Summary

Background and objective: To determine if there is any significant difference between the effects of desflurane, isoflurane and sevoflurane on the QT interval, QT dispersion, heart rate corrected QT interval and QTc dispersion of the electrocardiogram.

Methods: The study was conducted in a prospective, double blind and randomized manner in a teaching hospital. Ninety ASA I patients, aged 16–50 yr, undergoing general anaesthesia for noncardiac surgery were studied.

Results: There was no significant change in QT intervals during the study in any group (P > 0.05). QT dispersion in the sevoflurane group 49 ± 14 ms vs. 37 ± 10 ms; in the desflurane group 55 ± 16 and 62 ± 21 ms vs. 35 ± 14 ms and in the isoflurane group 54 ± 26 and 59 ± 24 ms vs. 42 ± 19 ms were significantly increased at 3 and 10 min after 1 MAC of steady end-tidal anaesthetic concentration compared with baseline values (P < 0.05). QTc values in the sevoflurane group were 444 ± 24 and 435 ± 21ms vs. 413 ± 19 ms (P < 0.05), in the isoflurane group were 450 ± 26 and 455 ± 34 ms vs. 416 ± 34 ms (P < 0.05), in the desflurane group were 450 ± 26 and 455 ± 34 ms vs. 416 ± 34 ms (P < 0.05) at 3 and 10 min after reaching 1 MAC of anaesthetic concentration and significantly increased compared with baseline values. QTc dispersion increased significantly with sevoflurane 62 ± 14 ms vs. 45 ± 16 ms (P < 0.05); isoflurane 70 ± 36 ms at 3 min and 75 ± 36 ms at 10 min after reaching 1 MAC of anaesthetic concentration vs. 50 ± 24 ms (P < 0.05); desflurane 67 ± 25 ms at 3 min and 74 ± 27 ms at 10 min after 1 MAC concentration vs. 41 ± 22 ms (P < 0.05).

Conclusion: Sevoflurane, isoflurane and desflurane all prolonged QTd, QTc and QTcd but there were no significant intergroup differences.