Impact of coronary artery bypass grafting on ventricular repolarization indexes

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. INTRODUCTION: Ventricular repolarization indexes (VRI) tend to be altered in patients with chronic coronary artery disease, which are associated with a higher risk of malignant arrhythmias and higher mortality. Coronary artery bypass grafting (CABG) is capable of reducing mortality, as well as improving arrhythmic burden in this population. However, we do not know whether these benefits can be explained by improvement in VRI. PURPOSE: To determine whether there is improvement in VRI after CABG, as well as to analyse possible effects of clinical and surgical variables on these indexes. METHODOLOGY: A total of 150 patients who underwent CABG were included. Through the evaluation of preoperative and hospital discharge electrocardiograms, the QT interval, the interval from the peak to the end of T wave (Tp-Te) and the Tp-Te/ QT ratio were analysed. The values obtained before and after CABG were compared, as well as their association with clinical and surgical variables. RESULTS: The population was predominantly male (77.3 %), mean age of 61.6±8.3 years-old and mean LVEF of 58.8±10.6 %. A reduction in the QT interval (398.93±34.68 vs 365.47±50.38 ms, p < 0.001), in the Tp-Te interval (72.2±17.2 vs 61.6±19.5 ms, p < 0.001) and in the Tp-Te/ QT ratio (0.18±0.17 vs 0.04±0.05, p = 0.004) after CABG. There was no correlation between VRI and clinical and surgical variables. CONCLUSION: CABG had a important impact in the reduction of QT and Tp-Te intervals, as well as the Tp-Te/ QT ratio, suggesting that the acute improvement in the coronary perfusion is directly associated with the improvement in these VRI.