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To assess the presence of viable myocardium salvaged by coronary artery reperfusion, 17 patients with acute anterior myocardial infarction were studied. Each received intravenous thrombolysis within the first 3 h of symptoms and underwent two-dimensional echocardiography before and during dobutamine infusion (10 micrograms/kg per min) 7 +/- 4 days after admission and positron emission tomography 9 +/- 5 days after admission. Echocardiography and positron emission tomography were again performed 9 +/- 7 months later. Six comparable segments specific for the territory of the left anterior descending artery were selected for comparison of the two techniques. Wall thickening was evaluated by using an echocardiographic score index. Segmental perfusion and glucose uptake were measured and normalized to the peak activity. A ratio of glucose uptake to perfusion was calculated for each segment. Concordant interpretation of the two techniques was found in 79% of affected segments for both acute and follow-up studies. Positron emission tomography revealed the presence of viable myocardium in 11 patients (group 1); perfusion was within normal limits in 5 of these (group 1A). Myocardial thickening improved with dobutamine infusion in these five patients, the echocardiographic score index decreasing from 12 +/- 2 at rest to 7.8 +/- 1.3 during dobutamine infusion (p = 0.003). Functional recovery was demonstrated in all five patients (follow-up score index 7.4 +/- 1.7). Six patients exhibited decreased perfusion but an abnormally high glucose to perfusion ratio (group 1B); their score index improved with dobutamine from 14.8 +/- 2.2 to 12 +/- 2.1 (p = 0.05), but late functional recovery was found in only one of the six patients (mean follow-up score index in group 1B 16 +/- 1.7). In the six remaining patients in whom no viable myocardium was detected with positron emission tomography (group 2), the echocardiographic score index did not change with dobutamine (15 +/- 0.9 to 14.7 +/- 0.8, p = NS) and there was no functional recovery (follow-up score index 15.5 +/- 1.0). Echocardiography during dobutamine infusion is a promising method to unmask viable myocardium in acute myocardial infarction. Early recovery of perfusion in the area at risk is associated with a good functional outcome, whereas a high glucose to perfusion ratio indicates jeopardized myocardium that frequently loses viability.

To identify the haemodynamic response to ischaemia induced by dobutamine stress testing, 15 patients with a first acute myocardial infarction underwent right-sided heart catheterization during dobutamine stress cross-sectional echocardiography. Haemodynamic variables and echocardiography were recorded at rest and during dobutamine infusion at each dose from 5 to a maximum of 40 micrograms kg-1 min-1. Ischaemia was diagnosed by cross-sectional echocardiography if asynergy appeared in at least two ventricular segments other than the area of acute myocardial infarction. Ischaemia was absent in six patients (group I) and identified in nine (group II). Response curves for each haemodynamic variable in the two groups were compared by applying Zerbe's method. The response curves were similar in the two groups for heart rate, arterial, right atrial, pulmonary arterial and pulmonary artery wedge pressures. The response curves were significantly different in groups I and II for thermodilution cardiac output, stroke volume and systemic vascular resistance (P less than 0.05). An increase in stroke volume was observed at low dosage of dobutamine in both groups. From low to maximum dose, stroke volume remained unchanged in group I and was significantly decreased in group II. Ischaemia induced by dobutamine stress testing leads to a decrease in stroke volume with no change in pulmonary artery wedge pressure.

The feasibility, safety and usefulness of 2-dimensional echocardiography (2-D echo) during dobutamine infusion for identifying patients with multivessel coronary artery disease (CAD) after acute myocardial infarction (AMI) were evaluated in 30 patients 5 to 10 days after AMI. Patients underwent 2-D echo under basal conditions and during dobutamine infusion at each dose from 5 to a maximum of 40 micrograms/kg/min, limited multilead submaximal bicycle exercise testing and coronary and left ventricular angiography. Echocardiograms were analyzed independently by 2 observers. The test response was considered positive if abnormal wall motion and reduced myocardial thickening were observed during dobutamine infusion in vascular distributions other than the area of infarction identified during basal conditions. Exercise testing was considered positive when more than 1 mm of ST depression occurred 80 ms after the J point. Dobutamine stress testing was well tolerated; no complications and no significant arrhythmia were observed. Echocardiographic recordings were adequate in all patients during the entire test; the concordance in interpretation between the 2 observers was perfect for the prediction and location of ischemic segments during dobutamine infusion. In 15 of 17 patients without multivessel CAD, no asynergy was observed outside the infarct zone during dobutamine infusion (specificity 88%). In 11 of 13 patients with multivessel CAD, new wall motion abnormalities were identified in the segments corresponding to the arterial lesions diagnosed by angiography (sensitivity 85%).(ABSTRACT TRUNCATED AT 250 WORDS)