Prognostic value of 12-lead electrocardiogram during dobutamine stress echocardiography

The aim of this study was to assess the prognostic value of the 12-lead electrocardiogram (ECG) obtained during dobutamine stress echocardiography (DSE) in predicting subsequent cardiac events. We retrospectively analyzed 345 patients undergoing DSE in 1992-1994 and selected those patients with negative echo results for ischemia. Of the 200 patients with negative DSE results, a separate analysis of their ECG data was performed with results reported as either positive, negative, or nondiagnostic for ischemia. Follow-up was performed through a physician chart review and direct telephone contact. Event rates were determined for hard (myocardial infarction or cardiac death) and soft (hospitalization for angina and/or congestive heart failure, coronary angioplasty, or coronary artery bypass graft surgery) cardiac events occurring after the negative DSE for up to 6 years after the test. Death was also determined by referencing the patients' data with mortality data available on the Internet. There were 143 patients with ECG data reported as negative and 40 patients with ECG data reported as positive for ischemia. The hard and soft event rates were 1.5% and 9% per patient per year in the ECG negative group and 2% and 11% in the ECG positive group. There were no statistical differences in event rates between the two groups during the 5-year follow-up period. Our results suggest that the ECG result obtained during DSE does not confer any incremental prognostic value over the echo result.