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A New MRI-Based Model of Heart Function with Coupled Hemodynamics and Application to Normal and Diseased Canine Left Ventricles.

Choi YJ, Constantino J, Vedula V, Trayanova N, Mittal R - Front Bioeng Biotechnol (2015)

Bottom Line: The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver.The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart.We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Johns Hopkins University , Baltimore, MD , USA ; Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA.

ABSTRACT
A methodology for the simulation of heart function that combines an MRI-based model of cardiac electromechanics (CE) with a Navier-Stokes-based hemodynamics model is presented. The CE model consists of two coupled components that simulate the electrical and the mechanical functions of the heart. Accurate representations of ventricular geometry and fiber orientations are constructed from the structural magnetic resonance and the diffusion tensor MR images, respectively. The deformation of the ventricle obtained from the electromechanical model serves as input to the hemodynamics model in this one-way coupled approach via imposed kinematic wall velocity boundary conditions and at the same time, governs the blood flow into and out of the ventricular volume. The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver. The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart. We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

No MeSH data available.


Schematic of the electromechanical model.
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Figure 2: Schematic of the electromechanical model.

Mentions: Briefly, the electromechanical model is composed of two parts: an electrical component and a mechanical component. The electrical component describes the propagation of electrical activity, which is governed by the mono-domain reaction-diffusion equations. The Luo–Rudy dynamic model (Luo and Rudy, 1994a) is employed to represent membrane dynamics; it is a generic action potential model that has been used in a number of previous electromechanical models (Luo and Rudy, 1994a,b; Kerckhoffs et al., 2006; Provost et al., 2011). The mechanical component describes the contraction of the heart and is based on the equations of continuum mechanics. The myocardium was assumed to be hyperelastic, nearly incompressible orthotropic material. The generation of active tension by the myocytes was represented by the Rice et al. (2008) model, which was parameterized for the canine heart by matching the data obtained from electromechanical wave imaging (an ultrasound experimental technique) as described earlier (Provost et al., 2011). A schematic of the electromechanical model is presented in Figure 2. A time step of 0.01 and 0.1 ms was used in the electrical and mechanical components of the model, respectively, as established in previous studies (Plank et al., 2008; Gurev et al., 2011). The parameters associated with cell-level modeling can be downloaded from the CellML website, https://www.cellml.org/.


A New MRI-Based Model of Heart Function with Coupled Hemodynamics and Application to Normal and Diseased Canine Left Ventricles.

Choi YJ, Constantino J, Vedula V, Trayanova N, Mittal R - Front Bioeng Biotechnol (2015)

Schematic of the electromechanical model.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585083&req=5

Figure 2: Schematic of the electromechanical model.
Mentions: Briefly, the electromechanical model is composed of two parts: an electrical component and a mechanical component. The electrical component describes the propagation of electrical activity, which is governed by the mono-domain reaction-diffusion equations. The Luo–Rudy dynamic model (Luo and Rudy, 1994a) is employed to represent membrane dynamics; it is a generic action potential model that has been used in a number of previous electromechanical models (Luo and Rudy, 1994a,b; Kerckhoffs et al., 2006; Provost et al., 2011). The mechanical component describes the contraction of the heart and is based on the equations of continuum mechanics. The myocardium was assumed to be hyperelastic, nearly incompressible orthotropic material. The generation of active tension by the myocytes was represented by the Rice et al. (2008) model, which was parameterized for the canine heart by matching the data obtained from electromechanical wave imaging (an ultrasound experimental technique) as described earlier (Provost et al., 2011). A schematic of the electromechanical model is presented in Figure 2. A time step of 0.01 and 0.1 ms was used in the electrical and mechanical components of the model, respectively, as established in previous studies (Plank et al., 2008; Gurev et al., 2011). The parameters associated with cell-level modeling can be downloaded from the CellML website, https://www.cellml.org/.

Bottom Line: The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver.The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart.We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Johns Hopkins University , Baltimore, MD , USA ; Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA.

ABSTRACT
A methodology for the simulation of heart function that combines an MRI-based model of cardiac electromechanics (CE) with a Navier-Stokes-based hemodynamics model is presented. The CE model consists of two coupled components that simulate the electrical and the mechanical functions of the heart. Accurate representations of ventricular geometry and fiber orientations are constructed from the structural magnetic resonance and the diffusion tensor MR images, respectively. The deformation of the ventricle obtained from the electromechanical model serves as input to the hemodynamics model in this one-way coupled approach via imposed kinematic wall velocity boundary conditions and at the same time, governs the blood flow into and out of the ventricular volume. The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver. The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart. We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.

No MeSH data available.