Correlation between exercise electrocardiography test and coronary flow reserve in patients without organic coronary artery stenosis.

OBJECTIVES

The exercise electrocardiography (ECG) test is frequently positive in patients without organic coronary artery stenosis. Although the reason for this false positive ST depression is not fully understood, one possibility may be related to coronary microvascular abnormality. The present study investigated the relationship between the exercise ECG test and coronary flow reserve (CFR) in patients with angiographically normal coronary arteries, but with positive ECG ST depression.

METHODS

This study included 67 patients, 32 with chest pain syndrome, and 35 with vasospasm. The exercise ECG test was performed without drug administration in all patients, and the CFR was determined after diagnostic cardiac catheterization.

RESULTS

Although a significant correlation was recognized between ST depression and CFR in patients with chest pain syndrome (p < 0.05), there was no correlation in patients with epicardial coronary vasospasm.

CONCLUSIONS

In patients with chest pain syndrome, ST depression detected by the exercise ECG test may suggest coronary microvascular dysfunction. However, in patients with coronary vasospasm, ST depression may occur without decreased CFR, suggesting that coronary spasm or other mechanism (s) relating to ST changes are present during the exercise ECG test, and careful interpretation is needed.