Significance of T-wave changes during early dobutamine stress echocardiography in patients with Q-wave acute myocardial infarction

The relation between T-wave changes and regional contraction during dobutam ine;stress echocardiography at low (5 to 10 mu g/kg/min) and high (20 to 40 mu g/kg/ min) doses in 43 consecutive patients, early (7 +/- 2 days) after first recent Q-wave acute myocardial infarction has been evaluated. T-wave changes detected in greater than or equal to 2 infarct-related electrocard iographic leads during dobutamine infusion were defined as follow: (1) nega tive T waves becoming positive, (2) positive T waves becoming upright great er than or equal to 2 mm, and (3) negative T waves becoming upright greater than or equal to 2 mm from baseline. Wall motion score index (WMSI) was de fined as the sum of the echocardiographic scores of 16 segments divided by total segments considered at baseline, and at low and peak doses of dobutam ine. Patients were classified according to the absence or presence of dobut amine T-wave changes. Those without T-wave changes had a significantly high er WMSI at rest (1.68 +/- 0.23 vs 1.50 +/- 0.21; p <0.05) and at peak (1.77 +/- 0.34 vs 1.51 +/- 0.30 p <0.05) of dobutamine stress testing, without h igher incidence of viability, homozonal, and heterozonal ischemia and chest pain. The angiographic patterns were similar between groups. Regression an alysis showed a significant correlation between WMSI and T-wave amplitude a t baseline (R = 0.38, p = 0.01) and at peak dobutamine stress testing (R = 0.50, p = 0.0006). The sensitivity sensitivity, specificity, and accuracy o f T-wave changes to detect myocardial viability were 0.27, 0.84, and 0.70, respectively. The sensitivity, specificity, and accuracy of T-wave changes to detect homozonal ischemia were 0.76, 0.27, and 0.46, respectively. In co nclusion, dobutamine-induced T-wave changes are associated with a greater e xtent of wall motion abnormalities both at rest and at peak stress echocard iography, but they are of little value in predicting myocardial viability w hen analyzed early after myocardial infarction. (C) 1999 by Excerpta Medico , Inc.