A 24-year-old man presents to the cardiology clinic with a 1-year history of progressively worsening dyspnea on exertion. He is a college student who has become concerned because he can no longer keep up with his peers during recreational basketball games, feeling easily fatigued and short of breath. His past medical history is notable for Tetralogy of Fallot, for which he underwent a complete surgical repair with a transannular patch at 3 years of age. He has had intermittent cardiology follow-up since then but has been lost to care for the past 5 years. He takes no regular medications and has no known drug allergies. He denies chest pain, palpitations, or syncope. He is a non-smoker and drinks alcohol socially.