A 17 year old male with no significant past medical history pasess out while running. He states that he was feeling a little dizzy prior to the event, but no chest pains or palpitations. His blood pressure is 115/85, heart rate 80, respirations 12, and he is afebrile. His physical examination reveals normal lung sounds, a II/VI mid-sytolic creshendo-decreshndo murmur is heard at the right upper sternal border which increases in intensity with Valsalva, an S4 heart sound is also present. Laboratory studies are normal. What is his most likely diagnosis?
A. Congenital pulmonic valve stenosis
B. Hypertrophic obstructive cardiomyopathy
C. Congential aortic valve stenosis
D. Commotio cordis
E. Atrial setpal defect