title: Role of myocardial hypertrophy on acute and chronic right ventricular performance in relation to chronic volume overload in a porcine model: relevance for the surgical management of tetralogy of Fallot.
abstract: OBJECTIVE
  The age for correction of tetralogy of Fallot has progressively declined to the postnatal period, often despite an increased rate of transannular patch repair. However, the long-term effect of premature exposure to chronic pulmonary insufficiency on the right ventricle remains unknown. On the basis of the relationship between the duration of pressure overload and age, the role of previous pressure load-related hypertrophy on right ventricular (RV) performance after chronic volume overload was investigated in a porcine model.
  
  
  METHODS
  RV hypertrophy (RVH), induced by pulmonary artery banding, was studied in pigs with (RVH plus pulmonary insufficiency [PI]) and without (RVH) subsequent PI. The effect of volume overload was compared between these 2 groups and pigs without RVH but with PI and controls (sham). Both acute and chronic effects on RV function were studied using conductance technology and validated using echocardiography.
  
  
  RESULTS
  After chronic volume overload, the end-systolic and end-diastolic volumes were smaller in the RVH+PI group than in the PI group, including a lower pulmonary regurgitation fraction (25% ± 5% vs 35% ± 5%; P = .002). RVH resulted in better preserved systolic function, confirmed by an increased preload recruitable stroke work slope (14.7 ± 1.8 vs 9.3 ± 1.3 Mw.s/mL; P = .025) and higher RV ejection fraction (51% ± 3% vs 45% ± 4%; P = .05). Myocardial stiffness was impaired in the RVH+PI group versus the PI group (β, 0.19 ± 0.03 vs 0.12 ± 0.02 mL(-1); P = .001), presenting restrictive physiology only in the condition associating RVH and PI.
  
  
  CONCLUSIONS
  The results of the present study have demonstrated that RVH attenuates the RV remodeling process related to chronic PI. It enables better preservation of contractility but at the cost of sustained diastolic impairment. These findings might help to determine the timing and strategy for repair of tetralogy of Fallot when RV outflow tract morphology indicates a definite need for transannular reconstruction.
authors.affiliation: Department of Cardiac Surgery, University Hospital of Ghent, Ghent, Belgium. Electronic address: thierry.bove@ugent.be.
authors.forename: Thierry
authors.initials: T
authors.lastname: Bove
authors.affiliation: Department of Pediatric Cardiology, University Hospital of Ghent, Ghent, Belgium.
authors.forename: Kristof
authors.initials: K
authors.lastname: Vandekerckhove
authors.affiliation: Department of Anesthesiology, University Hospital of Ghent, Ghent, Belgium.
authors.forename: Stefaan
authors.initials: S
authors.lastname: Bouchez
authors.affiliation: Department of Anesthesiology, University Hospital of Ghent, Ghent, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Wouters
authors.affiliation: Department of Histology and Human Pathology, University Hospital of Ghent, Ghent, Belgium.
authors.forename: Pamela
authors.initials: P
authors.lastname: Somers
authors.affiliation: Department of Cardiac Surgery, University Hospital of Ghent, Ghent, Belgium.
authors.forename: Guido
authors.initials: G
authors.lastname: Van Nooten
mesh_terms: D000367:Age Factors; D000818:Animals; D006348:Cardiac Surgical Procedures; D004195:Disease Models, Animal; D015150:Echocardiography, Doppler; D004548:Elasticity; D006439:Hemodynamics; D017380:Hypertrophy, Right Ventricular / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D009200:Myocardial Contraction; D018579:Patient Selection; D011665:Pulmonary Valve Insufficiency / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D013318:Stroke Volume; D013552:Swine; D013771:Tetralogy of Fallot / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D016278:Ventricular Function, Right; D017725:Ventricular Pressure; D020257:Ventricular Remodeling