Cardiac Resynchronization Therapy in Patients with Ebstein's Anomaly.

Ebstein's anomaly is a rare congenital heart disease characterized by apical displacement of the septal and posterior tricuspid valve leaflets. It is often complicated with left ventricular (LV) dysfunction as well as right-sided abnormalities. On the other hand, in the presence of LV dysfunction, right ventricular pacing is likely to aggravate the diseased LV function, which is termed pacemaker-induced cardiomyopathy. Thus, deteriorating effects of RV pacing on cardiac function might be enhanced and result in pacemaker-induced cardiomyopathy in patients with Ebstein's anomaly, even if they have preserved LVEF. Cardiac resynchronization therapy (CRT) is effective for the treatment of pacemaker-induced cardiomyopathy, and we present the first case of effect of CRT on pacemaker-induced cardiomyopathy associated with Ebstein's anomaly.