Atrial fibrillation and ventricular dysfunction: a vicious electromechanical cycle.

Case Presentation: A 44-yearold man with a history of hypertension presented with New York Heart Association class IV congestive heart failure (CHF) and atrial fibrillation (AF) with rapid ventricular response (160 beats per minute) and unknown onset. Transthoracic and transesophageal echocardiography demonstrated severe global left ventricular (LV) dilatation, LV ejection fraction (LVEF) of 20%, and a mobile thrombus in the left atrial appendage but no evidence of coronary artery disease or valvular heart disease. After treatment with furosemide, digoxin, metoprolol, lisinopril, and warfarin, a repeat transesophageal echocardiogram 4 weeks later showed resolution of the thrombus. Subsequent attempts at cardioversion were unsuccessful despite treatment with sotalol hydrochloride and amiodarone. An average heart rate of less than 80 beats per minute was achieved after treatment with diltiazem hydrochloride, metoprolol, and digoxin. Three months later, the patient’s LVEF was 55% with mild LV enlargement.