[Delayed-action disopyramide in the treatment of hyperkinetic ventricular arrhythmia. A randomized clinical...

The authors report the results of an open randomized study to compare the efficacy of oral slow-release and immediate-release disopyramide, in the treatment of patients with chronic stable ventricular arrhythmias, evaluated with two Holter recordings. Twelve patients, selected after positive acute intravenous test, had been randomly assigned to slow-release (500 mg/day) and immediate-release (400 mg/day) disopyramide. Ten days later, a Holter recording was performed and then all patients were treated with slow-release disopyramide (500 mg/day); After one month drug efficacy has been evaluated by Holter recording. Total ectopic beats and arrhythmic Lown modified score were the end points. Immediate-release disopyramide significantly reduced both total beats and arrhythmic score; the slow-release formulation did not modify total beats and reduced the arrhythmic score, but only at the first Holter control. One month later there was no significant difference in arrhythmic score either. Low plasma drug levels could explain these results in some patients.