Human Electropharmacology of Tocainide, a lidocaine congener

The electropharmacology of tocainide, an orally active congener of lidocaine, was evaluated in 10 patients with coronary artery disease. Electrophysiologic measurements including sinus nodal recovery time, sinoatrial conduction time, intraatrial conduction time, atrial, atrioventricular (A-V) nodal and ventricular refractory periods and intraventricular conduction time were obtained before and after intravenous infusion of tocainide. At blood levels shown to be effective against ventricular arrhythmias, tocainide produced no statistically significant changes in the electrophysiologic measurements, although occasional marked individual effects were observed. No side effects were observed during these studies. No adverse effects on A-V conduction were observed in patients with an intraventricular conduction disturbance or a prolonged control H-V interval. Thus, plasma tocainide concentrations effective in the therapy of ventricular arrhythmias exert no adverse effects on cardiac electrophysiologic properties in patients with coronary artery disease.