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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.


Related in: MedlinePlus

Comparison of inflow velocity magnitude measured at the center of the mitral annulus as a function of time for the four heart models. SR, sinus rhythm; LBBB, left bundle branch block.
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Figure 7: Comparison of inflow velocity magnitude measured at the center of the mitral annulus as a function of time for the four heart models. SR, sinus rhythm; LBBB, left bundle branch block.

Mentions: The weak vortex structures in the failing hearts are associated with the low magnitude of mitral inflow velocity, which results from the low ejection fraction. Figure 7 compares the velocity magnitude at the center of the mitral annulus for the four canine hearts considered in the present study. The inflow velocities in the failing hearts are much smaller than those in the normal hearts. The peak inflow velocity for LBBB activation appears a little earlier than that for the sinus activation, both in normal and in failing hearts. The intraventricular flow patterns are also visualized by the velocity vectors on the mid-plane of the ventricle (Figure 8) at t = 0.10 s. Similar to the vortex structures in Figure 6, the velocity field in Figure 8 also reveals weak vortex patterns associated with low blood flow velocity in the failing hearts.


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)

Comparison of inflow velocity magnitude measured at the center of the mitral annulus as a function of time for the four heart models. SR, sinus rhythm; LBBB, left bundle branch block.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 7: Comparison of inflow velocity magnitude measured at the center of the mitral annulus as a function of time for the four heart models. SR, sinus rhythm; LBBB, left bundle branch block.
Mentions: The weak vortex structures in the failing hearts are associated with the low magnitude of mitral inflow velocity, which results from the low ejection fraction. Figure 7 compares the velocity magnitude at the center of the mitral annulus for the four canine hearts considered in the present study. The inflow velocities in the failing hearts are much smaller than those in the normal hearts. The peak inflow velocity for LBBB activation appears a little earlier than that for the sinus activation, both in normal and in failing hearts. The intraventricular flow patterns are also visualized by the velocity vectors on the mid-plane of the ventricle (Figure 8) at t = 0.10 s. Similar to the vortex structures in Figure 6, the velocity field in Figure 8 also reveals weak vortex patterns associated with low blood flow velocity in the failing hearts.

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.


Related in: MedlinePlus