title: Computational Modeling of Healthy Myocardium in Diastole.
abstract: In order to better understand the mechanics of the heart and its disorders, engineers increasingly make use of the finite element method (FEM) to investigate healthy and diseased cardiac tissue. However, FEM is only as good as the underlying constitutive model, which remains a major challenge to the biomechanics community. In this study, a recently developed structurally based constitutive model was implemented to model healthy left ventricular myocardium during passive diastolic filling. This model takes into account the orthotropic response of the heart under loading. In-vivo strains were measured from magnetic resonance images (MRI) of porcine hearts, along with synchronous catheterization pressure data, and used for parameter identification of the passive constitutive model. Optimization was performed by minimizing the difference between MRI measured and FE predicted strains and cavity volumes. A similar approach was followed for the parameter identification of a widely used phenomenological constitutive law, which is based on a transversely isotropic material response. Results indicate that the parameter identification with the structurally based constitutive law is more sensitive to the assigned fiber architecture and the fit between the measured and predicted strains is improved with more realistic sheet angles. In addition, the structurally based model is capable of generating a more physiological end-diastolic pressure-volume relationship in the ventricle.
authors.affiliation: Department of Mechanical Engineering, University of Kentucky, 269 Ralph G. Anderson Building, Lexington, KY, 40506-0503, USA.
authors.forename: Amir
authors.initials: A
authors.lastname: Nikou
authors.affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Shauna M
authors.initials: SM
authors.lastname: Dorsey
authors.affiliation: Gorman Cardiovascular Research Group and Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: McGarvey
authors.affiliation: Gorman Cardiovascular Research Group and Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Gorman
authors.affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Burdick
authors.affiliation: Gorman Cardiovascular Research Group and Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA.|Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Pilla
authors.affiliation: Gorman Cardiovascular Research Group and Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Gorman
authors.affiliation: Department of Mechanical Engineering, University of Kentucky, 269 Ralph G. Anderson Building, Lexington, KY, 40506-0503, USA. wenk@engr.uky.edu.|Department of Surgery, University of Kentucky, Lexington, KY, USA. wenk@engr.uky.edu.
authors.forename: Jonathan F
authors.initials: JF
authors.lastname: Wenk
mesh_terms: D000818:Animals; D003971:Diastole / Q000502:physiology*; D020342:Finite Element Analysis; D006321:Heart / Q000000981:diagnostic imaging / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008955:Models, Cardiovascular; D009206:Myocardium; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology
keywords: Constitutive modeling; Finite element method; Left ventricle; MRI; Optimization