Improved myocardial performance during repetitive exercise testing: the role of extracellular superoxide dismutase activity in a model of exercise-induced myocardial preconditioning.

Background: The aim of this study was to investigate whether endogenous antioxidant defense is involved in adaptation to myocardial ischemia in patients with coronary artery disease and severe exercise-induced myocardial ischemia.

Methods: Fifty patients, aged 50 to 72 years (mean, 58 +/- 6 years), with positive exercise test results underwent 4 treadmill exercise tests. Thallium-201 scintigraphy was performed during the first and the fourth testing.