Which lesion is classically described as a holosystolic murmur best heard at the apex with radiation to the axilla?

• A. Mitral regurgitation
• B. Aortic stenosis
• C. Tricuspid stenosis
• D. Pulmonary stenosis

Answer: (A)

Holosystolic murmur loudest at the apex with radiation to the axilla is the hallmark of mitral regurgitation. When the mitral valve fails to close properly, blood shunts backward from the left ventricle into the left atrium throughout systole. That regurgitant flow is heard best at the apex—the location of the mitral valve—and the jet often radiates to the axilla due to the direction of flow toward the left atrium and chest wall.

In contrast, aortic stenosis is a systolic ejection murmur heard best at the right upper sternal border with radiation to the carotids, not holosystolic. Tricuspid stenosis is a diastolic murmur at the left lower sternal border, and pulmonary stenosis is a systolic ejection murmur at the left upper sternal border.