Comparison of the electrophysiologic effects of intravenous and oral lorcainide in patients with recurrent ventricular tachycardia.

Publisher Website
Google Scholar
Abstract
The electrophysiologic effects of i.v. lorcainide (2.2 mg/kg) in 10 patients were compared with the electrophysiologic effects of oral lorcainide (mean dose 400 mg/day for 8 days) in 11 patients, all with recurrent ventricular tachycardia that could be induced with programmed stimulation. I.v. and oral lorcainide resulted in similar prolongation of the QRS, QT and HV intervals, but only oral lorcainide resulted in prolongation of the AH interval and atrial and ventricular effective refractory periods. After both oral and i.v. lorcainide, ventricular tachycardia could still be induced, but the arrhythmia was slower and better tolerated hemodynamically. The mean plasma lorcainide level during a maintenance i.v. infusion was 1254 .+-. 662 ng/ml compared with a lorcainide level of 562 .+-. 41 ng/ml and a norlorcainide level of 1212 .+-. 653 ng/ml after oral dosing. No norlorcainide was detected in plasma after i.v. lorcainide. Apparently, the short-term electrophysiologic effects of i.v. lorcainide may be different from those of short-term therapy with the oral drug. These differences should be considered during short-term studies of lorcainide.