This study was performed to evaluate whether dobutamine stress echocardiography (DSE) can provide any additional information regarding the location and severity of coronary artery disease (CAD) in an individual patient. DSE was performed in 233 patients with clinical manifestations of angina pectoris. There were 162 patients with angiographically documented CAD defined as > or = 50% diameter stenosis. The severity of coronary lesions was divided into three groups: 50-75, 76-90 and >90%. The diagnostic sensitivity in detecting left anterior descending artery (LAD) and right coronary artery (RCA) lesions was higher for lesion severity of>90% than of 50-75% (p = 0.01 for LAD and p < 0.05 for RCA). The diagnostic sensitivity in detecting CAD was highest among patients with proximal coronary lesions (89% for LAD, 64% for the left circumflex artery, and 81 % for the RCA). When lesion severity increased from 50-75 to >90%, wall motion scores at peak dose during dobutamine infusion increased from 12.3 +/- 4.3 to 18.4 +/- 5.4 (p = 0.003) in the proximal LAD lesion group and from 10.6 +/- 2.0 to 20.4 +/- 5.9 (p < 0.0001) in the mid-distal LAD lesion group. When lesion severity increased from 50-75 to >90%, wall motion scores at peak dose increased from 5.9 +/- 2.0 to 8.0 +/- 2.5 (p < 0.05) in the proximal RCA lesion group and from 5.2 +/- 2.1 to 8.1 +/- 1.9 (p < 0.05) in the mid RCA lesion group. However, the change in wall motion scores did not reach statistical significance in proximal and distal lesions of the left circumflex artery when lesion severity increased from 50-75 to >90%. The correlation coefficient between quantitative wall motion score and Gensini's score was 0.54 (p = 0.0001) in all patients and 0.6 (p = 0.0001) in patients without myocardial infarction. In conlcusion, the functional significance of lesion severity and distribution can be evaluated by DSE. Regional dyssynergy of LAD and RCA territories during peak-dose dobutamine infusion was most apparent at the stenotic level >90%.