[Electrophysiologic effects of serotonin on atrioventricular conduction in dogs]

In 12 anaesthetized dogs acute effects of serotonin on the atrioventricular conduction system were studied by obtaining intracardiac electrograms. The significant increase in the heart rate and decrease in aortic pressure elicited by an intravenous infusion of 50 mg/kg.min serotonin for 30 minutes were comparable to those observed in previous investigations. Our data indicate a serotonin induced acceleration of the sinus node pacemaker and atrioventricular conduction by direct and indirect mechanisms.