Randomized double-blind study of intravenous tocainide versus lidocaine for suppression of ventricular arrhythmias after cardiac surgery.

To compare the therapeutic efficacy and safety of intravenous tocainide with that of intravenous lidocaine in patients with ventricular arrhythmias after cardiac surgery, 25 patients were randomized to either agent in a double-blind manner. Tocainide was given in 16 patients as a 250 mg bolus followed by a loading infusion of 500 mg over 15 minutes and a maintenance infusion of 33.3 mg/min. Lidocaine was administered in 9 patients as a 100 mg bolus followed by a loading infusion of 60 mg over 15 minutes and a maintenance infusion of 1.4 mg/min. Therapy was continued for 24 hours in initially responding patients. With analysis of 24-h taped electrocardiograms it was found that single premature ventricular complexes (PVCs) were suppressed by tocainide by more than 80% in 94% of patients and by lidocaine in 75% of patients (p = NS). Couplets and ventricular tachycardia events were eliminated in all patients by either drug. Multiform PVCs were abolished in 94% of the patients after tocainide and in 75% after lidocaine (p = NS). Average overall success over the 24 hours with more than 80% suppression of single PVCs and simultaneous elimination of higher forms of arrhythmia was 71% with tocainide and 59% with lidocaine (p = NS). Adverse effects were negligible, with only one patient in the lidocaine group developing diaphoresis without necessitating termination of therapy. Treatment rapidly produced and then maintained blood levels of 4-10 mg/l for tocainide and 1-4 mg/l for lidocaine. We conclude that intravenous tocainide is well tolerated and has comparable efficacy to lidocaine in the acute therapy of postcardiac surgery ventricular arrhythmias.