What heart sound is associated with the opening of a defective semilunar valve?

The opening snap is a characteristic heart sound that can be associated with conditions such as mitral stenosis; however, when considering semilunar valves specifically, it can indicate an abnormal opening due to a defect in the valve. In a typical situation, when a valve opens smoothly, there is a subtle sound; but if the valve is defective or abnormal, there may be a more pronounced sound associated with the sudden opening. This is due to increased resistance or abnormal characteristics of the valve tissue.

While the split S2 occurs due to the asynchronous closure of the aortic and pulmonary valves during respiration, it does not indicate a defect in the valve itself. S3 and S4 heart sounds are associated with different phases of cardiac function and do not relate directly to the opening of semilunar valves. The opening snap, on the other hand, signifies a specific abnormality during the opening phase of a valve and can be linked to the pathophysiological changes seen in valve defects.