Pathological S2 is commonly seen in which conditions?

Pathological S2 is commonly seen in which conditions?

• A. Right bundle branch block and pulmonary stenosis
• B. Aortic stenosis
• C. Mitral regurgitation
• D. Hypertrophic cardiomyopathy

Answer: (A)

Pathological S2 reflects an abnormal second heart sound, most often due to delayed closure of the pulmonic valve (P2). When conduction to the right ventricle is slowed, as in a right bundle branch block, the pulmonic valve closes later, widening the interval between A2 and P2. Pulmonary stenosis also delays P2 directly by obstructing outflow. Together, these conditions commonly produce a clearly widened S2, heard as a pathological splitting at the left upper sternal border. The other options don’t fit this pattern as neatly. Aortic stenosis mainly affects the aortic component (A2), often softening or delaying it rather than creating a wide, abnormal split. Mitral regurgitation and hypertrophic cardiomyopathy are not characteristically defined by a wide or abnormal S2 due to pulmonic valve timing, and S2 may remain relatively normal in those scenarios.

Pathological S2 reflects an abnormal second heart sound, most often due to delayed closure of the pulmonic valve (P2). When conduction to the right ventricle is slowed, as in a right bundle branch block, the pulmonic valve closes later, widening the interval between A2 and P2. Pulmonary stenosis also delays P2 directly by obstructing outflow. Together, these conditions commonly produce a clearly widened S2, heard as a pathological splitting at the left upper sternal border.

The other options don’t fit this pattern as neatly. Aortic stenosis mainly affects the aortic component (A2), often softening or delaying it rather than creating a wide, abnormal split. Mitral regurgitation and hypertrophic cardiomyopathy are not characteristically defined by a wide or abnormal S2 due to pulmonic valve timing, and S2 may remain relatively normal in those scenarios.