Background: Most studies concerning exercise electrocardiography (ECG) test
ing after acute myocardial infarction (AMI) were carried out in the prethro
mbolytic era. ST-segment elevation in the infarction area during exercise h
as usually been interpreted as indicating the presence of dyskinesia as a r
esult of extensive left ventricle damage.
Hypothesis: This study was undertaken to evaluate the contributions of exer
cise-induced ST-segment elevation and T-wave pseudonormalization to the ass
essment of myocardial viability in patients with thrombolyzed myocardial in
farction (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 a
nd symptom-limited exercise testing before discharge.
Results: Nineteen patients showed ST-segment elevation (Group 1), 9 showed
isolated T-wave pseudonormalization (Group 2), and 24 patients did not exhi
bit either of these ST-T segment changes (Group 3). Low-dose dobutamine ech
ocardiography revealed evidence of viability in 16 patients (84%) in Group
1 (p = 0.01), 5 (56%) in Group 2 (p = NS), and I I patients (46%) in Group
3 (p = NS).
Conclusion: Exercise-induced ST-segment elevation may contribute to the eva
luation of myocardial viability in patients with AMI treated with thromboly
sis. However, in the absence of exercise-induced ST-segment elevation, furt
her noninvasive studies might be indicated to assess myocardial viability.