EFFICACY AND ADVERSE-EFFECTS OF MORACIZINE FOR VENTRICULAR-TACHYCARDIA

Moracizine (mean dose 792 +/- 84mg, range 600 to 900 mg/day) was evalu ated in 18 patients aged 62 +/- 7 years for spontaneous nonsustained ( n = 3) or sustained monomorphic (n = 12) ventricular tachycardia, card iac arrest (n = 1) or syncope (n = 2). All patients had spontaneous or induced sustained monomorphic ventricular tachycardia. Diagnoses incl uded coronary artery disease (n = 7) and dilated cardiomyopathy (n = 4 ), valvular heart disease (n = 2), myocarditis (n = 1), or a combinati on of these (n = 4). The mean left ventricular ejection fraction was 3 2 +/- 9% (range 15 to 52%). Prior to moracizine, antiarrhythmic drug a dministration included a mean of 2 +/- 1 trials with class IA (n = 17) , IB or IA + IB (n = 6) or IC (n = 5) antiarrhythmic drugs, or amiodar one (n = 3). Prior antiarrhythmic drugs were discontinued for either t he occurrence of noncardiac side effects or lack of efficacy. On morac izine, new sustained monomorphic ventricular tachycardia occurred in 3 patients with previous nonsustained ventricular tachycardia; spontane ous sustained monomorphic ventricular tachycardia recurred in 5 (and a ppeared to be worse in at least 2) patients with previous sustained mo nomorphic ventricular tachycardia; sustained monomorphic ventricular t achycardia was induced in all 11 patients undergoing repeat electrophy siology testing and was more difficult to terminate in 2 patients; 1 p atient with an implantable defibrillator died suddenly after receiving multiple implantable defibrillator shocks while on moracizine despite recent electrophysiology testing demonstrating satisfactory defibrill ation thresholds. Serious arrhythmic events occurred in 7 patients wit hin 7 days of therapy with the drug. In this patient population with i nducible or spontaneous sustained monomorphic ventricular tachycardia, moracizine was not effective and caused frequent, serious (usually ea rly) proarrhythmic effects.