Background: Exercise electrocardiography (ECG) has high specificity but limited sensitivity for the detection of myocardial ischemia. The aim of this study was to determine whether measurement of B-type natriuretic peptide (BNP) can improve the diagnostic accuracy of exercise ECG.
Methods: A total of 256 consecutive patients with suspected myocardial ischemia referred for rest/ergometry myocardial perfusion single-photon emission computed tomography were enrolled. Levels of BNP were determined before and 1 minute after maximal exercise.
Result: Inducible myocardial ischemia on perfusion images was detected in 127 patients (49.6%). Median BNP levels at rest and after peak exercise were higher in patients with than without inducible ischemia (71 pg/mL vs 38 pg/mL, P < .001; and 88 vs 52 pg/mL, P < .001, respectively). Compared with patients in the lowest peak exercise BNP quartile, those in the highest quartile of peak exercise BNP had more than 3 times the risk of inducible ischemia (adjusted relative risk 3.3, 95% CI 1.3-8.6, P = .015). Using 110 pg/mL as a cutoff, the combination of exercise ECG and peak exercise BNP level distinguished between ischemic and nonischemic patients more accurately than the exercise ECG alone (67% vs 60%, P = .024). Although the increase in accuracy was similar for the combination of exercise ECG with baseline BNP or DeltaBNP, overall, peak exercise BNP seemed to be the preferred measurement.
Conclusions: B-type natriuretic peptide levels are associated with inducible myocardial ischemia. The use of BNP levels improves the diagnostic accuracy of exercise ECG.