Effect of dexmedetomidine on the QT interval in pediatric patients undergoing general anesthesia

Background: Recent years have seen an increase in the use of dexmedetomidine in pediatric patients presenting for surgical procedures. However, only a limited number of studies have evaluated its effects on the QT interval in this patient group. To address this lack of knowledge, we have evaluated the effects of dexmedetomidine on the QT interval in children receiving sevoflurane anesthesia. Methods: This study was a prospective case–control study in which pediatric patients presenting for anesthetic care were divided into two groups—the dexmedetomidine (D) and control (C) groups. Three electrocardiograms (ECGs) were obtained on each patient, including a baseline ECG (T₁) prior to anesthetic induction and an ECG after the induction of anesthesia with sevoflurane (T₂). In group D, the third ECG was obtained 2 min after the administration of dexmedetomidine, which in turn was started immediately after the T₂ ECG reading (T_3D); in group C, it was obtained 2 min after the T₂ reading (T_3C). Statistical analysis was performed using analysis of variance to compare the QT intervals at the three time points outlined above. Results: A total of 50 patients were recruited to the study, ranging in age from 1 to 16 [mean 7.9 ± 4.1 (SD) years]. There were 25 patients in group C and 25 in group D. There were no statistical differences in the demographics between the 2 groups. In group C, the QTc was noted to increase progressively with the administration of sevoflurane (T_3C vs. T₁; P = 0.006). In group D, following the administration of dexmedetomidine, there was a significant decrease in the QTc relative to the post-induction value [436 ± 25 (T₂) vs. 418 ± 17 ms (T_3D); P < 0.01]. Conclusion: A progressive lengthening of the QTc interval following the administration of sevoflurane was observed in the control group. In the dexmedetomidine group, there was a significant shortening of the QTc interval following the administration of dexmedetomidine compared to the length of the post-induction QTc interval and when compared to the control group.