[Comparative study of quinidine and disopyramide in the treatment of stable ventricular extrasystole]

The antiarrhythmic efficiency of quinidine arabogalactan-sulphate (QAGS) and disopyramide were determined in 38 patients showing chronic, stable frequency premature ventricular beats (PVB). The study which was carried out in 4 medical Centers, used a longitudinal cross-over design. After a baseline evaluation which consisted of two 24 hours electrocardiograms, the patients were randomised to one of the two drugs during a period of 6 or 7 days. The drug sequence were followed by a placebo sequence. A 24 hours electrocardiogram was performed at the end of each sequence. The daily doses were equivalent to 660 mg of quinidine base for QAGS and 600 mg for disopyramide. Among the 38 patients who entered in the study, 32 went through each sequence of the test. The average number of PVB was significantly reduced by QAGS and disopyramide (p less than 0.0001). With QAGS 18 patients had more than 65 p. 100 reduction of PVB and 12 of them more than 80 p. 100. With disopyramide, 14 patients had more than 65 p. 100 reduction of PVB and 12 of them more than 80 p. 100. There was no statistical difference in the overall efficiency of the two drugs. Three patients died, one from myocardial reinfarction, one from ventricular fibrillation; in one other case, the cause of the death remained undetermined. QAGS was better tolerated than disopyramide; adverse effects occurred in 6 patients with QAGS and in 10 with disopyramide. The responsibility of disopyramide in the occurrence of two severe ventricular arrhythmia may be questioned.