Late phase of repolarization (TpeakTend) as a prognostic marker of left ventricle remodeling in patients with anterior myocardial infarction treated with primary coronary intervention.

BACKGROUND: Left ventricle remodeling (LVR) is regarded as a marker of unfavorable outcome in patients following acute myocardial infarction (AMI). Repolarization, especially its late part (TpeakTend), is strongly related to local myocardial attributes. We assessed prospectively in this study if repolarization duration (measured from one hour of nighttime) might predict LVR occurrence in patients with anterior AMI treated with primary percutaneous coronary intervention (PCI).

METHODS: The study population consisted of 111 patients with first anterior AMI (82 males, age 58 +/- 11 years, LVEF 41 +/- 7%) treated with the primary PCI of left anterior descending coronary artery. LVR, defined as left ventricle end-diastolic volume increase by > 20% during six months follow-up, occurred in 35 patients (31 males, age 56 +/- 10 years, LVEF 37 +/- 7%, LVR+), while the other 76 subjects were free of LVR (51 males, age 58 +/- 10 years, LVEF 43 +/- 7%, LVR-). Holter recordings were performed in the fifth day of AMI. Repolarization parameters: QT, QTpeak and TpeakTend were assessed from one hour of nighttime Holter recording (between 1-4 a.m.).

RESULTS: LVR occurred more frequently in males (p = 0.02). LVEF was lower in LVR+ patients (p = 0.001). QTc was similar: 441 +/- 29 ms vs 434 +/- 25 ms, p = 0.37 for LVR+ vs LVR-. Patients with LVR had shorter QTpeakc (333 +/- 34 ms vs 345 +/- 25 ms, p = 0.03) and remarkably longer TpeakTendc (108 +/- 15 ms vs 89 +/- 17 ms, p = 0.0001). Receiver operating characteristics analysis revealed that the best cut-off value for LVR prediction was 103 ms--sensitivity: 65.7%, specificity: 81.6%, positive predictive value: 62%, negative predictive value: 83.8%.

CONCLUSIONS: The greater transmural heterogeneity of the repolarization processes described by TpeakTend interval measured at discharge after AMI seems to be a prognostic marker of left ventricle remodeling occurrence during six months follow-up in patients with acute anterior infarction.