Effect of coronary bypass surgery on QT interval dispersion as a measure of ventricular repolarization inhomogeneity

Assessment of QT interval dispersion, measured from standard 12-lead ECG and reflecting ventricular repolarization prolongation and inhomogeneity has proved to a sensitive method for identification of increased sudden death patients with coronary artery disease. The aim of the present study was to evaluate the effect of successful coronary artery bypass grafting (CABG) on the following repolarization parameters-QT interval dispersion (PTD), QT apex interval dispersion (QTaD) and QTc interval duration. The measurement were performed prior to and after CABG in 23 post-myocardial infarction patients. Statistically significant reduction of mean QTD and QTaD values was recorded after coronary bypass surgery. Thus, successful myocardial revascularization decreases myocardial electrical instability assessed by QT interval dispersion recordings.