Successful electrical cardioversion in a massive concentric hypertrophic cardiomyopathy with atrial fibrillation.

A 59-year-old man with a known history of nonobstructive hypertrophic cardiomyopathy and chronic atrial fibrillation was admitted to our clinic with weakness, palpitation, and exertional dyspnea. Electrocardiogram showed atrial fibrillation with high ventricular rate (120 beats per minute), intraventricular conduction delay, and left ventricular (LV) hypertrophy with ST-segment depression and inverted T waves. A transthoracic echocardiogram showed massive LV concentric hypertrophy. Although there was no gradient increase in the LV outflow tract, marked turbulent flow was seen in midventricular region by colored Doppler echocardiography. On the fourth day of admission, transesophageal echocardiography was done and showed no thrombus in the left atrium. Electrical cardioversion with 100 J was applied to the patient, and atrial fibrillation was returned to sinus rhythm. His control Doppler echocardiogram revealed peak systolic resting gradient of 54 mm Hg, with an increase to 84 mm Hg at Valsalva maneuver at the LV outflow. Cardiac magnetic resonance showed concentric LV hypertrophy with a 35-mm thickness in diastole, mild scar tissue in LV anterior wall midapical segments, and right ventricle wall thickness with a 10 mm in diastole. There was no bradycardia or tachycardia in 24-hour Holter and exercise electrocardiographic testing.