DOBUTAMINE-INDUCED ST-SEGMENT ELEVATION IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION AND THE ROLE OF MYOCARDIAL-ISCHEMIA, VIABILITY, AND VENTRICULAR DYSSYNERGY

We analyzed the relation between dobutamine-induced Q-wave ST-segment elevation and regional contraction during low (5 to 10 mu g/kg/min) an d high doses (20 to 40 mu g/kg/min) of dobutomine in a series of 391 d obutamine echocardiographic tests performed 10 +/- 2 days after a firs t uncomplicated acute myocardial infarction (AMI). ST-segment elevatio n was defined as greater than or equal to 1 mm new or additional J-poi nt elevation with a horizontal or upsloping ST segment lasting 80 ms. Wall motion score index at rest was derived using a 16 segment-4 grade score model. Patients with dobutamine-induced ST-segment elevation ha d a higher wall motion score index at rest (anterior wall AMI: 1.67 +/ - 0.27 vs 1.43 +/- 0.30, p = 0.0001; inferior wall AMI: 1.44 +/- 0.27 vs 1.30 +/- 0.18, p = 0.0001) and similar incidence and extent of myoc ardial viability and homozonal ischemia in comparison with those witho ut ST-segment elevation. The sensitivity, specificity, and accuracy of dobutamine-induced ST-segment elevation for detecting residual homozo nal ischemia were 51%, 55%, and 54%, respectively, in patients with an terior wall AMI, and 42%, 68%, and 58%, respectively, in patients with inferior wall AMI. In conclusion, dobutamine-induced ST-segment eleva tion is not associated with higher incidence and extent of viable or j eopardized myocardium but rather to a greater extent of wall motion ab normalities at rest. Thus, this finding does not represent a clinicall y reliable discriminator for selecting patients for coronary angiograp hy and possible revascularization procedures. (C) 1997 by Excerpta Med ica, Inc.