Effect of coronary artery bypass grafting and aneurysmectomy on QT dispersion in moderate or severe left ventricular dysfunction.

BACKGROUND The aim of the study was to evaluate the effect that coronary artery bypass grafting (CABG) and aneurysmectomy in the same session have on QT dispersion (QTd) in moderate or severe left ventricular dysfunction. METHODS Forty-four patients underwent QT interval analyses before and 1 month after aneurysmectomy and CABG. QT interval and QTd were corrected for heart rate using the square root formula of Bazett (QTCB), the cubic root formula of Fridericia (QTCF), and the linear formula of Sagie et al (QT CS ). RESULTS The mean pre- and postsurgery QTd results were 65.29 +/- 29.25 and 51.76 +/- 18.49 milliseconds, respectively; the corresponding findings for QT CF were 68.06 +/- 31.26 and 55.16 +/- 24.56 milliseconds; and the corresponding findings for QT CS were 66.53 +/- 32.22 and 51.10 +/- 18.29 milliseconds. With these 3 methods, the postoperative findings were significantly lower than the preoperative findings ( P < .05 for all). In contrast, the opposite was true with the QT CB method (preoperative 71.1 +/- 65.80 vs postoperative 76.43 +/- 7.96 milliseconds, P < .05). CONCLUSION The study showed that based on the methods of Fridericia (QT CF ) and Sagie et al (QT CS ), QT intervals are significantly decreased after CABG and aneurysmectomy.