Overview
Clinical Meaning
Heart failure diagnosis requires integration of clinical symptoms, physical examination, natriuretic peptides, and echocardiographic assessment.
Heart failure diagnosis requires integration of clinical symptoms, physical examination, natriuretic peptides, and echocardiographic assessment. The Framingham criteria provide a clinical framework: diagnosis requires 2 major criteria OR 1 major + 2 minor criteria. Major criteria include paroxysmal nocturnal dyspnea, neck vein distension, rales, cardiomegaly on CXR, acute pulmonary edema, S3 gallop, increased CVP >16 cm H₂O, and hepatojugular reflux. Minor criteria include bilateral ankle edema, nocturnal cough, dyspnea on ordinary exertion, hepatomegaly, pleural effusion, decreased vital capacity by one-third, and tachycardia >120 bpm. BNP and NT-proBNP are released from ventricular myocytes in response to increased wall stress (volume/pressure overload). BNP <100 pg/mL or NT-proBNP <300 pg/mL essentially rules out acute HF (high negative predictive value). BNP >400 pg/mL or NT-proBNP >900 pg/mL (age-stratified) strongly supports HF diagnosis. The gray zone (BNP 100-400) requires clinical correlation. False elevations occur with renal failure, atrial fibrillation, pulmonary embolism, and sepsis. BNP is falsely LOW with obesity (adipocytes express natriuretic peptide clearance receptors). Echocardiography is the cornerstone: LVEF classifies HF into HFrEF (≤40%), HFmrEF (41-49%), and HFpEF (≥50%). Additional echo parameters include diastolic...