Background: The aim of this study was to investigate the effects on QT interval of the propofol-ketamine combination and the midazolam-fentanyl combination in anesthesia induction for cardiac surgery.

Methods: Between September 2020 and June 2021, a total of 9 5 c ardiac s urgery p atients ( 80 m ales, 1 5 f emales; mean age: 57±9.1 years; range, 26 to 76 years) were included. The patients were divided into two groups as Group PK (propofol-ketamine, n=50) and Group MF (midazolam-fentanyl, n=45). The 12-lead electrocardiographic and hemodynamic measurements were performed at three time points: before anesthesia induction, after anesthesia induction, and after endotracheal intubation. The measurements were evaluated with conventional Bazett's formula and a new model called index of cardio-electrophysiological balance.

Results: The evaluated QTc values of 95 patients after anesthesia induction were significantly prolonged with the Bazett's formula and the index of cardio-electrophysiological balance in Group PK (p=0.034 and p=0.003, respectively). A statistically significant QTc prolongation was observed with the index of cardio-electrophysiological balance after laryngoscopy and endotracheal intubation in Group PK (p=0.042). Hemodynamic parameters were also higher in Group PK.

Conclusion: Our study shows that the propofol-ketamine combination prolongs the QTc value determined by the Bazett's formula and the index of cardio-electrophysiological balance model. Using both QTc measurement models, the midazolam-fentanyl combination has no prolongation effect on QTc interval in coronary surgery patients.

Keywords : Cardiac anesthesia, electrocardiography, enhanced recovery after surgery, fentanyl, ketamine, long QT syndrome, midazolam, propofol