Which heart sound is least likely to be heard with elevated CVP from fluid overload?

Which heart sound is least likely to be heard with elevated CVP from fluid overload?

• A. S1
• B. S2
• C. S3
• D. S4

Answer: (D)

Elevated CVP from fluid overload mainly reflects increased preload and venous congestion, so the heart often shows signs of rapid ventricular filling in early diastole. That produces S3, a soft gallop heard with the ventricle accepting a large volume and relaxed enough to fill quickly. S1 and S2 are the standard valve-closure sounds and can be heard across many states, but they don’t specifically indicate volume overload. S4, on the other hand, arises from atrial contraction against a stiff, noncompliant ventricle and is more typical of long-standing hypertension or diastolic dysfunction. In acute fluid overload, the ventricle is usually not stiff in this way, making S4 the least likely sound to be heard.