Electrocardiographic response during dobutamine stress echocardiography

Studies assessing dobutamine stress (DS) echocardiograpphy (echo) have included 12-lead electrocardiograms (ECG) in their protocol. We retrospectively reviewed the records of 76 patients who were referred for DS echo and coronary angiography to assess the incremental diagnostic value of DS ECG beyond the results of the echocardiographic images of the DS echo. The prevalence of coronary artery disease was 86%. Baseline ST-segment abnormalities prohibited assessment of ischemic ST-segment changes in 35 (46%) patients. For the detection of a ≥50% stenosis on coronary angiography, DS echo alone had a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92%, 73%, 95%, 62%, and 89%, respectively. The DS ECG alone had a sensitivity, specificity, PPV, NPV, and accuracy of 38%, 45%, 81%, 11%, and 39%, respectively. Combined results of the DS echo and the DS ECG slightly increased sensitivity, but with a marked reduction in specificity, PPV, NPV, and accuray. We conclude that (1) DS ECG is interpretable for ischemic ST-segment changes in about 50% of patients referred for DS echo; (2) DS ECG is a poor predictor of coronary artery disease; and (3) DS ECG response only slightly increases the sensitivity of the echo findings of a DS echo study. Because the incremental diagnostic value of the DS ECG response is poor, elimination of the 12-lead DS ECG is unlikely to diminish the diagnostic value of the DS echo and may result in a substantial cost savings.