title: Reversible pulmonary trunk banding: VII. Stress echocardiographic assessment of rapid ventricular hypertrophy in young goats.
abstract: BACKGROUND
  Ventricle retraining with abrupt systolic overload can cause myocardial edema and necrosis, followed by late ventricular failure. Intermittent systolic overload could minimize the inadequacy of conventional pulmonary artery banding. The present study compared ventricle function under dobutamine stress in 2 protocols of systolic overload in young goats.
  
  
  METHODS
  Nineteen young goats were divided into 3 groups: sham (n = 7; no systolic pressure overload), continuous (n = 6; systolic overload maintained for 96 hours), and intermittent (n = 6; 4 periods of 12-hour systolic overload, paired with a 12-hour resting period). Echocardiographic and hemodynamic evaluations were performed daily. The myocardial performance index and ejection fraction were evaluated at rest and during dobutamine stress. The goats were then killed for morphologic evaluation.
  
  
  RESULTS
  The intermittent group underwent less systolic overload than the continuous group (P < .05). Nevertheless, both groups had increased right ventricular and septal masses compared with the sham group (P < .0002). Echocardiography revealed a major increase in right ventricular wall thickness in the intermittent group (+64.8% ± 23.37%) compared with the continuous group (+43.9% ± 19.26%; P = .015). Only the continuous group remained with significant right ventricular dilation throughout the protocol (P < .001). The intermittent group had a significantly better myocardial performance index at the end of the protocol, under resting and dobutamine infusion, compared with the continuous group (P < .012).
  
  
  CONCLUSIONS
  Both systolic overload protocols have induced rapid right ventricular hypertrophy. However, only the intermittent group had better preservation of right ventricular function at the end of the protocol, both at rest and during dobutamine infusion.
authors.affiliation: Radiology Institute, University of São Paulo Medical School, São Paulo, Brazil. guzfavaro@hotmail.com
authors.forename: Gustavo A G
authors.initials: GA
authors.lastname: Fávaro
authors.forename: Renato S
authors.initials: RS
authors.lastname: Assad
authors.forename: Maria C D
authors.initials: MC
authors.lastname: Abduch
authors.forename: Gustavo J J
authors.initials: GJ
authors.lastname: Silva
authors.forename: Guilherme S
authors.initials: GS
authors.lastname: Gomes
authors.forename: José L
authors.initials: JL
authors.lastname: Andrade
authors.forename: José E
authors.initials: JE
authors.lastname: Krieger
authors.forename: Luiz Felipe P
authors.initials: LF
authors.lastname: Moreira
mesh_terms: D000818:Animals; D003250:Constriction; D004195:Disease Models, Animal; D025401:Echocardiography, Stress; D004489:Edema, Cardiac / Q000000981:diagnostic imaging / Q000209:etiology; D006041:Goats; D006439:Hemodynamics; D017380:Hypertrophy, Right Ventricular / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D009200:Myocardial Contraction; D011651:Pulmonary Artery / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016278:Ventricular Function, Right; D017725:Ventricular Pressure