Abstract: To investigate the relationship between myocardial ischemia during adenosine stress testing and the changes in left ventricular ejection fraction (LVEF) measurements after stress and rest geted myocardial perfusion imaging. 104 patients suspecting myocardial ischemia underwent adenosine stress-rest protocol and gated single photon emission computed tomography (SPECT). Perfusion analysis was performed with a 17-segment model. Myocardial ischemia were assessed with 5-point scale. Summed stress score(SSS), summed rest score(SRS) and summed difference score(SDS=SSS-SRS) were calcurated. An SSS score exceeding 3 points was considered positive for coronary artery disease, and SDS greater than 2 indicated resersiable ischemia. Resting and poststress LVEFs correlated significantly, and there was no significant difference between stress and rest（t=-0.655，P＞0.05）. However, patients with reversible ischemia had significant differences in poststress versus resting LVEF, EDV and ESV. In patients with stress-induced perfusion ischemia, the LVEF after stress was significantly lower than the rest. LVEF descending in adenosine imaging indicated myocardial ischemia.