A 15-year-old boy presents to the clinic with his parents, complaining of increasing fatigue and shortness of breath during soccer practice over the past four months. He was diagnosed with a perimembranous ventricular septal defect shortly after birth. The defect was initially deemed small, and he was managed conservatively as he remained asymptomatic throughout childhood. His past medical history is otherwise unremarkable. He takes no daily medications and has no known drug allergies. He denies any chest pain, syncope, palpitations, or recent febrile illnesses. His family history is notable for a grandfather who underwent coronary artery bypass grafting at age 65.

He appears comfortable at rest and is in no acute distress. Well-appearing, no cyanosis. Afebrile. Blood pressure is 118/65 mmHg with a regular heart rate of 84 bpm and a respiratory rate of 16 breaths per minute.