USMLE Step 1 - Question 28

An 18 year old male dies suddenly during a track and field event. During a recent sports physical he was noted to have a II/VI systolic crescendo-decreshendo murmur at the right upper sternal border that became louder with Valsalva. A paradoxical split S2 heart sound was heard. Which of the following is his likely diagnosis?

A. Congenital coronary anomaly

B. Comotio cordis

C. Idiopathic hypertrophic subaortic stenosis

D. Dilated cardiomyopathy