Comparative study of cibenzoline and diphenyhydantoin antiarrhithmic actions in digitalis-induced ventricular arrhythmias

Abstract

Cibenzoline, a new antiarrhythmic drug, was studied in dogs after induction of experimentally digitalis-induced ventricular arrhythmias. Diphenyhydantoin was used for comparison. Sixty adult healthy mongrel dogs of both sexes were anesthetized with sodium thiopental and maintained under artificial ventilation. Electrical cardiac activity was continuosly monitored by electrocardioscope and electrocardiogram was periodically registered. In thirty animais, ventricular arrhythmias were induced by ouabain: ten dogs were used as controls and ventricular arrhythmias' evolution was observed without treatment; cibenzoline was administered in ten dogs after stabilization of ventricular arrhythmias; and the last ten dogs were treated with diphenyhydantoin. In thirty animais, ventricular arrhythmias were induced by C-lanatoside: ten dogs were used as contrels and ventricular arrhythmias'natural evolution was observed; ten dogs received cibenzoline after stabilization of ventricular arrhythmias; and the last ten dogs were treated with diphenyhydantoin. Animais used as control were observed during 120 minutes after stabilization of ventricular arrhythmias; observation was shortned when dogs died before this time elapsed. When cibenzoline or diphenyhydantoin were used, animais were observed during 120 minutes after the last antiarrhythmic agent's administration. The doses of cibenzoline ranged from 4,0 to 12,0 mg/Kg and diphenyhydantoin doses ranged between 3,57 to 35,71 mg/Kg. Both antiarrhythmic drugs were more efficient in reversion of arrhythmias induced by ouabain. Considering ouabain-induced ventricular arrhythmias, rate of reversion was higher when cibenzoline was tested than when diphenyhydantoin was administered.