The effect of propofol on frontal QRS-T angle in patients undergoing elective colonoscopy procedure

Propofol is a most commonly used anaesthetic drug for conscious sedation in outpatient procedures. Previous studies have shown that propofol may affect ventricular repolarization based on QT and Tp-e intervals. Frontal QRS-T angle is a marker of ventricular depolarization and repolarization difference. However, there is no study investigating the effect of propofol on frontal QRS-T angle. In this study, we aimed to investigate the effect of propofol on frontal QRS-T angle in patients undergoing colonoscopy procedure.

A total of 56 patients (53.5% females) who underwent colonoscopy procedure were included in this study. All patients underwent 12-lead surface electrocardiograms (ECGs) just before colonoscopy and 15 minutes after colonoscopy. QT interval, QTc interval, Tp-e interval, Tp-e/QT, Tp-e/QTc and frontal QRS-T angle were calculated from 12-lead ECGs.

The frontal QRS-T angle was significantly increased 15 minutes after colonoscopy compared to basal value (36.2 ± 24.3 vs. 29.5 ± 23.6, P = .003). In addition, repolarization parameters including QT, QTc and Tp-e intervals were significantly prolonged at 15 minutes after colonoscopy compared to basal value, except Tp-e/QT and Tp-e/QTc. Significant ventricular or supraventricular arrhythmias were not observed in any patient during the procedure.

In this study, we found that propofol administration increased the frontal QRS-T angle in patients undergoing colonoscopy procedure. Given that a prolonged frontal QRS-T angle is associated with ventricular arrhythmias, it may be safer to monitor those patients receiving propofol during colonoscopy procedures.