Increased release of nitric oxide in ischemic hearts after exercise in patients with effort angina.

OBJECTIVES The aim of this study was to determine whether the release of nitric oxide (NO) from the ischemic heart increases during exercise in patients with effort angina. BACKGROUND Myocardial ischemia increases NO production in the canine heart, but no such increase has been demonstrated in the ischemic human heart. METHODS Fifteen patients with effort angina underwent supine ergometer exercise tests. All patients had severe proximal stenosis (>90%) in the left anterior descending coronary artery. The control group consisted of 17 subjects without coronary artery disease or systemic hemodynamic abnormalities. RESULTS Neither the lactate extraction ratio (LER) nor the difference in NO concentration between coronary venous and arterial blood (deltaVA[NO]) was affected by exercise in the control subjects. In patients with effort angina, neither variable differed from that in the control group at rest; however, exercise markedly decreased LER and significantly increased deltaVA(NO) (from 4.7 +/- 0.3 to 16.5 +/- 1.6 micromol/liter, p < 0.001) in the patient group. The extent of decrease in LER was significantly correlated with the extent of increase in deltaVA(NO) in the patients with effort angina (r2 = -0.837, p < 0.001). CONCLUSIONS Provocation of myocardial ischemia by exercise stress increases NO production in the hearts of patients with effort angina.