EFFECT OF LORCAINIDE ON EXPERIMENTAL ARRHYTHMIAS IN COMPARISON WITH OTHER ANTIARRHYTHMIC AGENTS

The antiarrhythmic action of lorcainide was studied on anesthesized rats and guinea pigs and compared with procainamide, verapamil, phenytoin and atropine. Intravenous bolus injection of lorcainide 3 mg/kg was shown to inhibit the cardiac arrhythmias induced by adrenaline, aconitine, BaCl₂ and ouabain, but not CaCl₂. The suppressive action of ⅳ atropine 0.1 mg/kg on adrenaline-induced rat arrhythmia was more potent than that of lorcainide. The suppressive effect of phenytoin (20 mg/kg ⅳ) on aconitine-induced arrhythmias was more significant than that of lorcainide. The effect of iv verapamil 1.25 mg/kg against BaCl₂-indueed arrhythmias was more potent than that of lorcainide; Lorcainide ⅳ 3 mg/kg inhibited ouabain-induced arrhythmias in guinea pigs. The dose required for ouabain to cause arrhythmias in lorcainide-group was more than that of verapamil, procainamide and phenytoin. Lorcainide 2.5×10^-6M also prolonged the functional refractory period of isolated cat left atria.