A 32-year-old man presents to the clinic complaining of exertional dyspnea and occasional palpitations. He reports that his symptoms have progressively worsened over the last six months. Two weeks ago, he experienced an episode of severe lightheadedness and felt as though he might pass out while playing basketball with his friends. His medical history is unremarkable, and he takes no medications. He does not use tobacco or illicit drugs. His family history is notable for a paternal uncle who died suddenly of an unknown cardiac condition at the age of 35.

He appears well-developed and is in no acute distress. He is afebrile. His blood pressure is 115/70 mmHg with a heart rate of 68 bpm.