Effect of atenolol on treadmill performance in patients with angina pectoris.

The efficacy and safety of atenolol was evaluated in 16 patients with exertional angina pectoris in a single-blind, once daily, increasing dose study. All patients had coronary artery disease documented by previous myocardial infarction, coronary angiography, or an abnormal exercise ECG. After a four-week placebo period, patients received 25, 50, and 100 mg of atenolol once daily during three two-week periods. This was followed by a three-week treatment period with 200 mg of atenolol once daily. The study was concluded with a two to four week posttreatment period. Antianginal efficacy was assessed by monitoring changes in treadmill exercise performance in each patient 3 and 24 hours after the administration of atenolol. The endpoint of the treadmill exercise was mild but definite chest pain. At 3 and 24 hours after all dosages, atenolol significantly prolonged the duration of exercise and increased the work performed. The pulse rate and double product at the endpoint of exercise were lower with all atenolol doses. Overall, at 24 hours after the administration of atenolol, exercise tolerance was progressively increased as the dose increased. The mean duration of exercise and work performed increased 28.5 and 35.4%, respectively, on the 25-mg dose; 36.9 and 45.5%, respectively, on the 50-mg dose; 45.1 and 59.5%, respectively, on the 100-mg dose; and 65.4 and 84.8%, respectively, on the 200-mg dose. Patient acceptance and compliance were good. Single daily doses of atenolol constitute effective therapy for exercise-induced angina.