Different effects of acute administration of aminophylline and nitroglycerin on exercise capacity in patients with syndrome X

Abstract

To investigate the effects of the acute administration of aminophylline and nitroglycerin on effort ischemia, 20 patients with syndrome X underwent 3 bicycle exercise tests after sublingual nitroglycerin (0.3 mg) and after 90 minutes of oral administration of aminophylline (400 mg). Compared with the basal test, only aminophylline induced a significant increase in the time to ischemic threshold and to angina; these findings support the potential therapeutic role of this adenosine receptor blocking agents and suggest a possible role of "steal phenomenon" in the pathogenesis of effort angina in patients with syndrome X.