DOBUTAMINE STRESS ECHOCARDIOGRAPHY EARLY AFTER MYOCARDIAL-INFARCTION TREATED WITH THROMBOLYSIS - IDENTIFICATION OF MYOCARDIAL VIABILITY ANDISCHEMIA AND RELATION TO SPONTANEOUS FUNCTIONAL RECOVERY

The aim of the study was to assess the ability of dobutamine stress ec hocardiography to detect myocardial viability and ischemia in patients with acute myocardial infarction treated with thrombolysis and to cor relate the acute response to dobutamine with late spontaneous function al recovery at follow-up. Forty-two consecutive patients with myocardi al infarction treated with thrombolysis underwent low- (5 and 10 mcg/k g/min) and high-dose (20 to 40 mcg/kg/min) dobutamine stress echocardi ography at a mean of 7 +/- 3 days of the acute phase. A follow-up 2D-e chocardiogram was performed in all patients to evaluate the spontaneou s recovery of function in the infarct area. On the basis of the respon se to the test, 3 groups of patients were identified: group 1 included 7 patients showing an improvement in left ventricular asynergy score index at low doses (from 1.5 +/- 0.3 to 1.3 +/- 0.2, p < 0.05) with no deterioration at high doses, indicative of myocardial viability witho ut ischemia; group 2 (23 patients) showed a significant improvement in the asynergy index at low doses (from 1.58 +/- 0.3 to 1.32 +/- 0.32, p < 0.05) followed by a deterioration at high doses (1.68 +/- 0.4, p < 0.05 vs low-dose), suggestive of residual myocardial ischemia in the infarct zone; group 3 included 12 patients who showed no significant c hanges in the baseline asynergy score index (1.67 +/- 0.2) either at l ow or at high doses. The acute response to dobutamine stress echocardi ography accurately predicted the spontaneous recovery of function in t he infarct area at follow-up: both group 1 and group 2 patients showed a significant reduction in the asynergy score index (group 1: 1.16 +/ - 0.3 vs 1.5 +/- 0.2, p < 0.001; group 2: 1.43 +/- 0.3 vs 1.58 +/- 0.3 , p < 0.05), while group 3 had no recovery in the asynergy index (1.67 +/- 0.2 vs 1.67 +/- 0.2). Thus, in patients with acute myocardial inf arction treated with thrombolysis dobutamine stress echocardiography c an detect myocardial viability in 71% and ischemia in the infarct zone in 55% of patients; moreover, the response to the test during the acu te phase is correlated with the degree of the late spontaneous recover y of function in the infarct area.