Exercise tolerance in patients with angina pectoris after pentaerythritol trinitrate and alprenolol studied by two different methods
Exercise tolerance has been studied by two different methods, heart-rate-controlled exercise and stepwise increased load, in 12 patients with angina pectoris. The response to a beta-adrenergic blocking agent, alprenolol, and an alkyl nitrate derivative, pentaerythritol trinitrate (PETRIN) was studied by the two methods after double-blind administration of the drugs. Rating scales were used to quantitate the degree of dyspnoea, angina pectoris and tiredness in the legs. After PETRIN both methods showed significant increases in exercise tolerance (19 and 21 per cent). The heart-rate-controlled test showed a significant increase (33%) after alprenolol, but the change was not significant by the other method. In the patients studied, heart-rate-controlled exercise discriminated between active drug and placebo better than the stepwise increased load test, what might have been due to more optimal matching of the loads obtained in the heart-rate-controlled test. Indications are given about how to design an exercise study in patients with angina pectoris.