Brain natriuretic peptide (BNP) levels were measured in 100 patients with coronary heart disease (CHD) who underwent myocardial stress thallium-201 single-photon emission computed tomography (30 with stable angina without basal electrocardiographic ischemia and no perfusion defects, 31 with angina with electrocardiographic ischemia and reversible perfusion defects, and 39 with myocardial infarction and irreversible defects) and in 42 controls. BNP levels progressively increased in patients with CHD and were significantly greater in patients with ischemia (p <0.01) and infarction (p <0.001) compared with controls and subjects with angina. BNP concentration was correlated positively (r = 0.923, p <0.001) with perfusion defect extent and inversely (r = -0.690, p <0.001) with the left ventricle ejection fraction (not different in the subjects examined).