Corrected QT-Interval and Dispersion After Revascularization by Percutaneous Coronary Intervention and Coronary Artery Bypass Graft Surgery in Chronic Ischemia

Introduction. Electrocardiography parameters can predict cardiac events in ischemia. QT- interval parameters are potentially proposed as available non-invasive markers for assessing the ventricular homogeneity and electrical instability. Prolonged QT-interval (QTI) and QT dispersion (QTd) are predictors of poor prognosis and fatal arrhythmias. The improvement of cardiac perfusion may decrease QTI via percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery. The aim of this study was to compare the effects of PCI and CABG on QT parameters in chronic ischemia. Methods. A total of 141 consecutive patients with coronary artery disease (70 who underwent PCI and 71 who underwent CABG) were entered into the study. Standard 12-lead electrocardiograms were recorded immediately before the procedure, immediately post procedure, 24 hours post procedure, and 7 days post procedure; corrected QTI (QTc) and corrected QTd (QTcd) and their changes were assessed and compared across the two therapeutic groups. Results. QTc and QTcd reduced significantly after 7 days of revascularization. After PCI, QTc reduced from 444.7 +/- 46.9 msec to 427.4 +/- 40.6 msec and QTcd reduced from 47.1 +/- 23.3 msec to 38.1 +/- 1.1 msec. QTc increased immediately after CABG from 443.2 +/- 36.6 msec to 461.9 +/- 38.1 msec, but reduced within 7 days of the procedure to 430.2 +/- 28.2 msec. QTcd reduced from 49.6 +/- 23.2 msec to 30.9 +/- 3.9 msec. The trend of QTcd reduction were similar in the two therapeutic groups but the trend of QTc alteration was different in that QTc increased upwardly and then decreased after CABG. Conclusion. Revascularization in chronic ischemia can improve QTI parameters following both PCI and CABG.