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A 2D Electromechanical Model of Human Atrial Tissue Using the Discrete Element Method.

Brocklehurst P, Adeniran I, Yang D, Sheng Y, Zhang H, Ye J - Biomed Res Int (2015)

Bottom Line: Each cell is electrically coupled to neighbouring cells, allowing excitation waves to propagate through the tissue.Cell-to-cell mechanical interactions are modelled using a linear contact bond model in DEM.The developed DEM model is numerically stable and provides a powerful method for studying the electromechanical coupling problem in the heart.

View Article: PubMed Central - PubMed

Affiliation: Engineering Department, Lancaster University, Lancaster LA1 4YR, UK.

ABSTRACT
Cardiac tissue is a syncytium of coupled cells with pronounced intrinsic discrete nature. Previous models of cardiac electromechanics often ignore such discrete properties and treat cardiac tissue as a continuous medium, which has fundamental limitations. In the present study, we introduce a 2D electromechanical model for human atrial tissue based on the discrete element method (DEM). In the model, single-cell dynamics are governed by strongly coupling the electrophysiological model of Courtemanche et al. to the myofilament model of Rice et al. with two-way feedbacks. Each cell is treated as a viscoelastic body, which is physically represented by a clump of nine particles. Cell aggregations are arranged so that the anisotropic nature of cardiac tissue due to fibre orientations can be modelled. Each cell is electrically coupled to neighbouring cells, allowing excitation waves to propagate through the tissue. Cell-to-cell mechanical interactions are modelled using a linear contact bond model in DEM. By coupling cardiac electrophysiology with mechanics via the intracellular Ca(2+) concentration, the DEM model successfully simulates the conduction of cardiac electrical waves and the tissue's corresponding mechanical contractions. The developed DEM model is numerically stable and provides a powerful method for studying the electromechanical coupling problem in the heart.

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Full electromechanical model for a rectangular region of tissue. (a) t = 7.12 ms, (b) t = 37.12 ms, (c) t = 55.92 ms, and (d) t = 225.92 ms.
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fig7: Full electromechanical model for a rectangular region of tissue. (a) t = 7.12 ms, (b) t = 37.12 ms, (c) t = 55.92 ms, and (d) t = 225.92 ms.

Mentions: In this section, we present results from the full electromechanical tissue model described in Section 2.1. A region of tissue 5 mm in length and 3.2 mm in width was constructed with the fibre direction aligned with the y-axis, comprised of 10 k cells and 90 k particles. The full simulation took approximately 4 hours to complete 600 ms of simulated time. The computational time is approximately consumed as 50% on DEM calculations, 20% on electrical wave propagation, 20% applying contraction to each cell, and 10% solving the single-cell equations. A boundary condition was applied to the lowermost cells along the x-axis, fixing their movement in the y-direction. The top portion of tissue received a stimulus of 2 nA at t = 1 ms lasting for 2 ms. Several snapshots are presented in Figure 7 as the electrical wave propagates throughout the tissue and contraction occurs.


A 2D Electromechanical Model of Human Atrial Tissue Using the Discrete Element Method.

Brocklehurst P, Adeniran I, Yang D, Sheng Y, Zhang H, Ye J - Biomed Res Int (2015)

Full electromechanical model for a rectangular region of tissue. (a) t = 7.12 ms, (b) t = 37.12 ms, (c) t = 55.92 ms, and (d) t = 225.92 ms.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4637066&req=5

fig7: Full electromechanical model for a rectangular region of tissue. (a) t = 7.12 ms, (b) t = 37.12 ms, (c) t = 55.92 ms, and (d) t = 225.92 ms.
Mentions: In this section, we present results from the full electromechanical tissue model described in Section 2.1. A region of tissue 5 mm in length and 3.2 mm in width was constructed with the fibre direction aligned with the y-axis, comprised of 10 k cells and 90 k particles. The full simulation took approximately 4 hours to complete 600 ms of simulated time. The computational time is approximately consumed as 50% on DEM calculations, 20% on electrical wave propagation, 20% applying contraction to each cell, and 10% solving the single-cell equations. A boundary condition was applied to the lowermost cells along the x-axis, fixing their movement in the y-direction. The top portion of tissue received a stimulus of 2 nA at t = 1 ms lasting for 2 ms. Several snapshots are presented in Figure 7 as the electrical wave propagates throughout the tissue and contraction occurs.

Bottom Line: Each cell is electrically coupled to neighbouring cells, allowing excitation waves to propagate through the tissue.Cell-to-cell mechanical interactions are modelled using a linear contact bond model in DEM.The developed DEM model is numerically stable and provides a powerful method for studying the electromechanical coupling problem in the heart.

View Article: PubMed Central - PubMed

Affiliation: Engineering Department, Lancaster University, Lancaster LA1 4YR, UK.

ABSTRACT
Cardiac tissue is a syncytium of coupled cells with pronounced intrinsic discrete nature. Previous models of cardiac electromechanics often ignore such discrete properties and treat cardiac tissue as a continuous medium, which has fundamental limitations. In the present study, we introduce a 2D electromechanical model for human atrial tissue based on the discrete element method (DEM). In the model, single-cell dynamics are governed by strongly coupling the electrophysiological model of Courtemanche et al. to the myofilament model of Rice et al. with two-way feedbacks. Each cell is treated as a viscoelastic body, which is physically represented by a clump of nine particles. Cell aggregations are arranged so that the anisotropic nature of cardiac tissue due to fibre orientations can be modelled. Each cell is electrically coupled to neighbouring cells, allowing excitation waves to propagate through the tissue. Cell-to-cell mechanical interactions are modelled using a linear contact bond model in DEM. By coupling cardiac electrophysiology with mechanics via the intracellular Ca(2+) concentration, the DEM model successfully simulates the conduction of cardiac electrical waves and the tissue's corresponding mechanical contractions. The developed DEM model is numerically stable and provides a powerful method for studying the electromechanical coupling problem in the heart.

No MeSH data available.


Related in: MedlinePlus