Recurrent ventricular tachycardia in man: Evaluation of disopyramide therapy by intracardiac electrical stimulation

Effectiveness of disopyramide phosphate therapy was examined on 12 patients with recurrent ventricular tachycardia (VT) resistant to standard antiarrhythmic agents. Prior to initiation of treatment with disopyramide, a control electrophysiological study demonstrated that reproducible initiation of VT was possible in 10/12 patients by programmed intracardiac electrical stimulation. In 1 other patient frequent episodes of VT were induced only once. In 8/12 patients the effects of intravenously administered disopyramide on VT were examined during the study. VT slowed in 6/8 patients, accelerated in 1 patient and was unchanged in 1. 5 patients tolerated VT sufficiently to undergo drug infusion during ongoing arrhythmia, and in 4/5 patients tachycardia was terminated. Subsequently successive dose levels of disopyramide were administered orally to all 12 patients. In 7/10 patients with reproducible VT in the laboratory, drug effectiveness was tested at 2 or more oral drug levels by attempting to reinduce arrhythmia using intracardiac stimulation. In 3 patients only 1 restudy was carried out during oral treatment. During follow-up (18±9 mth), 4/5 patients in whom disopyramide therapy prevented reinduction of VT in the laboratory remain arrhythmia-free, while 1 patient had a single recurrence. Of 6 patients in whom prevention of induced VT was not demonstrated, 1 is arrhythmia free, 3 had recurrence and 2 died. In 1 patient disopyramide failed to control VT in-hospital, and this patient died.