title: Varying degrees of ventricular unloading in the heterotopic rat heart transplant model demonstrated by magnetic resonance imaging.
abstract: OBJECTIVE
  Left ventricular assist device placement is an increasingly common treatment for cardiac failure, resulting in cardiac unloading and potentially reversing the remodelling changes seen in heart failure. A popular animal model for human ventricular unloading is the rodent heterotopic non-working heart transplant; the volume loading status of this preparation is important to interpreting the resulting reverse remodelling yet has not been previously investigated. This study was designed to assess the variability of left ventricular volume loading in the rodent transplant model.
  
  
  METHODS
  Heterotopic abdominal heart transplant was performed on syngeneic rats; high resolution cine magnetic resonance imaging was subsequently performed on the heterotopic transplanted hearts in anesthetised rats, after variable post-transplant recovery times, in order to assess ventricular loading status.
  
  
  RESULTS
  Highly variable left ventricular volume loading status was demonstrated, with some hearts exhibiting considerable ventricular filling and ejection.
  
  
  CONCLUSIONS
  These observations call into question the assumption that studies using this model are consistently examining fully unloaded ventricles, and indicate the desirability of in vivo imaging of such hearts to quantify the degree of ventricular loading.
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, U.K.;
authors.forename: Carolyn A
authors.initials: CA
authors.lastname: Carr
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, U.K.;
authors.forename: Daniel
authors.initials: D
authors.lastname: Ball
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, U.K.;
authors.forename: Damian J
authors.initials: DJ
authors.lastname: Tyler
authors.affiliation: Nuffield Department of Surgery, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, U.K.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bushell
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, U.K.;
authors.forename: Amelia
authors.initials: A
authors.lastname: Sykes
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, U.K.;
authors.forename: Kieran
authors.initials: K
authors.lastname: Clarke
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, U.K.;
authors.forename: Rhys D
authors.initials: RD
authors.lastname: Evans
keywords: heart failure; heart transplant; heterotopic; magnetic resonance imaging; unloading