BACKGROUND:The ratio of mitral inflow early diastolic velocity (E) to annulus velocity (E') might be critical for the assessment of an abnormal filling pressure for patients with myocardial ischemia. OBJECTIVES:We sought to determine whether a quantitative estimation of E/E' provides more reliable information for detecting coronary artery disease during dobutamine stress echocardiography. METHODS:A total of 82 patients suggested to have angina pectoris underwent Doppler studies during dobutamine stress echocardiography. The value of E and E' were measured at baseline and peak dose of dobutamine stress. The value of E/E' during stress over that at rest was defined as the E/E' index. RESULTS:Patients who had significant stenosis by coronary angiogram were classified as being in group A (n = 45) and those with no coronary artery disease were classified as being in group B (n = 37). Dobutamine infusion led to a significant increase of E/E' in group A, whereas no changes were found with group B. Likewise, larger E/E' index was also observed for patients with multivessel disease. The value of E/E' index increased proportionally with the number of stenotic vessels, implying a direct correlation of the E/E' value to the extent of myocardial ischemia. CONCLUSIONS:E/E' offers a quantitative estimation of myocardial ischemia during dobutamine stress echocardiography, thereby, providing a reliable and accurate method for the evaluation of coronary artery disease.