The antiarrhythmic effects of controlled release disopyramide phosphate and long acting propranolol in patients with ventricular arrhythmias

The antiarrhythmic effect of slow-release disopyramide phosphate (DR) 300 mg twice daily and of long-acting propranolol (PR) 1 × 160 mg daily was compared in a randomized cross-over study in patients with premature ventricular beats (PVB). 12 patients with PVB (Lown Classes II–V) were given: placebo I for 3 days, DR or PR for 7 days, placebo II for 5 days and PR or DR for 7 days. During each study phase Holter-ECG recordings were taken over a period of 24h. With DR 6 patients showed a positive qualitative effect, improving by at least one Lown class, whereas only 2 patients did so with PR. With DR reduction of PVB>80% occurred in 7 patients, and with PR in 2 patients. In all patients with any reduction in PVB, the median decrease was 85% with DR and 59% with PR. The overall results suggest that the antiarrhythmic effect of disopyramide phosphate in the slow-release preparation is at least satisfactory and comparable to that of disopyramide phosphate in the standard capsule formulation given in the usual and more complicated regime of four divided doses. The antiarrhythmic effect of PR in the recommended dose as given was not convincing.