Repolarization parameters in patients with acute ST segment elevation myocardial infarction treated with primary percutaneous coronary intervention with respect to predischarge ST-T pattern: a preliminary study

Abstract

Background: Negative T wave and lack of ST segment elevation in predischarge ECG in ST-segment elevation myocardial infraction (STEMI) patients are given as markers of good prognosis. Repolarization duration, especially its late part (TpeakTend - TpTe), likewise ST-T patterns, is related to local post-myocardial infarction myocardial attributes. We analyzed the differences in QT parameters in STEMI patients with negative or not-negative T wave pattern in predischarge ECG.

Methods: The data from 83 STEMI patients (LVEF > 45%, first MI, one-vessel disease) who underwent successful percutaneous coronary intervention of infarct-related coronary artery (TIMI 3 flow) were collected. According to ST-T patterns in predischarge ECG, the cohort was divided into two groups: 38 patients with persistent ST elevation and/or non-negative T wave pattern (STT+), and 45 patients with negative T wave, without ST elevation (STT-). QT, QTpeak, and TpTe intervals were obtained from 5 consecutive beats of sinus rhythm 60-70 bpm between 6 a.m. and 8 a.m. from Holter recording, corrected to the heart rate (HR) with Bazett's formula.

Results: The study groups did not differ in gender, age, or treatment. No true antiarrhythmics were given. Both QTc and TpTec were longer in STT+ patients: 459 +/- 26 ms vs. 440 +/- 25 ms, p = 0.01 and 108 +/- 10 ms vs. 96 +/- 11 ms, p = 0.000015, respectively. Prolongation of late repolarization was found both in anterior and inferior infarction.

Conclusions: STEMI patients who underwent successful percutaneous coronary intervention of infarct-related coronary arteries and demonstrated persistent ST elevation, without negative T wave at hospital discharge, had a longer repolarization duration, especially the late phase of it. Further studies are necessary to assess the prognostic value of this finding.