QT Dispersion as a Prognostic Indicator for Myocardial Viability: a Systematic Review

Introduction: QT interval represents duration of ventricular electrical systole, i.e., the time required for completion of both ventricular depolarization and repolarization. QT interval duration normally varies between leads on the electrocardiography due to variation of repolarization and re-excitability of different ventricular regions. QT dispersion, defined as the difference between maximum and minimum of QT interval duration, is considered a strong predictor of myocardial viability in cardiac disorders, particularly in ischemic heart diseases and myocardial infarction (MI). Regarding this, the current systematic review aimed to evaluate QT dispersion measurement as a simple and powerful prognostic indicator for predicting the risk of life-threatening arrhythmia, cardiac sudden death, and ventricular dysfunction in patients with MI. Furthermore, this study attempted to establish the reliability of QT dispersion in assessing the efficacy of reperfusion therapeutic strategies.      Materials and Methods: For the purpose of data collection, PubMed was searched for all prospective English trials, using keywords of “QT dispersion”, “myocardial viability”, and “myocardial infarction” or “MI”. Out of the 294 retrieved articles, seven studies met the inclusion criteria. Results: QT dispersion was concluded to be instrumental in predicting the risk of post-MI life-threatening ventricular arrhythmia and cardiac sudden death, as well as assessment of ventricular wall motion and response to reperfusion therapeutic strategies. Conclusion: According to the findings of the reviewed studies, QT dispersion is a reliable, simple, and applicable tool for myocardial viability assessment in patients with MI.