[Effect of Bunaftine on the aconitine-induced atrial arrhythmias in the dog]

Bunaftine has a quinidine-like vagolytic effect and does not act as a beta-blocking agent. Its effect on aconitine-induced atrial fibrillation in the dog was examined. It led to suproventricular tachycardia in all cases, but re-established the sinus rhythm in only 5/15. It is felt that this lack of success is attributable to the slowing of the frequency of the primary pacemaker on the part of the drug. Slowing down of atrioventricular and intraventricular conduction by Bunaftine was revealed by lengthening of the P-R interval and widening of the Q-RS complex. Decreased blood pressure following administration of the drug appears to be due to reduction of heart rate rather than altered myocardial inotropism or peripheral resistance.