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.

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.