The aim of this work was to compare the cardiac rhythm and observe occasional atrioventricular blockages in dogs anesthetized with desflurane and sevoflurane, receiving increasing doses of epinephrine.

Twenty adult dogs, males and females, clinically healthy were randomly distributed in 2 groups of 10 animals each (G1 and G2). In G1, anesthesia was induced by intravenous administration of propofol (10 mg/kg) and maintained with sevoflurane (1.5 MAC). 30 minutes after the begin of volatile anesthetic administration, the epinephrine infusion was initiated at a dose of 1 µg/kg/min. At each 10 minutes the dose was increased by 1 µg/kg/min until 6 µg/kg/min, respectively M1, M2, M3, M4, M5 and M6. 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 data were submitted to analysis of variance (ANOVA), followed by the Tukey test (p<0.05) and Kruskall-Wallis (p<0.1).

Sevoflurane led to a higher number of non-sinusal cardiac beats than desflurane (58±82 versus 0±0 at M3) (p<0.05) and (28±48 versus 2±6 at M4) (p<0.1) and the atrioventricular blockages were higher in dogs anesthetized with sevoflurane than with desflurane.

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.