Propafenone versus disopyramide: A double‐blind randomized crossover trial in patients presenting chronic ventricular arrhythmias

In vitro and in vivo electrophysiological studies have shown that propafenone could be classified as a class I antiarrhythmic agent. The aim of this study was to investigate the short‐term antiarrhythmic efficacy and safety of propafenone in 10 patients compared to disopyramide in a double‐blind randomized protocol. Included patients suffered from ventricular arrhythmias with at least 60 ventricular premature beats (VPB) per hour refractory to at least two other antiarrhythmic agents. At the end of the control period and of the two treatment periods during which patients received either propafenone (300 mg three times a day) or disopyramide (200 mg three times a day), clinical examination, Holter recordings, electrocardiogram, and clinical laboratory tests were performed. The PR interval and the QRS interval were significantly increased with propafenone, but not with disopyramide. The cQT interval was not significantly changed by either propafenone or disopyramide. Heart rate was decreased with propafenone (p<0.05) with no change in the diurnal/nocturnal circadian ratio variation. Heart rate was significantly decreased with disopyramide only during the day. Five of nine patients in the propafenone group and two of nine patients in the disopyramide group showed a reduction in ventricular premature beats greater than 80%. Total resolution of severe arrhythmias (repetitive events) was seen in 5 of 8 patients with propafenone; 2 of 8 with disopyramide. Adverse events, when they occurred, were mild (visual disturbances, epigastric discomfort, changes in taste perception, transient atrioventricular block with propafenone, and photophobia with disopyramide), and did not require reduction or discontinuation of study drug. Considering these results, propafenone is expected to be an efficient antiarrhythmic drug in the treatment of severe ventricular arrhythmias.