Time Variance of Electrocardiographic Transmural Dispersion in Acute Myocardial Infarction

ABSTRACT

BACKGROUND AND OBJECTIVES: The mechanism responsible for lethal ventricular arrhythmia (LVA) after acute myocardial infarction (AMI) remains unclear. SUBJECTS AND METHODS: The corrected QT interval (QTc) and interval from the peak to the end of the T wave (TpTe) were measured, which indicated myocardial transmural dispersion of repolarization (TDR) in 72 patients with AMI. TpTe was also expressed as a corrected value, [TpTe/QTe]x100% and TpTe/√RR. These parameters were obtained from all the 12-leads of electrocardiography after arrival at the hospital, just before and after percutaneous coronary intervention (PCI), and at 4, 24, and 48 hours and 5 days after PCI. RESULTS: Analyzing with repeated measures analysis of variance, the TpTe, [TpTe/QTe]x100% and TpTe/√RR after AMI showed significant changes in time variance. The patients were divided into LVA (17 patients, 24%) and non-LVA group (55 patients, 76%). The [TpTe/ QTe]×100% (V₂ 25±7% vs. 22±5%, p=0.036) and TpTe/√RR (V₂ 109 ± 42 ms vs. 88 ± 22 ms, p=0.05, V₃ 108±39 ms vs. 91±27 ms, p=0.048) in V₂ and V₃ leads were prolonged in the LVA group after PCI. The [TpTe/QTe]×100% (28±9 % vs. 22±5%, p=0.025) and TpTe/√RR (129±53 ms vs. 99±41 ms, p=0.05) in V₃ lead were prolonged in the LVA group 24 hours after PCI. CONCLUSION: The mechanisms responsible for LVA after AMI may be associated with increased TDR, and PCI may have an important role in reducing LVA.