A 17 yo male presents for follow up on a “fainting” episode that occurred during football practice at the end of a running exercise. He states, “I do not know what happened. We finished a set of running sprints and next thing I knew, I was on the ground.” He denies injury from the event and history of prior episodes. His physical examination reveals a crescendo-decrescendo systolic murmur heart best at the apex, increasing in intensity with position change from supine to standing position. &n...