What condition is suggested by a paradoxically split S2?

A paradoxically split S2 occurs when the second heart sound (S2) is split into two components that are heard closely together during expiration, instead of the usual splitting during inspiration. This phenomenon is typically associated with conditions that affect the timing of the closure of the aortic and pulmonic valves.

In the case of aortic stenosis, the left ventricle has difficulty ejecting blood into the aorta due to the narrowed valve. This prolonged ejection time causes the closure of the aortic valve to be delayed relative to the pulmonary valve closure, leading to a paradoxical split S2. The delay in aortic valve closure overrides the normal physiological splitting that occurs with respiration, resulting in the abnormal sound heard during auscultation.

This is distinct from other conditions; for instance, aortic regurgitation and mitral valve stenosis typically do not produce a paradoxical split S2, and pulmonary embolism may be associated with changes to the heart sounds, but not specifically with this type of splitting. Understanding the mechanics of valve closure and their relations can help in recognizing how aortic stenosis specifically contributes to a paradoxical split S2.