Efficacy and plasma concentrations of SC-36602 in canine models of ventricular arrhythmia.

The antiarrhythmic effectiveness of a new class I agent, SC-36602, was evaluated in two canine models of ventricular arrhythmia. In a Harris coronary ligation-induced arrhythmia model, SC-36602 significantly reduced ectopic rate at doses of 8 mg/kg i.v. and 15, 20 and 30 mg/kg per os. In a ouabain-induced arrhythmia model, a 9 mg/kg i.v. dose of SC-36602 had a sustained (greater than or equal to 60 min) antiarrhythmic effect. The approximate plasma concentration of SC-36602 necessary for measurable antiarrhythmic activity was estimated to be 2-7 micrograms/ml after either i.v. or oral administration. No adverse cardiovascular or central nervous system effects were observed in conscious or anesthetized dogs in response to SC-36602.