Electrophysiologic effects of bepridil in patients with refractory ventricular tachycardia assessed by programmed electrical stimulation

The effect of intravenous bepridil, a new calcium antagonist with class I and III properties, was tested in 21 patients with sustained ventricular tachyarrhythmias refractory to a mean of five antiarrhythmic agents as assessed by programmed right ventricular stimulation. At control electrophysiologic study without antiarrhythmic agents, sustained monomorphic ventricular tachycardia (VT) was initiated in 20 patients and ventricular fibrillation (VF) was initiated in one patient. After 3 mg/kg of bepridil was administered, VT was still inducible in 19 patients (3 patients had self-terminating VT); the other 2 patients had no inducible VT after bepridil. Bepridil prolonged significantly the QTc interval, the effective refractory period, and the cycle length of induced ventricular tachycardia. Two patients with no inducible VT after intravenous bepridil were placed on oral bepridil (300 mg/day). One patient died suddenly and one patient died of progressive heart failure. The results seem to indicate that the efficacy of bepridil in patients with refractory ventricular tachycardia is limited.