Relationship between T-wave normalization on exercise ECG and myocardial functional recovery in patients with acute myocardial infarction

Kim, Kyung Jin; Shim, Wan Joo; Jung, Seong Won; Pak, Hui Nam; Lee, Soo Jin; Song, Woo Hyuk; Kim, Young Hoon; Seo, Hong Seog; Oh, Dong Joo; Ro, Young Moo

Abstract

BACKGROUND: Several studies suggested that T-wave normalization (TWN) in exercise ECG indicates the presence of viable myocardium. But the clinical implication of this phenomenon in patients with acute myocardial infarction who received proper revascularization therapy was not determined. Precisely the aim of this study was to investigate the relationship between TWN in exercise ECG and myocardial functional recovery after acute myocardial infarction.
METHODS
We studied 30 acute myocardial infarction patients with negative T waves in infarct related electrocardiographic leads and who had received successful revascularization therapy. Exercise ECG was performed 10 ~14days after infarct onset using Naughton protocol. Patients were divided into 2 groups according to presence (group I; n=14) or not (group II; n=16) of TWN in exercise ECG. Exercise parameters and coronary angiographic findings were compared between groups. Baseline and follow-up (mean 11 months) regional and global left ventricular function was analyzed by echocardiography.
RESULTS
Exercise parameters were similar between groups. There was no difference in baseline ejection fraction and wall motion score between group I and II (EF; 56 +/- 12% vs 52 +/- 11%, p=ns. WMS; 21 +/- 3 vs 23 +/- 4, p=ns) and it was improved at the tenth month by similar magnitude (group I/group II, EF % change = 12 +/- 12% vs 7 +/- 6%, p=ns, WMS % change=6 +/- 6% vs 7+/- 5%, p=ns). The finding of no relation between TWN and functional recovery was observed also when the patients were analysed according to infarct location and presence or absence of Q-waves.
CONCLUSION
As the exercise-induced TWN in patients with acute myocardial infarction was not related with better functional recovery of dysfunctional regional wall motion and ejection fraction, TWN does not appear to be an indicator of myocardial viability.