METOPROLOL VERSUS SOTALOL IN THE TREATMENT OF SUSTAINED VENTRICULAR-TACHYCARDIA

The efficacy of sotalol in the treatment of sustained ventricular arrh ythmias has been proved; however, whether its antiarrhythmic effect is due to a p-blocking activity, a class III antiarrhythmic activity, or a combination of both is not known. We conducted a prospective random ized study to compare the effects of metoprolol, a ''pure'' beta-block ing agent, and of sotalol, a beta-blocking agent with additional class III antiarrhythmic properties, in 34 consecutive patients with docume nted sustained monomorphic ventricular tachycardia (VT) unrelated to t ransient causes. After undergoing baseline programmed electrical stimu lation (PES-1) to assess arrhythmia inducibility, the patients were ra ndomly assigned to a (double-blind) treatment of either metoprolol (16 patients) or sotalol (18 patients). Before the chronic regimen was in itiated, arrhythmia inducibility was reassessed after the intravenous administration of either 0.15 mg/kg metoprolol or 1.5 mg/kg sotalol (P ES-2), according to drug assignment. During the chronic oral regimen, a third PES (PES-3) was performed after a median followup of 72 days. Resting and exercise EGG, Holter monitoring and echocardiography were performed at baseline and during follow-up. During a 2-year follow-up, a nonfatal 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 the rapy. Intention-to-treat analysis showed no difference in the incidenc e of arrhythmia recurrence, sudden death, or total mortality between t he two groups. During RES-I, a sustained ventricular arrhythmia was in ducible in 18 of 34 patients (53%), 8 in the metoprolol and 10 in the sotalol arm. As compared with oral metoprolol, oral sotalol significan tly reduced arrhythmia inducibility, but this finding did not correlat e with clinical outcome. Neither drug proved superior in preventing th e recurrence of spontaneous ventricular arrhythmia or spontaneous or i nduced ischemic events. Logistic regression showed that gender, age, l eft ventricular ejection fraction (LVEF), the number of stenotic coron ary arteries, and the occurrence of ischemic events did not predict th e outcome. Results suggest that metoprolol is as efficacious as sotalo l in the treatment of stable monomorphic VT. Whether the treatment of such patients with a pure beta-blocking agent, with a class III antiar rhythmic agent, or with a drug combining both properties may more rele vantly affect the clinical outcome in these patients remains to be inv estigated.