Abstract: Objective: To study whether the value of QT interval dispersion(QTd) increases along with precipitation of myocardial ischemia in transesophagus atrial pacing heart stress test.Methods: The QTd was measured in patients with coronary artery disease and normal subjects before stress test,during stress test,when the pacing heart rate achieved the maximum,the moment and two minutes after stress test.Results: QTd of the maximal pacing heart rate during stress test,the moment and two minutes after stress test increased significantly(P<0.01) compared with those before stress test in patients with cornary artery disease.QTd of the maximal pacing heart rate during stress test,the moment and two minutes after stress test did not increase significantly(P>0.05) compared with those before stress test in normal subjects.Conclusions: It suggests that increase of QTd might be used as an index to judge coronary artery disease in transesophagus atrial pacing heart stress test.