[Effect of atenolol and nitroglycerin ointment on exertion tolerance in coronary disease]

In a randomized, placebo-controlled double-blind cross-over study the effect and duration of effect of 2% nitroglycerin ointment (2 cm/m2 body surface) and 50 mg atenolol, as the only drug or the two in combination, were tested on 16 patients with coronary heart disease. Heart rate at rest and on exercise rose significantly for up to 3 1/2 hours (P less than 0.01) after application of the nitroglycerin ointment. Systolic blood pressure at rest and five minutes after exercise was significantly reduced (P less than 0.01), while on exercise there was no significant difference from the control value. Pressure X heart rate product was significantly raised over the initial value up to 3 1/2 hours after application, at maximal exercise (P less than 0.05), while after atenolol there was a highly significant reduction compared with the placebo (P less than 0.01), even after six hours. S-T depression was reduced at maximal comparable exercise level by 49% after atenolol, 52% after nitroglycerin ointment and 76% after combination of the two (P less than 0.05). Exercise tolerance was on average increased for 1 1/2 hours after atenolol by 36%, after nitroglycerin ointment by 58% and after the combined application by 84%, compared with the placebo (P less than 0.01). In the latter (combination) group the pressure X heart rate product was definitely below that of the nitroglycerin ointment group. Thus additional administration of 50 mg atenolol can decrease the pressure X heart rate product after application of nitroglycerin ointment, at the same time increasing exercise tolerance and reducing the degree of S-T depression.