The prevalence of proarrhythmic events during moricizine therapy and their relationship to ventricular function.

The prevalence of proarrhythmic events during moricizine therapy was studied in 144 patients who were treated for symptomatic ventricular tachycardia or ventricular fibrillation. The overall incidence of proarrhythmia was 15.3%. (Twenty-two patients exhibited 23 events.) Ventricular fibrillation occurred in six patients (which led to three deaths), incessant ventricular tachycardia occurred in seven, and new sustained ventricular tachycardia in four. Patients with proarrhythmia had significantly lower left ventricular ejection fraction (24% vs 39%; p less than 0.0001), higher prevalence of congestive heart failure (68% vs 36%; p less than 0.005), and higher incidence of previous proarrhythmia (45% vs 9%; p less than 0.0001). No significant difference between the two groups was found in respect to age, arrhythmia at presentation, underlying heart disease, moricizine dose, or concomitant drug therapy.