QT dispersion within the first 6 months after an acute myocardial infarction: Relationship with systolic function, left ventricular volumes, infarct related artery status and clinical outcome

Introduction: We analysed QT dispersion within the first 6 months postinfar ction, its relationship with the main established risk stratifiers and its clinical value. Methods and results: In 55 patients with a first Q-wave myo cardial infarction the 12-lead electrocardiogram was scanned and digitised for analysis of QT dispersion (QT maximum-QT minimum) at first day (72 [61- 96] ms), first week (69 [47-90] ms), first month (67 [46-88] ms) and sixth month (47 [40-74] ms; P <0.0001 vs. first day). Cardiac catheterization was performed at first week and at sixth month; QT dispersion was not related to ejection fraction, left ventricular volumes, infarct related artery stat us or contractile reserve (improvement of the infarcted area with low-dose dobutamine); no relation was found between QT dispersion decrease from firs t week to sixth month with regional systolic function improvement. Finally, during a mean follow-up period of 35 +/- 22 months QT dispersion was not i ndependently related to clinical events. Conclusion: QT dispersion decrease s progressively during the first months after myocardial infarction. These changes should be taken into account to define cut-off values of clinical i nterest in this phase. This variable does not seem related to the classic p rognosis predictors. In a nonselected postinfarction population it has a lo w clinical value. (C) 2001 Elsevier Science Ireland Ltd. All rights reserve d.