Which murmur can present as a late-peaking systolic murmur with an ejection click?

• A. Aortic stenosis
• B. MVP
• C. Atrial septal defect
• D. Mitral regurgitation

Answer: (A)

Murmur timing and valve opening sounds reveal how the valve is opening and how severe the obstruction is. A late-peaking systolic murmur means the sound reaches its maximum intensity toward the end of systole, which happens when outflow obstruction is more severe. An ejection click is a brief, high-pitched sound heard at the start of systole as a semilunar valve abruptly opens; this is often heard with a diseased aortic valve, especially when opening is sudden, as with bicuspid or calcified valves. Taken together, a late-peaking systolic murmur with an ejection click is characteristic of aortic stenosis.

Other patterns don’t fit as well: mitral valve prolapse has a midsystolic click with a late systolic murmur but not an ejection click; an atrial septal defect has a fixed S2 split with a systolic flow murmur at the left upper sternal border; mitral regurgitation is holosystolic.