S3 heart sounds are most commonly associated with which condition?

• A. Coronary artery disease
• B. Congestive heart failure
• C. Hyperthyroidism
• D. Pulmonary embolism

Answer: (C)

S3 is a ventricular gallop created by rapid early diastolic filling of a dilated ventricle when filling pressures are high. It most strongly points to congestive heart failure, where the ventricle is volume overloaded and accepts blood quickly after S2, producing that low-pitched sound heard best at the apex with the patient in the left lateral decubitus position using the bell.

Context helps: in younger people or in high‑output states (like pregnancy or anemia), an S3 can be present and not signify pathology, but in adults it usually indicates elevated left-sided filling pressures and heart failure. S4, by contrast, reflects a stiff ventricle from long-standing hypertension or hypertrophy and is heard before S1.