What heart sound is typically associated with heart failure and can indicate volume overload?

The S3 heart sound, also known as a "ventricular gallop," is typically associated with heart failure and can indicate volume overload in the ventricles. This sound occurs early in diastole when the blood rushes into the ventricles, which is especially pronounced in cases where there is an increase in ventricular filling pressure, commonly seen in heart failure.

In heart failure, particularly with preserved or reduced ejection fraction, the ventricles may become stiff or unable to handle the volume of blood efficiently, leading to an audible S3 sound. This sound suggests that the heart is struggling to manage increased blood volume, resulting in the abnormal rapid filling of the ventricles.

In contrast, S1 represents the closure of the atrioventricular valves and occurs at the beginning of ventricular contraction, while S2 corresponds to the closure of the semilunar valves at the end of ventricular contraction. The S4 sound, or "atrial gallop," occurs due to increased resistance to filling the ventricles, which is often associated with conditions like hypertensive heart disease or left ventricular hypertrophy and typically indicates a stiff ventricle rather than volume overload. Thus, S3 is the heart sound most distinctly linked to heart failure and volume overload.