title: [Hemodynamic effects of propafenone in dogs anesthesized with halothane or isoflurane].
abstract: OBJECTIVE
  Several studies suggest that anaesthetic drugs influence the haemodynamic effects of the antiarrhythmic drugs. The aim of this study was to compare the haemodynamic effects of a standard dose of propafenone (1.5 mg/kg) on dogs anaesthetized with halothane or with isoflurane.
  
  
  METHODS
  Randomized laboratory animal study.
  
  
  METHODS
  Six dogs were anaesthetized with 1% of halothane-Group I, and six dogs with an equianaesthetic dosage of isoflurane (1.5%)-Group II. Dogs breathed in spontaneous ventilation. Haemodynamic monitoring was performed with a femural arterial catheter and a flow-directed pulmonary artery catheter and cardiac output was measured by thermodilution. After a haemodynamic assessment considered as initial a bolus of 1.5 mg/kg of propafenone was given during a period of 30 seconds and similar assessments were made 5, 15, 30 and 60 minutes after.
  
  
  RESULTS
  Before propafenone, heart rate was significantly higher in Group II-isoflurane (p < 0.05). After propafenone we found: In both Groups, a decrease in the cardiac output (p < 0.05) with the mean arterial pressure maintained; in Group I (halothane) a decrease in the stroke volume (p < 0.05) which was not found in Group II (p = ns); In Group II (isoflurane) a decrease in heart rate (p < 0.05) not found in Group I (p = ns). All the changes were higher at the 5th minute values. 30th minute and 60th minute values were not significantly different from initial values.
  
  
  CONCLUSIONS
  In dogs anaesthetized with halothane 1.2 MAC a reduction in the stroke volume, resulting in a cardiac output decrease, was observed, suggesting that propafenone increases the negative inotropic action of halothane. In dogs anaesthetized with isoflurane 1.2 MAC the decrease in cardiac output was similar to the decrease in heart rate, and therefore no reduction in the stroke volume was observed. The decrease in the heart rate found in this group but not in the halothane group was probably related with the beta-blocker action of the propafenone. Looking to the systemic vascular resistances, our study suggested that propafenone didn't have any vasodilator effect during halogenated anaesthesia.
authors: Laboratório de Experimentação Animal dos Hospitais, Universidade de Coimbra, HUC.
authors: J da S
authors: Jda S
authors: Viana
authors: J
authors: J
authors: Morais
authors: G
authors: G
authors: Castro
authors: F
authors: F
authors: Figueiredo
authors: A M
authors: AM
authors: Godinho
authors: P
authors: P
authors: Fonseca
authors: M
authors: M
authors: Freitas
authors: L A
authors: LA
authors: Providência
mesh_terms: D000758:Anesthesia; D000818:Animals; D004285:Dogs; D006221:Halothane / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects*; D007530:Isoflurane / Q000494:pharmacology*; D011405:Propafenone / Q000494:pharmacology*; D011897:Random Allocation
chemical_list: D011405:Propafenone; D007530:Isoflurane; D006221:Halothane
vernacular_title: Efeitos hemodinâmicos da propafenona no cão anestesiado com halotano ou isoflurano.