Effects of halothane and sevoflurane on QT dispersion in paediatric patients.
BACKGROUND
The QT dispersion (QTd) of the ECG is an indirect measure of heterogeneity of ventricular repolarization which may contribute to complex ventricular arrhythmias. We compared the effects of halothane and sevoflurane on QTd, and heart-rate corrected QT dispersion (QTcd).


METHODS
Fifty ASA physical status I patients, aged 5-15 years, undergoing general anaesthesia were studied. A control ECG recording was printed before induction of anaesthesia. In the halothane group, anaesthesia was induced with halothane 4% in 2 : 1 ratio of air : O2 mixture and in the sevoflurane group with sevoflurane 8% in 2 : 1 ratio of air : O2 mixture. The ECG was recorded 1 and 3 min after induction of anaesthesia, 1 and 3 min after the administration of vecuronium 0.08 m.kg(-1) intravenous and 1 and 3 min after the tracheal intubation. All ECGs were analysed by two cardiologists blinded to the anaesthetic.


RESULTS
Although QTd increased in both groups following intubation, this difference was not statistically significant when compared with control values. Following intubation five patients in the halothane group had ventricular arrhythmias of short duration, whereas no arrhythmias were recorded in the sevoflurane group (P = 0.052). Following intubation, QTd (45 +/- 15 ms vs 40 +/- 14 ms) and QTcd (60 +/- 17 ms vs 55 +/- 16 ms) values in the halothane group were significantly greater than the sevoflurane group (P < 0.05).


CONCLUSIONS
Neither sevoflurane nor halothane caused a significant increase in QTd compared with control values before induction. Only QTd following intubation was significantly greater in the halothane group than the sevoflurane group.
Gürkan
Yavuz
Y
Department of Anaesthesiology and Reanimation, Kocaeli University School of Medicine, Kocaeli, Turkey.
Canatay
Hakan
H
Agacdiken
Aysen
A
Ural
Ertan
E
Toker
Kamil
K
D000293:Adolescent; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006221:Halothane / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D000077149:Sevoflurane
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D006221:Halothane