A 6-month-old boy is brought to your pediatric cardiology clinic for evaluation of a murmur that was heard during a routine check-up by his primary care physician. His mother reports that he is healthy and active, with no episodes of shortness of breath or frequent infections. On physical examination, he appears well-nourished and appropriately sized for his age. Auscultation reveals a harsh, holosystolic murmur at the left lower sternal border. There is no cyanosis or clubbing. An echocardiogram reveals a small, isolated ventricular septal defect (VSD) with a left-to-right shunt. What is the most appropriate next step in the management of this patient?
