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 antiarrhy thmic drug, were examined and compared with those of flecainide, a cla ss Ic antiarrhythmic drug, in a canine myocardial infarction model. Th e doses of SD-3212 were 1 mg/kg bolus injection followed by 0.1 mg/kg/ min infusion and 3mg/kg bolus injection followed by 0.3mg/kg/min infus ion, while those of flecainide were 0.3mg/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 r efractory period and QT interval, and depressed ventricular delayed co nduction. Flecainide at the high dose also prolonged the effective ref ractory period and depressed ventricular delayed conduction. Flecainid e reduced a maximal rate of rise of left ventricular pressure at the h igh dose, while SD-3212 did not significantly change it. Neither of th e drugs significantly affected mean arterial blood pressure or cardiac output. Thus, SD-3212 may produce antiarrhythmic effects with less ca rdiac depressant effect than flecainide.