Lorcainide in patients with refractory ventricular tachyarrhythmia.

Lorcainide, a new antiarrhythmic agent with local anesthetic or membrane-stabilizing properties similar to those of quinidine, was tested in 76 patients with diverse types of heart disease and recurrent ventricular tachycardia or ventricular fibrillation. Lorcainide was administered for 72 to 96 hours in a dose ranging from 200 to 400 mg daily. Evaluation of drug efficacy involved ambulatory monitoring and exercise stress testing in 60 patients who had high grade ventricular arrhythmia. Invasive electrophysiologic testing was carried out in the remaining 16 patients who exhibited infrequent ventricular ectopic activity during control studies. Lorcainide was effective in 21 (38%) of 56 patients evaluated for suppression of ventricular ectopic activity and in 6 (40%) of 15 who had invasive testing. In five patients, the drug was discontinued because of toxic reactions. Thus, 27 (38%) of the 71 patients who completed the drug study responded to lorcainide. Side effects, reported by 42 patients (55.3%), consisted primarily of insomnia and gastrointestinal symptoms; 7 experienced aggravation of arrhythmia. Fifteen patients were discharged while receiving lorcainide therapy, but in four the treatment was discontinued after 2 months because of side effects. Three patients died, one suddenly. It is concluded that lorcainide is of value in a small subset of patients with life-threatening ventricular arrhythmias who have proven refractory to conventional drugs. Its usefulness is limited by the high frequency of insomnia.