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 (ΔVA[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 ΔVA(NO) (from 4.7 ± 0.3 to 16.5 ± 1.6 μmol/liter, p < 0.001) in the patient group. The extent of decrease in LER was significantly correlated with the extent of increase in ΔVA(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.