The volatile anesthetics increase the sensibility of the myocardium or its conduction system to the action of endogenous and/or exogenous epinephrine, predisposing the animal to cardiac arrhythmias. Among the volatile anesthetics, sevoflurane and desflurane are quite recent drugs and even though they have antiarrhythmogenic characteristics, there aren’t studies comparing these properties. The aim of this work was to study comparatively the cardiac rhythm and observe occasional atrioventricular blockages in dogs anesthetized with desflurane and sevoflurane, receiving increasing doses of epinephrine. 20 healthy adult male and female mongrel dogs were used. The animals were separated in two groups (G1 and G2). In G1, anesthesia was induced with propofol (10mmg-1.kg-1IV) and maintained with sevoflurane (1.5 MAC). Thirty minutes after the begin of volatile anesthetic administration, the epinephrine infusion was initiated at a dose of 1mmg.kg-1.min-1. At each 10 minutes the dose was increased in 1mmg.kg-1.min-1 until 6mmg.kg-1.min-1. For G2, the same methodology was used, except that sevoflurane was replaced by desflurane (1.5 MAC). At each epinephrine dose, the non-sinusal cardiac beats were counted and the occurrence of atrioventricular blockages was evaluated. The numerical data were submitted to Profile analysis and Kruskall-Wallis. The results allow to conclude that desflurane reduces in a more efficient way the arrhythmia produced by epinephrine and also the occurrence of atrioventricular blockages.
arrhythmia; epinephrine; desflurane; sevoflurane
