Dobutamine Stress Echocardiography(DSE) is widely used as a non-invasive test to screen for the presence of coronary artery disease ICAD). Its ability to accurately separate patients (pts) with limited vessel (0 or 1 vessel) disease (LVD) from high risk multi-vessel 12 or 3) disease (MVD) pts, in the presence of decreased resting left ventricular ejection fraction (LVEF) is unknown. Accordingly, we analyzed the results from 136 consecutive pts who underwent both coronary angiography and DSE. DSE was performed with graded dobutamine infusion of 5,10,20,30, and 40μg/kg/min in 5min stages, and WMA was graded using a 16 myocardial segment model. DSE was considered indicative of MVD when there were at least two abnormal contiguous segments in two different coronary distributions. CAD was considered significant when >50% luminal area narrowing was present. There were 27 pts with O-V, 52 with 1-V, 40 with 2-V, and 17 with 3V CAD. The data from 59 of 136 (42%) pts who had an LVEF ≤40% were compared to the 79 pts with an LVEF >40%: ParametersEF >40% (N=79)EF <40% (N=57)0–1 V2–3 V0–1 V2–3 VSensitivity %70671486Specificity %67708626In pts with LVEF >40% DSE had similar accuracy in identifying LVD and MVD. In contrast. the specificity of DSE in separating LVD from MVD was poor in patients with decreased LVEF. These results suggest that 11) DSE in an adequate screening test for MVD and (2) baseline LVEF contributes importantly to the overall interpretation of DSE in predicting MVD.