What is a classic heart sound associated with dilated cardiomyopathy?

The classic heart sound associated with dilated cardiomyopathy is the third heart sound, or S3. This sound is primarily indicative of volume overload in the ventricles and is often associated with conditions involving heart failure, including dilated cardiomyopathy.

In dilated cardiomyopathy, the heart's ability to pump blood is compromised due to the enlargement of the heart chambers, particularly the left ventricle. As a result, there is an increase in the volume of blood that fills the heart during diastole. The S3 sound occurs when blood rushes into a dilated ventricle and may be heard shortly after S2, which represents the closure of the aortic and pulmonary valves. The presence of an S3 heart sound is considered a hallmark of heart failure and suggests increased filling pressures.

To clarify the other options: S1 typically represents the closure of the mitral and tricuspid valves at the beginning of ventricular contraction, while S2 indicates the closure of the aortic and pulmonary valves at the end of ventricular systole. S4 is associated with conditions that involve a stiff or hypertrophied left ventricle, which is more common in hypertensive heart disease or aortic stenosis, making it less