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 improvement of regional left ventricular function in patients after acute myocardial infarction, and to evaluate the role of low-dose dobutamine stress echocardiography for its prediction. In 57 patients with a first 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 viability was considered if there was an improvement of greater than or equal to 1 Sade In dyssynergic segments from rest to low-dose dobutamine infusion; recovery of regional function was defined as an improvement of greater than or equal to 1 grade between rest and follow up echocardiograms. Wail motion score index decreased from rest to low-dose dobutamine 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 differences were found between patients who did and did not undergo thrombolyis, or between those who had Q-wave and non-Q-wave infarction. At baseline echocardiography, 189 of 627 segments were dyssynergic (85 hypokinetic, 104 akinetic). Viability at low dose dobutamine stress echocardiography was more frequent In hypokinetic than in akinetic segments (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 predictive values of low dose dobutamine stress echocardiography for predicting late recovery of regional function were 66%, 94%, 79%, and 88%, respectively. Sensitivity was tower in akinetic segments than in hypokinetic 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 strong predictor of reversible postischemic dysfunction (odds ratio 17.1, CI 3.5 to 97.1). In conclusion, in patients after a first, relatively uncomplicated acute myocardial infarction, late spontaneous recovery occurs in 26% of the dyssynergic segments. Low-dose dobutamine stress echocardiography provides very specific information for predicting lack of improvement and has a high sensitivity for predicting improvement in hypokinetic segments, but is not useful in identifying akinetic segments that will spontaneously improve.