title: Chronic heart failure modifies respiratory mechanics in rats: a randomized controlled trial.
abstract: OBJECTIVE
  To analyze respiratory mechanics and hemodynamic alterations in an experimental model of chronic heart failure (CHF) following myocardial infarction.
  
  
  METHODS
  Twenty-seven male adult Wistar rats were randomized to CHF group (n=12) or Sham group (n=15). Ten weeks after coronary ligation or sham surgery, the animals were anesthetized and submitted to respiratory mechanics and hemodynamic measurements. Pulmonary edema as well as cardiac remodeling were measured.
  
  
  RESULTS
  The CHF rats showed pulmonary edema 26% higher than the Sham group. The respiratory system compliance (Crs) and the total lung capacity (TLC) were lower (40% and 27%, respectively) in the CHF rats when compared to the Sham group (P<0.01). There was also an increase in tissue resistance (Gti) and elastance (Hti) (28% and 45%, respectively) in the CHF group. Moreover, left ventricular end-diastolic pressure was higher (32 mmHg vs 4 mmHg, P<0.01), while the left ventricular systolic pressure was lower (118 mmHg vs 130 mmHg, P=0.02) in the CHF group when compared to the control. Pearson's correlation coefficient showed a negative association between pulmonary edema and Crs (r=-0.70, P=0.0001) and between pulmonary edema and TLC (r=-0.67, P=0.0034). Pulmonary edema correlated positively with Gti (r=0.68, P=0.001) and Hti (r=0.68, P=0.001). Finally, there was a strong positive relationship between pulmonary edema and heart weight (r=0.80, P=0.001).
  
  
  CONCLUSIONS
  Rats with CHF present important changes in hemodynamic and respiratory mechanics, which may be associated with alterations in cardiopulmonary interactions.
authors.affiliation: Laboratório de Fisiologia Cardiovascular, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.|Programa de Pós-graduação em Ciências da Saúde, UFCSPA, Porto Alegre, RS, Brazil.
authors.forename: Deise M
authors.initials: DM
authors.lastname: Pacheco
authors.affiliation: Laboratório de Fisiologia Cardiovascular, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.
authors.forename: Viviane D
authors.initials: VD
authors.lastname: Silveira
authors.affiliation: Laboratório de Fisiologia Cardiovascular, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.
authors.forename: Alex
authors.initials: A
authors.lastname: Thomaz
authors.affiliation: Laboratório de Fisiologia Cardiovascular, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.|Programa de Pós-graduação em Ciências da Reabilitação, UFCSPA, Porto Alegre, RS, Brazil.
authors.forename: Ramiro B
authors.initials: RB
authors.lastname: Nunes
authors.affiliation: Laboratório de Fisiologia Cardiovascular, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.|Programa de Pós-graduação em Biociências e Reabilitação, Centro Universitário Metodista do IPA, Porto Alegre, RS, Brazil.
authors.forename: Viviane R
authors.initials: VR
authors.lastname: Elsner
authors.affiliation: Laboratório de Fisiologia Cardiovascular, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.|Programa de Pós-graduação em Ciências da Saúde, UFCSPA, Porto Alegre, RS, Brazil.|Programa de Pós-graduação em Ciências da Reabilitação, UFCSPA, Porto Alegre, RS, Brazil.
authors.forename: Pedro
authors.initials: P
authors.lastname: Dal Lago
mesh_terms: D000818:Animals; D006333:Heart Failure / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D015656:Respiratory Mechanics