Sustained effect of nitroglycerin ointment on exercise tolerance in patients with effort angina

The effect on exercise tolerance of nitroglycerin (NTG) ointment was studied by exercise test on bicycle ergometer in a selected group of patients with effort angina and angiographically proven critical coronary lesions. NTG ointment (15 mg) and placebo were administered in a double-blind cross-over randomized trial on two consecutive days; exercise test was carried out before the administration of NTG ointment and placebo, and repeated after one hour, 2 and 1/2 hours and 4 hours. Compared to control and placebo tests, NTG ointment produced a highly significant increase of duration of exercise and of total work load in all tests, as well as a significant decrease of maximal ST segment depression. After NTG ointment administration resting systolic blood pressure showed a significant decrease after one hour, 2 and 1/2 hours and 4 hours, resting heart rate a significant increase after 2 and 1/2 and 4 hours, and peak exercise heart rate a significant increase after 4 hours. Double product at rest was unaffected by NTG ointment, while at peak exercise it showed a significant increase only after 4 hours. Our data show that in patients with effort angina NTG ointment produces an important increase of exercise capacity which persists at least for 4 hours after the administration. Therefore NTG ointment seems to be of high value in the treatment of effort angina.