Effects of sevoflurane or ketamine on the QTc interval during electroconvulsive therapy

To evaluate the effect of sevoflurane or ketamine on the corrected QT (QTc) interval and the interval from the peak to the end of the T wave (Tp-e) during electroconvulsive therapy (ECT) in patients with major depression.

This prospective, randomized, double-blinded study included 24 patients that were randomly allocated to receive sevoflurane (group S) or ketamine (group K) for ECT session. Group S patients received 8 % sevoflurane for anesthesia induction, which was maintained at 2-4 % until delivery of the electrical stimulus. Group K patients received a bolus of ketamine (1 mg/kg). The mean arterial pressure (MAP) and heart rate (HR) and the electrocardiogram (ECG) were recorded before (T1) and after induction of anesthesia (T2) and 0, 1, 3, and 10 min after the electrical stimuli ended (T3, T4, T5, and T6, respectively).

In both groups, the QTc interval was significantly longer at T2, T4, T5, and T6 than at baseline. The QTc interval was longer at T4, T5, and T6 in group S compared to that in group K, the Tp-e interval was significantly longer at T4 in group K both baseline and group S. The HR in group S was increased at T4 compared with group K. MAP was significantly higher after induction of anesthesia in group K compared to those in group S at all time points.

Although group S showed a prolonged QTc interval after ECT compared to group K, the Tp-e interval in both groups was not significantly affected clinically. Sevoflurane blunted MAP and peak HR.