Response of Epinephrine on Electrocardiogram During Thiopental and Methoxyflurane Anesthesia in Sheep

Abstract

Edjtehadi, M. and Mehrabani, D. 2003. Response of epinephrine on electrocardiogram during thiopental and methoxyflurane anesthesia in sheep. J. Appl. Anim. Res., 24: 89–94. Due to lack of information concerning thiopental and methoxyflurane- induced myocardium sensitizing to epinephrine in sheep, it was decided to choose sheep as an experimental animal model. The effects of epinephrine on electrocardiograms in thiopental-anesthetized animals showed a significant increase in heart rate, while in methoxyflurane anesthetized, animals no such increase was observed. The EKG intervals such as P, PR, QRS, QT, T and ST were significantly reduced in unanesthetized (non- treated) animals. But, in thiopental-anesthetized animals, the decrease was not observed in QRS and T intervals, but in methoxyflurane-anesthetized animals no decrease was observed in P, PR, QRS and T interval. Highly significant increase (P<0.01) was observed in T amplitude in untreated and, thiopental-anesthetized animals. The arrhythmogenic effects of epinephrine observed in this study were augmented with thiopental anesthetic; while the effect of epinephrine was not augmented by methoxyflurane anesthetic and it was able to prevent this effect. It. is concluded that intravenous use of epinephrine and methoxyflurane concomitantly in clinical circumstances is not hazardous as it is in man due to lack of sensitization of myocardium and/or potentiality for epinephrine effects.