Hypertrophic Obstructive Cardiomyopathy

A 28-year-old man presents with a two-year history of increasing dyspnea on strenuous exertion and is found to have hypertrophic cardiomyopathy, with a septal thickness of23 mm and a left ventricular outflow gradient of 80 mm Hg. There is no family history of hypertrophic cardiomyopathy or sudden death. Forty-eight-hour Holter monitoring shows infrequent premature ventricular contractions. How should this patient be treated?