title: The role of elastic restoring forces in right-ventricular filling.
abstract: OBJECTIVE
  The physiological determinants of RV diastolic function remain poorly understood. We aimed to quantify the contribution of elastic recoil to RV filling and determine its sensitivity to interventricular interaction.
  
  
  RESULTS
  High-fidelity pressure-volume loops and simultaneous 3-dimensional ultrasound sequences were obtained in 13 pigs undergoing inotropic modulation, volume overload, and acute pressure overload induced by endotoxin infusion. Using a validated method, we isolated elastic restoring forces from ongoing relaxation using conventional pressure-volume data. The RV contracted below the equilibrium volume in >75% of the data sets. Consequently, elastic recoil generated strong sub-atmospheric passive pressure at the onset of diastole [-3 (-4 to -2) mmHg at baseline]. Stronger restoring suction pressure was related to a shorter isovolumic relaxation period, a higher rapid filling fraction, and lower atrial pressures (all P < 0.05). Restoring forces were mostly determined by the position of operating volumes around the equilibrium volume. By this mechanism, the negative inotropic effect of beta-blockade reduced and sometimes abolished restoring forces. During acute pressure overload, restoring forces initially decreased, but recovered at advanced stages. This biphasic response was related to alterations of septal curvature induced by changes in the diastolic LV-RV pressure balance. The constant of elastic recoil was closely related to the constant of passive stiffness (R = 0.69).
  
  
  CONCLUSIONS
  The RV works as a suction pump, exploiting contraction energy to facilitate filling by means of strong elastic recoil. Restoring forces are influenced by the inotropic state and RV conformational changes mediated by direct ventricular interdependence.
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Candelas
authors.initials: C
authors.lastname: Pérez Del Villar
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain javier.bermejo@salud.madrid.org.
authors.forename: Javier
authors.initials: J
authors.lastname: Bermejo
authors.affiliation: Department of Mathematical Physics and Fluids, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rodríguez-Pérez
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain Mechanical and Aerospace Engineering Department, University of California San Diego, La Jolla, CA, USA.
authors.forename: Pablo
authors.initials: P
authors.lastname: Martínez-Legazpi
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Benito
authors.affiliation: Department of Mathematical Physics and Fluids, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain.
authors.forename: J Carlos
authors.initials: JC
authors.lastname: Antoranz
authors.affiliation: Department of Mathematical Physics and Fluids, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain.
authors.forename: M Mar
authors.initials: MM
authors.lastname: Desco
authors.affiliation: Biomedical Image Technologies, Universidad Politécnica de Madrid & CIBER-BBN, Madrid, Spain.
authors.forename: Juan E
authors.initials: JE
authors.lastname: Ortuño
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Barrio
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Mombiela
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Yotti
authors.affiliation: Biomedical Image Technologies, Universidad Politécnica de Madrid & CIBER-BBN, Madrid, Spain.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Ledesma-Carbayo
authors.affiliation: Mechanical and Aerospace Engineering Department, University of California San Diego, La Jolla, CA, USA Institute for Engineering in Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Del Álamo
authors.affiliation: Department of Cardiology, Hospital General Universitario Gregorio Marañón, Madrid, Spain Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernández-Avilés
mesh_terms: D000818:Animals; D003971:Diastole / Q000502:physiology; D004548:Elasticity; D009200:Myocardial Contraction; D013552:Swine; D013556:Swine, Miniature; D016278:Ventricular Function, Right
keywords: Diastolic function; Diastolic stiffness; Hemodynamics; Relaxation; Right ventricle