[Efficacy and tolerance of disopyramide in arrhythmia associated with sinus node dysfunction].

The aim of this study was to assess the effect of delayed release Disopyramide 500 mg daily on sinus node function in 12 subjects with sinus node dysfunction and supraventricular and/or ventricular excitability. An ECG, Holter monitoring and electrophysiological studies of sinus node function with an oesophageal electrode were performed before and after 5 days treatment. The drug had to be discontinued in 1 patient because of urinary retention. The Disopyramide suppressed the clinical tachyarrhythmias in 8 out of the 11 subjects. The maximal sinus pause observed on Holter monitoring did not change significantly. It only increased in one subject. The mean sinus cycle length during electrophysiological study slightly decreased but there was a global increase in sinoatrial conduction time from 309 +/- 164 to 413 +/- 125 msec and of the corrected sinus mode recovery time from 470 +/- 168 to 605 +/- 303 msec. However, these changes were not significant. This study of delayed released Disopyramide shows a discordance between the tendency for sinus node function to deteriorate when assessed by electrophysiological studies and good clinical tolerance as assessed by Holter monitoring in the bradycardia-tachycardia syndrome.