Comparison of electrophysiologic and hemodynamic effects of SD-3212, a new antiarrhythmic drug, and flecainide in a canine myocardial infarction model.

Electrophysiologic and hemodynamic effects of SD-3212, a new antiarrhythmic drug, were examined and compared with those of flecainide, a class Ic antiarrhythmic drug, in a canine myocardial infarction model. The doses of SD-3212 were 1 mg/kg bolus injection followed by 0.1 mg/kg/min infusion and 3 mg/kg bolus injection followed by 0.3 mg/kg/min infusion, while those of flecainide were 0.3 mg/kg bolus injection followed by 0.03 mg/kg/min infusion and 1 mg/kg bolus injection followed by 0.1 mg/kg/min infusion. SD-3212 at the high dose prolonged the effective refractory period and QT interval, and depressed ventricular delayed conduction. Flecainide at the high dose also prolonged the effective refractory period and depressed ventricular delayed conduction. Flecainide reduced a maximal rate of rise of left ventricular pressure at the high dose, while SD-3212 did not significantly change it. Neither of the drugs significantly affected mean arterial blood pressure or cardiac output. Thus, SD-3212 may produce antiarrhythmic effects with less cardiac depressant effect than flecainide.