[Effect of metoprolol on the exercise tolerance in patients with stable angina pectoris (author's transl)]

The effect on the exercise tolerance induced by a new selective beta1-receptor antagonist, metoprolol, given by a single administration per os, has been evaluated in 16 patients with stable angina pectoris. The study was a double blind cross-over between metoprolol 100 mg and placebo. Patients were hospitalized for the time required for the performance of the study; every cardioactive drug, except for trinitrine, was stopped 72 hours prior to the study period. Exercise testing was performed two hours after the intake of the drug, in a sitting position on a bicycle ergometer; the workload was increased by 25 Watts increments every two minutes. Compared to placebo, the total workload performed and duration of exercise increased after metoprolol (P less than 0.001), heart rate decreased (P less than 0.001) both in the resting state and during exercise test, systolic blood pressure didn't change in the resting state but decreased during exercise test (P less than 0.01), pressure-rate product, an useful index of changes in myocardial oxygen consumption decreased both in the resting state (P less than 0.001) and during exercise test (P less than 0.001). It is concluded that metoprolol induces a significant increase in exercise tolerance. This is due to a marked reduction in oxygen myocardial consumption resulting by both decreased heart rate and systolic pressure.