Management of Atrial Fibrillation in Hypertrophic Cardiomyopathy.

Case Presentation: A 38-year-old man with hypertrophic cardiomyopathy (HCM) was referred for management of intermittent palpitations and exertional dyspnea with routine activities despite escalated β-blocker therapy. His initial examination was notable for a regular pulse at 72 bpm and harsh systolic murmur that increased with the Valsalva maneuver. A 12-lead electrocardiography revealed sinus rhythm with increased QRS voltage, repolarization abnormalities, and a QTc of 430 milliseconds. Echocardiography was notable for severe asymmetrical hypertrophy (septal thickness, 22 mm), normal systolic function, severe outflow tract obstruction (70 mm Hg), and left atrial (LA) enlargement. A 24-hour Holter monitor detected 6 minutes of rapid atrial fibrillation (AF) that coincided with his palpitations. Therapy was recommended with warfarin to prevent stroke and with disopyramide to minimize outflow tract obstruction and frequency of AF.