Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling
Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling
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DOI：
10.1155/2013/951234
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发表时间：
2013-01-01
影响因子：
--
通讯作者：
Dokos, Socrates
中科院分区：
文献类型：
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作者：
Al Abed, Amr;Guo, Tianruo;Dokos, Socrates
心房电活动的三维模型已开发与空间异构的电生理特性。根据男性Visible Human数据集重建的心房几何结构包括大体解剖特征，如中央和外周窦房结（SAN）、心房内连接、肺静脉、下腔静脉和上级腔静脉以及冠状窦。用细胞内玻璃微电极记录了自发活动或电起搏的离体兔心脏组织标本的肌细胞膜电位。中央和外周SAN，右心房和左心房，和肺静脉肌细胞的动作电位分别使用一个通用的离子模型，具有三个现象学的离子电流分量：一个时间依赖性向内，一个时间依赖性向外，和一个漏电流。为了弥合单细胞离子模型与3D全心房模型的总体电行为之间的差距，优化了具有异质区域的简化2D组织盘，以获得电紧张负荷下每种细胞类型的参数。然后将参数并入3D心房模型中，其结果显示能够有节奏地兴奋心房的自发活动SAN。基于组织的离子模型的优化和建模过程概述是通用的，适用于基于图像的计算机重建和兴奋组织的模拟。
A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN), intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.