[Antiarrhythmic effect of disopyramid retard versus propranolol retard in ventricular extrasystole]

The antiarrhythmic effect of disopyramide retard (DR) in a dose of 2 X 300 mg/day, propranolol retard (PR) in one of 1 X 160 mg/day and placebo was compared in a randomized crossover study in patients with ventricular premature beats (VPB). 10 patients with VPB (Lown classes II-V) were given the drugs as follows: placebo I for 3 days. DR or PR for 7 days, placebo II for 5 days and PR or DR for 7 days. During every phase Holter ECG was registered over a period of 24 hours. Under DR 6 patients showed a favourable qualitative effect improving by at least one Lown class, while under PR only one patient did so. Under DR an over 80% reduction of VPB occurred in 6 patients and under PR in one patient. In all patients with any reduction of VPB this reduction was 79% under DR and 57% under PR. These results suggest that the antiarrhythmic effect of disopyramide in slow release preparations is comparable with that of disopyramide in standard capsule formulation given in the usual and more complicated regime with four divided doses. In the above mentioned (and still recommended) dose PR has no antiarrhythmic effect.