Long-term experience with sotalol in the treatment of complex ventricular arrhythmias.

Sotalol was given for extended therapy to 22 of 29 patients with frequent (greater than or equal to 30/hour) complex premature ventricular complexes (PVCs) who had participated in a short-term study of sotalol vs placebo. Open-label sotalol was given in individually titrated divided doses of 160 to 800 mg/day (median 323, mean 386 mg/day). Response was assessed at approximately 1, 6, and 12 months or until patient discontinuation. The period of sotalol therapy averaged 9 months (range, 0.2 to 22.7). At about 1 month, 13 (59%) of 22 patients showed effective control of arrhythmia. The median percentage change in total PVCs for individual patients at 1 month was -70% and for repetitive PVCs it was -95%. At about 6 months, 10 (45%) of the 22 patients continued to be successfully treated; at about 12 months, seven patients continued on sotalol, six (27%) successfully treated according to Holter criteria. Reasons for discontinuation included lack of efficacy in nine, adverse effects in four (fatigue in three, bradycardia with sinus pauses in one), and miscellaneous reasons in two. ECG PR and especially QTc intervals increased significantly during therapy (p less than 0.02, p less than 0.01, respectively). In summary, sotalol is a moderately effective antiarrhythmic agent in patients with complex PVCs, but during long-term therapy a rather high dropout rate was observed because of arrhythmia recurrence or adverse effects.