Oral tocainide versus disopyramide: a double-blind, randomized, crossover study of outpatients with stable ventricular premature beats.

Oral tocainide and disopyramide were compared in a double-blind, crossover trial in 10 outpatients with stable ventricular premature beats (VPBs). Efficacy was assessed by suppression of VPB activity and reduction of VPB grade during an exercise test and an 18-h Holter recording. An estimate of variance of VPB activity was obtained from two separate placebo periods, and a 95% confidence limit for VPB suppression was calculated. During Holter recording, both drugs produced a significant reduction in VPB frequency and grade (p less than 0.05). During the exercise challenge, tocainide produced a reduction in VPB frequency and grade, but this did not reach statistical significance; VPB frequency was unaltered by disopyramide, but VPB grade was significantly reduced (p less than 0.01).