Comparison of the Effects of Halothane, Isoflurane, and Sevoflurane on Atrioventricular Conduction Times in Pentobarbital-Anesthetized Dogs

Abstract

It is not known how sevoflurane affects the cardiac conduction system. We compared the effects of halothane, isoflurance, and sevoflurane on specialized atrioventricular (AV) conduction times in eight pentobarbital-anesthetized dogs. AV conduction times with three inhaled anesthetics at end-tidal concentrations of 1 and 2 minimum alveolar anesthetic concentration (MAC), were measured by His-bundle electrocardiography during both sinus rhythm and right atrial pacing at a slightly higher rate than sinus one. Heart rate and arterial pressure were simultaneously recorded. Halothane prolonged AV nodal conduction time during sinus rhythm (A-H interval) at 2 MAC compared with the control value, whereas isoflurane and sevoflurane did not alter the A-H interval, His-Purkinje conduction time (H-V interval), and ventricular conduction time (H-S interval) during sinus rhythm at 1 and 2 MAC. All three inhaled anesthetics did not change AV conduction times during right atrial pacing. No significant difference in AV conduction times was observed between isoflurane and sevoflurane. Heart rate during sinus rhythm remained unchanged despite a decrease in arterial pressure with three inhaled anesthetics. The property of sevoflurane and isoflurane which does not affect the cardiac conduction system may be important in the stability of the cardiac rhythm during anesthesia with these drugs.

Efeito da dexmedetomidina sobre a arritmia cardíaca induzida pela adrenalina em cães anestesiados pelo sevofluorano

“…Na análise individual, houve redução do número de BAV a partir de M4 até o final da avaliação nos dois grupos (Tab. 2), fato este ocorrido em virtude da estabilidade do ritmo cardíaco proporcionada pelo sevoflurano, o qual não interfere no sistema de condução cardíaca (Nakaigawa et al, 1995).…”

“…A redução dos valores de ESV, ao final do período experimental nos dois grupos, sugere que houve saturação de receptores, provavelmente do tipo α   (Rezende et al, 2000) associado ao efeito antiarritmogênico do sevofluorano (Novalija et al, 1998), pois houve redução da quantidade de complexos ventriculares ectópicos, a partir da dose de 3µg/kg/min de adrenalina.…”

“…Bernard et al (1990); Lowe et al (1996) e Mutoh et al (1997) observaram aumento da freqüência cardíaca basal de 30 a 40%, em cães, durante a administração de 1,2 a 2,0CAM de sevofluorano. Para Nakaigawa et al (1995), esse fármaco não promove alterações no sistema de condução cardíaca e é importante na estabilidade do ritmo cardíaco durante a anestesia.…”

Does the Choice of the Halogenated Anesthetic Influence Renal Function during Hemorrhagic Shock and Resuscitation?

“…[4,5] The depressant effect of halothane on baroreceptor reflex is higher than isoflurane and sevoflurane. [6,7] Halothane also depresses the myocardium more than equipotent doses of isoflurane or sevoflurane. [4,5,7] The renal mechanisms of the renin-angiotensin and sympathetic systems, which compensate hemorrhage, are responsible for the hormones and neurotransmitters that determine vasoconstriction and can lead to renal ischemia.…”

“…[6,7] Halothane also depresses the myocardium more than equipotent doses of isoflurane or sevoflurane. [4,5,7] The renal mechanisms of the renin-angiotensin and sympathetic systems, which compensate hemorrhage, are responsible for the hormones and neurotransmitters that determine vasoconstriction and can lead to renal ischemia. [8] Renal response to low-flow states includes reduction of renal blood flow, glomerular filtration rate, and urinary output, as well as increasing proximal tubular reabsorption.…”