Comparison of the effects of chronic oral therapy with atenolol and sotalol on ventricular monophasic action potential duration and effective refractory period.

The effects of 4 weeks' therapy with atenolol, 50 mg twice daily, and sotalol, 160 mg twice daily, on ventricular monophasic action potential duration (MAPD90) and effective refractory period (VERP) are compared in a randomized cross-over study in 10 patients with stable angina pectoris undergoing elective cardiac catheterization. At matched ventricular pacing cycle lengths (range 500 to 1000 msec), MAPD90 was 29 to 42 msec (11.5% to 13.4%) longer and VERP was 21 to 32 msec (8.9% to 11.4%) longer on oral sotalol than on oral atenolol. Intravenous sotalol (100 mg) caused a significant lengthening of MAPD90 and VERP during oral atenolol therapy, while intravenous atenolol (10 mg) had no additional effect during oral sotalol therapy. The effects of sotalol on ventricular repolarization and refractory period persist over and above any adaptational response to beta-receptor blockade that may occur during chronic therapy.

RCT Entities:   Population Interventions Outcomes