CLINICAL-STUDY OF NIBENTAN - NEW CLASS-II I ANTIARRHYTHMIC DRUG .3. EFFICACY IN PATIENTS WITH VENTRICULAR ARRHYTHMIAS - ARRHYTHMOGENIC EFFECTS

Efficacy of a new class III antiarrhythmic drug nibentan for suppressi on of ventricular arrhythmias and its proarrhythmic effects in various cardiac rhythm disturbances were studied in 29 patients with frequent high grade ventricular premature beats and in 42 patients with atrial premature beats, supraventricular tachycardia, atrial fibrillation an d flutter. In 54 patients underlying heart disease was revealed and in 17 patients arrhythmias were idiopathic. None of the patients had con duction disturbances or heart failure. Nibentan was injected intraveno usly as 1 - 3 boluses with 15 minute intervals. Total dose was 0, 125 - 0,5 mg/kg. Methods of investigation included conventional 12-lead an d Holter 24-hour ECG and ECG monitoring in coronary care unit. Nibenta n produced pronounced antiarrhythmic effect in 57% of patients with fr equent and coupled ventricular premature beats and with paroxysmal uns ustained ventricular tachycardia. Rate of proarrhythmic effects in pat ients with ventricular arrhythmias was high and average effective and average arrhythmogenic doses were equal. These data precluded recommen dation of a wide use of the drug in these rhythm disturbances. Proarrh ythmic effects were observed in 8% of patients with supraventricular t achycardia, atrial fibrillation and flutter mainly during periods of s inus rhythm. No proarrhythmic effects were registered in patients with paroxysmal supraventricular arrhythmias.