[Tachycardia-induced cardiomyopathy: a case report].

A 30-year-old man with chronic sustained ventricular tachycardia (VT) lasting more than seven years was treated with propranolol, 30 mg/day. This resulted in controlled cardiac rates of 90 to 130/min during sleep, and 100 to 195/min while awake. However, he experienced Adams-Stokes attacks twice, in September and December, 1986. During the second attack, ambulatory heart monitoring showed his VT rate of 212/min. An electrophysiological study revealed that the VT focal point was in the lower-mid region of the interventricular septum in the right ventricle. The VT was characterized by abnormal enhanced automaticity. This VT could not be interrupted either by single or multiple combinations of antiarrhythmic drugs. Cardiac catheterization revealed a diffusely enlarged hypokinetic left ventricle, even at the rate of 120/min VT (EF 27%, C.I. 2.3 l/min/m2). Because of his severe hemodynamic state, we performed electrical catheter ablation successfully. After the ablation, his left ventricular wall motion gradually improved. Nine months after the ablation, his left ventricular diastolic dimension decreased from 64 to 48 mm and the left ventricular systolic dimension decreased from 57 to 28 mm on M-mode echocardiography, while ejection fraction increased from 27 to 73% on the left ventriculography. Bi-ventricular myocardial biopsy specimens obtained prior to the ablation revealed only cellular hypertrophy of varying degrees, and vacuole degeneration consistent with non-specific cardiomyopathy. However, nine months after the ablation, these findings were no longer present. Thus, this case was considered tachycardia-induced cardiomyopathy initiated by VT, lasting many years.