Cibenzoline for symptomatic ventricular arrhythmias: a prospective, randomized, double-blind, placebo controlled trial and a long term open label study.

To assess the efficacy and safety of cibenzoline, 18 patients with symptomatic premature ventricular complexes (30/h or more) on baseline 48 h Holter monitors were randomized to oral cibenzoline versus placebo. The cibenzoline and placebo doses were increased from 130 to 160 mg bid after one week if premature ventricular complex (PVC) suppression was less than 75%. The double-blind placebo controlled phase (phase 1) lasted for two weeks prior to the open label long term study (phase 2). Efficacy was defined as suppression of at least 75% PVCs, 85% couplets and 90% ventricular tachycardia on follow-up 48 h Holter monitoring. At the six month mark of phase 2, patients were placed on placebo for seven days to evaluate for spontaneous resolution of PVCs. Of the seven patients on cibenzoline in phase 1, four had a positive response, one had partial control (73% suppression of PVCs) and two noted dizziness and withdrew. Of the 11 patients randomized to placebo, nine noted no change, two had a significant decrease in PVCs and one noted dizziness and withdrew. Fifteen patients were enrolled in phase 2 on open label cibenzoline at 130 to 160 mg bid. At a mean follow-up of 17 +/- 4 months (range 12 to 25), eight patients had control of symptomatic ventricular arrhythmias without adverse effects, three patients did not respond to cibenzoline, one had PVC recurrence after initial control on cibenzoline, one died of myocardial infarction without arrhythmias, one had spontaneous resolution of PVCs and one was withdrawn because of poor compliance. In conclusion, cibenzoline is effective in controlling symptomatic PVCs and is moderately well tolerated.