BACKGROUND: There is only a small amount of data available concerning transient exercise-induced ischemia can be detected by the measurement of changes in B-type natriuretic peptides (BNPs). The purpose of this study was to examine the effect of exercise-induced ischemia on levels of N-terminal fragment (NT-pro-BNP) and also to determine whether measurement of these peptides can improve the diagnostic accuracy of exercise testing in stable angina. METHODS: 89 patients with symptoms suggestive of coronary artery disease(CAD) who were referred to our institution for further evaluation were prospectively included. Patients with acute coronary syndromes, impaired LV systolic function, significant valvular heart diseases are excluded. All patients underwent exercise testing and coronary angiography, and 55 patients received Technetium-99m sestamibi single-photon emission computed tomography(SPECT) myocardial scintigraphy. NT-proBNP was analyzed at rest and 20 minutes after exercise testing. RESULTS: Pre NT-proBNP and ∆ NT-proBNP was higher in patients with significant CAD (165.1짹 235.1 vs. 69.2 짹 74.4; 29.3짹 60.8 vs. 6.4 짹 17.1 pg/mL; p < 0.01). Pre NT-proBNP had a tendency to elevation linked to the extent of CAD (no CAD, 69.2 짹 74.4 pg/mL; 1- or 2-vessel disease, 160.2 짹 231.5 pg/mL; 3-vessel disease 173.6짹 262.9 pg/mL; P=NS). ∆ NT-proBNP also had only tendency to elevation linked to the extent of CAD. ∆NT-proBNP had a correlation with the presence of CAD (p<0.05) The area under the curve of the receiver operating characteristic curve was 0.64 for ∆ NT-proBNP to predict CAD. Using an optimized cut off level of 16 pg/mL, CAD can be predicted with high accuracy. However, in a multivariate analysis, ∆NT-proBNP was not an independent predictor for CAD and only predicted by baseline diastolic function. CONCLUSIONS: NT-proBNP is elevated at rest and response to exercise in stable angina. Combining the measurement of NT-proBNP with exercise testing, the test accuracy for predicting CAD could be improved. But, our data suggests the diagnositic value of NT-proBNP should be primarily ascribed to diastolic dysfunction, at least, in stable angina.