PREDICTION OF IMPROVEMENT OF VENTRICULAR-FUNCTION AFTER FIRST ACUTE MYOCARDIAL-INFARCTION USING LOW-DOSE DOBUTAMINE STRESS ECHOCARDIOGRAPHY

This study was performed to assess the prevalence of spontaneous impro vement of regional left ventricular function in patients after acute m yocardial infarction, and to evaluate the role of low-dose dobutamine stress echocardiography for its prediction. In 57 patients with a firs t acute myocardial infarction (thrombolysis, n = 27; Q-wave, n = 49), regional wall motion was evaluated with 2-dimensional echocardiography at rest, during a low-dose dobutamine stress test performed within 1 week after hospital admission, and at 3-month follow-up. Myocardial vi ability was considered if there was an improvement of greater than or equal to 1 Sade In dyssynergic segments from rest to low-dose dobutami ne infusion; recovery of regional function was defined as an improveme nt of greater than or equal to 1 grade between rest and follow up echo cardiograms. Wail motion score index decreased from rest to low-dose d obutamine echocardiography (1.46 +/- 0.29 to 1.39 +/- 0.30, p <0.0001) , and this change persisted at follow-up study (1.37 +/- 0.30). No dif ferences were found between patients who did and did not undergo throm bolyis, or between those who had Q-wave and non-Q-wave infarction. At baseline echocardiography, 189 of 627 segments were dyssynergic (85 hy pokinetic, 104 akinetic). Viability at low dose dobutamine stress echo cardiography was more frequent In hypokinetic than in akinetic segment s (30 of 85 vs 12 of 104, odds ratio 4.18, 95% confidence interval [CI ] 1.87 to 9.48). Spontaneous recovery was more frequent in hypokinetic than in akinetic segments (30 of 85 vs 20 of 104, odds ratio 2.29, CI 1.13 to 4.68). Sensitivity, specificity, and positive and negative pr edictive values of low dose dobutamine stress echocardiography for pre dicting late recovery of regional function were 66%, 94%, 79%, and 88% , respectively. Sensitivity was tower in akinetic segments than in hyp okinetic segments (35%, CI 0.14 to 0.56, vs 87%, CI 0.75 to 0.99). An improvement during low-dose dobutamine stress echocardiography was a s trong predictor of reversible postischemic dysfunction (odds ratio 17. 1, CI 3.5 to 97.1). In conclusion, in patients after a first, relative ly uncomplicated acute myocardial infarction, late spontaneous recover y occurs in 26% of the dyssynergic segments. Low-dose dobutamine stres s echocardiography provides very specific information for predicting l ack of improvement and has a high sensitivity for predicting improveme nt in hypokinetic segments, but is not useful in identifying akinetic segments that will spontaneously improve.