Metoprolol versus sotalol in the treatment of sustained ventricular tachycardia.

The efficacy of sotalol in the treatment of sustained ventricular arrhythmias has been proved; however, whether its antiarrhythmic effect is due to a beta-blocking activity, a class III antiarrhythmic activity, or a combination of both is not known. We conducted a prospective randomized study to compare the effects of metoprolol, a "pure" beta-blocking agent, and of sotalol, a beta-blocking agent with additional class III antiarrhythmic properties, in 34 consecutive patients with documented sustained monomorphic ventricular tachycardia (VT) unrelated to transient causes. After undergoing baseline programmed electrical stimulation (PES-1) to assess arrhythmia inducibility, the patients were randomly assigned to a (double-blind) treatment of either metoprolol (16 patients) or sotalol (18 patients). Before the chronic regimen was initiated, arrhythmia inducibility was reassessed after the intravenous administration of either 0.15 mg/kg metoprolol or 1.5 mg/kg sotalol (PES-2), according to drug assignment. During the chronic oral regimen, a third PES (PES-3) was performed after a median follow-up of 72 days. Resting and exercise ECG, Holter monitoring and echocardiography were performed at baseline and during follow-up. During a 2-year follow-up, a non-fatal arrhythmia recurred in 1 patient of the metoprolol arm and in 5 patients of the sotalol arm; 1 patient in the latter group died suddenly 2 months after the recurrence, while receiving amiodarone therapy. Intention-to-treat analysis showed no difference in the incidence of arrhythmia recurrence, sudden death, or total mortality between the two groups. During PES-1, a sustained ventricular arrhythmia was inducible in 18 of 34 patients (53%), 8 in the metoprolol and 10 in the sotalol arm.(ABSTRACT TRUNCATED AT 250 WORDS)