield rhythms include supraventricular tachycardia (SVT) (regular narrow-complex tachycardia treated with vagal maneuvers then nodal-blocking therapy when stable), bradyarrhythmias and AV block (symptomatic high-grade block may need pacing), and wide-complex tachycardia, which is treated as ventricular tachycardia until proven otherwise.

Valvular Heart Disease

Murmurs localize the lesion. Aortic stenosis (AS) produces a crescendo-decrescendo systolic ejection murmur at the right upper sternal border with the classic triad of exertional dyspnea, angina, and syncope; severe symptomatic AS is referred for valve replacement (surgical or transcatheter as appropriate).

Mitral regurgitation (MR) produces a holosystolic apical murmur radiating to the axilla and can cause volume overload and atrial fibrillation. Mitral stenosis produces a diastolic rumble and is associated with rheumatic disease and AF. Aortic regurgitation produces an early diastolic decrescendo murmur with a wide pulse pressure. Echocardiography quantifies severity and guides timing of referral.

Infective Endocarditis and Pericarditis

Infective endocarditis (IE) should be suspected with persistent fever plus a new or changing regurgitant murmur, embolic phenomena, or risk factors such as injection drug use, prosthetic valves, or recent bacteremia. Workup centers on blood cultures and echocardiography; management is prolonged targeted antimicrobial therapy with surgical evaluation for complications such as heart failure, abscess, or large mobile vegetations.

Acute pericarditis presents with sharp pleuritic chest pain that improves leaning forward and worsens supine, often with a pericardial friction rub and diffuse ECG changes. Management commonly uses anti-inflammatory therapy with adjunctive colchicine, while watching for a pericardial effusion progressing to cardiac tamponade (hypotension, distended neck veins, muffled heart sounds, and pulsus paradoxus), which is a drainage emergency.

Cardiomyopathies

Dilated cardiomyopathy causes a dilated, poorly contractile ventricle and presents as systolic heart failure; treat the underlying cause and apply HFrEF guideline-directed therapy. Hypertrophic cardiomyopathy (HCM) can cause exertional syncope, a dynamic outflow murmur that increases with reduced preload, and is an important cause of sudden cardiac death in young patients; counsel on activity, screen family members, and risk-stratify for an implantable defibrillator. Restrictive cardiomyopathy causes impaired filling with prominent right-sided congestion and is managed by treating the underlying infiltrative or fibrotic process.

ECG Essentials

Read every ECG the same way: rate, rhythm, axis, intervals (PR, QRS, QT), and ischemic changes. Anchor recognition of emergent patterns: ST-segment elevation in contiguous leads suggests STEMI; complete (third-degree) AV block shows P waves and QRS complexes marching independently; a regular wide-complex tachycardia is treated as ventricular tachycardia until proven otherwise; and a markedly prolonged QT interval flags risk for torsades de pointes, prompting review of offending drugs and electrolytes.