Myocardial viability in patients with thrombolyzed myocardial infarction: Is it assessable by predischarge exercise electrocardiography test?

Abstract

Background: Most studies concerning exercise electrocardiography (ECG) testing after acute myocardial infarction (AMI) were carried out in the prethrombolytic era. ST‐segment elevation in the infarction area during exercise has usually been interpreted as indicating the presence of dyskinesia as a result of extensive left ventricle damage. Hypothesis: This study was undertaken to evaluate the contributions of exercise‐induced ST‐segment elevation and T‐wave pseudonormalization to the assessment of myocardial viability in patients with thrombolyzed myocardial infarction (MI), compared with low‐dose dobutamine echocardiography. Methods: The study comprised 52 consecutive patients with AMI treated with thrombolysis. All patients underwent low‐dose dobutamine echocardiography and symptom‐limited exercise testing before discharge. Nineteen patients showed ST‐segment elevation (Group 1), 9 showed isolated T‐wave pseudonormalization (Group 2), and 24 patients did not exhibit either of these ST‐T segment changes (Group 3). Low‐dose dobutamine echocardiography revealed evidence of viability in 16 patients (84%) in Group 1 (p=0.01), 5 (56%) in Group 2 (p=NS), and 11 patients (46%) in Group 3 (p = NS). Conclusion: Exercise‐induced ST‐segment elevation may contribute to the evaluation of myocardial viability in patients with AMI treated with thrombolysis. However, in the absence of exercise‐induced ST‐segment elevation, further noninvasive studies might be indicated to assess myocardial viability.