A comparison of the efficacy of sotalol and nadolol in the suppression of ventricular ectopic beats.

The anti-arrhythmic efficacy of sotalol, a beta-blocking agent which possesses class III anti-arrhythmic properties, was compared with that of nadolol. Nadolol, like sotalol, is non-cardioselective, is water-soluble, has no first-pass effect, is excreted unchanged in the urine, has a comparatively long half-life requiring only once-daily dosage, and has no intrinsic sympathomimetic activity and no membrane-stabilizing action. Twenty-two patients with stable chronic ventricular arrhythmias after myocardial infarction were studied; to qualify for entry they had to exhibit a minimum frequency of 30 ventricular ectopic beats per hour over a 24-hour Holter monitoring period. The study was of single-blind, cross-over format with placebo periods before active drug administration and during the cross-over periods. Nadolol 80 and 160 mg and sotalol 160 and 320 mg were administered for 7-day periods. Routine laboratory tests were performed and serum drug concentrations measured at regular intervals. Both drugs at all dosages suppressed ventricular ectopic beats significantly (P less than 0,001). No statistically significant prolongation of the QTc interval could be demonstrated with either drug. Side-effects were negligible.