What heart sound is often associated with heart failure?

The S3 gallop is often associated with heart failure, particularly in cases of volume overload or decreased ventricular compliance. When the heart fails to pump effectively, as seen in heart failure, there can be an increase in blood volume within the left ventricle during diastole. This results in a third heart sound (S3) due to the rapid filling of the ventricle. The sound is produced when blood from the atria enters an already filled ventricle, and it is typically best heard in the left lateral position using a stethoscope. In adults, the presence of an S3 is strongly indicative of heart failure and is often described as a low-pitched, galloping sound.

S1 and S2 are heart sounds that reflect the closure of heart valves during the cardiac cycle; S1 marks the onset of ventricular systole, while S2 marks the end of systole. Though essential for assessing cardiac function, they are not specifically associated with heart failure. A friction rub, on the other hand, is typically related to pericarditis and not heart failure, indicating inflammation of the pericardium, the fibrous sac surrounding the heart. Therefore, the S3 gallop sound is the most relevant indicator