Effects of carocainide (770207) on canine cardiac automaticity.

The benzofuran derivative carocainide is a new class I antiarrhythmic drug which has been shown to prevent and stop experimental ventricular arrhythmias. The effects of this drug on different types of cardiac automaticity were investigated by experimental models using "in situ" dogs' hearts. Complete A-V block was produced by local formaldehyde injection into the A-V junction. Carocainide at doses of 2.5, 5 and 7.5 mg/kg body weight i.v. produced the following effects: a significant and dose-related slowing of the idioventricular rate; a non-significant change of the sinus rate at 2.5 and 5 mg/kg b.w.; and a significant decrease of the total number of triggered ventricular beats induced by ventricular pacing during slow norepinephrine infusion. Our results suggest that carocainide could be a safe and effective drug for the treatment of ventricular arrhythmias.