BACKGROUND We sought to explore the value of stress-induced transient ischemic dilation (TID) of the left ventricle during dobutamine stress echocardiography, to predict the presence of multi-vessel coronary artery disease as seen by coronary angiography. METHODS We enrolled 60 patients referred to our stress echocardiography labs with ischemic-type chest pain or other symptoms suggestive of myocardial ischemia. All patients underwent resting and stress echocardiography employing the standard dobutamine stress protocol. TID ratio was defined as the ratio of left ventricular end-diastolic volume or end-systolic volume measured at peak stress, to that measured at rest (EDV ratio and ESV ratio, respectively). We enrolled 20 consecutive patients with normal response (control group) who were subsequently evaluated to develop normal limits for TID ratio, and 40 patients with ischemic response (study group) that comprised 20 consecutive patients without TID (group A) and 20 consecutive patients with TID (group B). Patients then underwent coronary angiography. RESULTS Both EDV ratio and ESV ratio were significantly higher in groups A and B as compared to the control group (P<0.01 for both). Analysis of the receiver operating characteristic (ROC) curves identified the 1.12 cutoff value as the optimal cutoff value of TID ratio that best predicts three-vessel disease. Using this cutoff value, the ESV ratio was able to predict three-vessel disease with a sensitivity of 90%, specificity 84%, positive and negative predictive values of 85% and 89%, respectively. The mean number of vessels affected by significant stenosis was 1.8+/-0.83 in group A in comparison with 2.45+/-0.69 in group B (P<0.05). Among group B, both EDV ratio and ESV ratio were higher in female patients as compared to male ones. CONCLUSIONS In patients undergoing dobutamine stress echocardiography, the occurrence of TID is both sensitive and specific to predict underlying three-vessel coronary artery disease.