QT prolongation under sevoflurane in infants

Introduction QT interval prolongation may cause the potentially lethal tachyarrhythmia torsades de pointes ( 1 ). The cause of the QT interval prolongation may be a congenital mutation in genes encoding cardiac potassium and sodium channels ( 2 ) or be acquired following drug administration ( 3 ) or metabolic disorders ( 4 ). Among a few other drugs volatile anaesthetics prolong the QT interval. During the last few years sevoflurane has become the most used volatile anaesthetic for the induction of anaesthesia in infants. Methods This investigation, on infants aged from 1 to 6 months, was approved by the institutional ethic committee. Thirty‐six otherwise healthy infants due to elective surgery were included in our study The patients were randomly assigned to one of two treatment groups. Group S ( n = 24) was anaesthetised with sevoflurane, Group H was anaesthetised with halothane. ECG recordings were taken before the anaesthesia onset, 15 min after the first contact with the volatile anaesthetic and 60 min after the ending of the volatile gas exposition. QTc interval was calculated using the Bazett's formula ( 5 ). Results QTc interval was significantly ( P < 0.0002) (Table 1) lengthened 15 min after anaesthesia induction with sevoflurane as well as 60 min ( P < 0.01) after the ending of the gas exposition without any difference in age and gender. The QTc interval in patients anaesthetised with halothane did not show any significant change. Baseline + 15 min 60 min post QT (ms) Sevotlurane 250 ± 23 301 ± 19 † ‡ 279 ± 22 * ‡ Halothane 260 ± 20 274 ± 23 258 ± 22 QTc (ms) Sevoflurane 409 ± 20 473 ± 19 † ‡ 433 ± 15 † ‡ Halothane 417 ± 22 418 ± 20 407 ± 34 P < 0.05, P < 0.01 in intergroup comparison; P < 0.01 in comparison to baseline value. Data are mean ± SD. Conclusion Usually no preoperative ECG recording, genetic or metabolic examination is performed in infants prior to elective surgical intervention. Physicians should be aware that sevoflurane induction and anaesthesia significantly lengthens the QTc interval in infants.