T wave alternans in experimental myocardial infarction: Time course and predictive value for the assessment of myocardial damage

Background: T-wave alternans (TWA) is associated with prognosis after myocardial infarction (MI), however its link to the extent of ischemic injury has not been clarified. We analyzed the course of TWA and its relation to myocardial damage in experimental myocardial infarction. Methods: In 21 pigs, infarction was induced by 40-minute long balloon inflation in LAD under continuous 12-lead ECG monitoring. TWA was assessed in a 32-beat sliding window, using periodic component analysis and the Laplacian Likelihood Ratio method. Myocardium at risk (MaR) and infarct size (IS) were evaluated by SPECT and magnetic resonance imaging respectively. Results: TWA appeared at 7.2 +/- 4.5 minutes of occlusion, reached its maximum at 12.7 +/- 6.3 and lasted until 26.5 +/- 9.2 minutes. The maximal level of TWA was associated with both MaR (r = 0.499, p = 0.035) and IS (r = 0.65, p = 0.004). Conclusion: TWA magnitude is associated with both MaR and IS in experiment, which encourages further studies in clinical settings. (C) 2013 Elsevier Inc. All rights reserved.