Effects of Repeated Application of Isoflurane and Desflurane on Electrocardiogram, Anaesthesia Induction, and Recovery Characteristics in Rats

Thirty male Wistar albino rats were equally divided into two groups. All the animals were sedated with 5 mg kg of xylazine hydrochloride, and then 2.5% isoflurane or 8% desflurane with 100% oxygen by mask induction were given and anaesthesia maintenance was continued for 60 min with 5.7% desflurane or 1.4% isoflurane. Anaesthesia applications were repeated on the 1, 3, and 7 d in both groups. Heart and respiratory rates, rectal temperature, and electrocardiogram recordings were monitored periodically at the control time and at the 15, 30, and 60 min during anaesthesia. Anaesthesia induction and recovery times were also controlled. Compared to the 1 d, the repeated administration of desflurane and isoflurane caused no statistically significant change in QT and QTc intervals. The P wave duration (ms) decreased on the 7 d in both groups (P<0.05), and the R wave amplitude (mV) significantly decreased on the 3 d in the desflurane group (P<0.05). Although significant differences in the QRS interval (ms) (P<0.001) and R wave amplitude (mV) on the 1 d (P<0.05) were found, their values changed within normal reference ranges and did not lead to left ventricular enlargement. However, anaesthesia induction (P<0.05) and recovery times (P<0.01-0.001) in the desflurane group were performed faster than the isoflurane group. We concluded that a repeated application of desflurane and isoflurane caused no significant QT and QTc prolongation and myocardial repolarisation abnormalities, whereas they decreased anaesthesia induction and recovery times.