The effect of sevoflurane and ondansetron on QT interval and transmural dispersion of repolarization in children.

BACKGROUND: This study evaluated the prolongation of QT interval by the combination of sevoflurane and ondansetron in pediatric patients. Additionally, transmural dispersion of repolarization as interval between the peak and end of the T wave (Tp-e) and Tp-e/QT ratio was also measured to assess the risk of ventricular arrhythmia.

METHODS: The 3-lead electrocardiography (ECG) in lead II was sampled at three stages: at preinduction, just before (Sevo alone) and finally, after administration of ondansetron (Sevo+Ondansetron) in 41 children aged from 3 to 12 years. The QT interval was corrected for heart rate using Bazett's formula. And, Tp-e interval was obtained, and Tp-e/QT ratio was calculated. For analysis of the changes of parameters, a repeated-measures analysis of variance was used to identify significant differences in QTc, Tp-e interval and Tp-e/QT ratio at the three epochs.

RESULTS: The mean QTc at preinduction period was 413.8 (20.8) ms. The mean Sevo alone and Sevo+Ondansetron QTcs were 432.5 (28.1) and 439.2 (27.6) ms, and the differences in QTc prolongation between stages were all significant (P < 0.01). Ondansetron increased Tp-e interval significantly; however, Tp-e/QT ratio was not different among three stages. There were no ECG abnormalities such as atrial or ventricular arrhythmia and T-wave abnormality in any patient.

CONCLUSIONS: Sevoflurane prolongs the QTc interval and its combination with ondansetron further increased this effect in children. However, the dispersion of ventricular repolarization was not significantly affected, and there were no adverse events such as ventricular arrhythmia in this study. The combination of sevoflurane and ondansetron may be clinically safe, but careful ECG monitoring is still advisable.