DOBUTAMINE STRESS ECHOCARDIOGRAPHY PREDICTS REVERSIBLE DYSFUNCTION AND QUANTITATES THE EXTENT OF IRREVERSIBLY DAMAGED MYOCARDIUM AFTER REPERFUSION OF ANTERIOR MYOCARDIAL-INFARCTION

Objectives. This study was designed to evaluate dobutamine stress echo cardiography in identifying reversible dysfunction and assessing the e xtent of irreversibly damaged myocardium early in acute myocardial inf arction. Background. Several experimental and clinical studies have su ggested that dobutamine enhances contractile function of stunned or hi bernating, or both, myocardium. It is important for clinical strategy to predict the magnitude of improvement in myocardial function early i n acute myocardial infarction. Methods. We studied 21 patients with a reperfused first anterior myocardial infarction. Two-dimensional echoc ardiography was performed before and during dobutamine infusion (10 mu g/kg body weight per min) at a mean of 3 days after the infarction. F ollow-up echocardiography was performed at a mean of 25 days later. To assess segmental wall motion, we divided the left ventricle into 17 s egments and assigned a wall motion abnormality score: 3 = dyskinesia o r akinesia; 0 = normal. Improvement in wall motion was indicated by a decrease of at least one grade in segmental score. For quantitative as sessment, the ratio of endocardial length showing dyskinesia or akines ia to a left ventricular endocardial length (akinetic length ratio) wa s determined in the apical long-axis view at each stage. Results. Sens itivity and specificity of dobutamine infusion in detecting improvemen t in wall motion at follow up echocardiography were 83% (55 of 66 segm ents) and 86% (43 of 50 segments), respectively. Excellent correlation was found (r = 0.93, p < 0.001; absolute difference [mean +/- SD] 0.0 3 +/- 0.05) between the akinetic length ratios measured during dobutam ine infusion and in the late convalescent stage. Conclusions. In the e arly stage of acute myocardial infarction, low dose dobutamine stress echocardiography provides a useful method for predicting reversible dy sfunction with excellent sensitivity and specificity and can also be u sed to quantitate the extent of irreversibly damaged myocardium.