Long-term sotalol therapy in patients with arrhythmias.

Sotalol is a pure beta-adrenergic receptor antagonist. The present study was divided into a first and second therapy period. A total of 38 patients with atrial or ventricular arrhythmias were included in the first therapy period. After a drug-free period of approximately two months, 14 of the 38 patients entered the second therapy period and were given oral sotalol. During the two treatment periods, oral sotalol was given in doses ranging from 40 to 480 mg/day for 0.5 to 11 months in the first period and for four to nine months in the second period. Oral sotalol decreased or abolished arrhythmias in 92 per cent of the patients in the first therapy period and in all the patients in the second therapy period. Minor side effects occurred in two patients. Sotalol possesses a unique class III antiarrhythmic action. The electrophysiological profile is different from other beta-adrenergic blocking agents in that sotalol prolongs the duration of the intracellularly recorded action potential. This property may contribute to the antiarrhythmic efficacy demonstrated with sotalol.