right-sided heart failure

Pathophysiology: The right ventricle fails to generate adequate output against pulmonary vascular resistance or fails due to intrinsic myocardial dysfunction, leading to increased right-sided filling pressures and backward transmission of pressure into the systemic venous system. This causes fluid accumulation in peripheral tissues and organs (liver, GI tract, lower extremities) rather than the lungs (which is characteristic of left-sided failure with pulmonary edema).

Etiologies: (1) Left-sided heart failure (most common cause - increased pulmonary venous pressure back-transmits to pulmonary arteries, increasing RV afterload); (2) Cor pulmonale - RV failure due to primary lung disease (COPD, pulmonary fibrosis, pulmonary embolism) causing pulmonary hypertension; (3) Right ventricular myocardial infarction (inferior MI with RV involvement); (4) Valvular disease (tricuspid or pulmonic stenosis/regurgitation); (5) Congenital heart disease with left-to-right shunts; (6) Arrhythmogenic right ventricular cardiomyopathy.

Clinical manifestations: Jugular venous distension (JVD), hepatomegaly ("nutmeg liver" on histology if chronic, can progress to cardiac cirrhosis), hepatojugular reflux, peripheral pitting edema (dependent, worse with standing), ascites, and in severe cases, anasarca. Patients may also have parasternal heave (RV hypertrophy), a right-sided S3 or S4, and signs of the underlying cause (e.g., loud P2 in pulmonary hypertension).

Diagnostic workup: Echocardiography shows RV dilation/dysfunction, elevated RV systolic pressure (estimate of pulmonary artery pressure), and evaluates for causes of pulmonary hypertension. BNP/NT-proBNP is elevated. ECG may show right axis deviation, right atrial enlargement (P pulmonale), or RVH. Chest X-ray may show cardiomegaly and pulmonary findings related to underlying lung disease.

Management: Treat underlying cause (e.g., diuretics for volume overload, treat left heart failure, manage pulmonary hypertension with vasodilators in select cases, oxygen for COPD-related cor pulmonale). Diuretics (loop diuretics) are mainstay for symptomatic relief of congestion. Avoid excessive preload reduction as RV is preload-dependent, especially in RV infarction where IV fluids may be needed instead of diuretics.

High-yield board points: Differentiate right heart failure signs (peripheral edema, JVD, hepatomegaly, ascites) from left heart failure signs (pulmonary edema, dyspnea, orthopnea, PND). Remember RV infarction classically presents with hypotension, JVD, and clear lung fields - treat with fluids, not diuretics/nitrates (which can precipitate cardiogenic shock by reducing preload).