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窦房结钙、膜钟控制自律性的新机制为揭示窦性心律失常提供了帮助,但目前钙钟动力学模型仅处于单细胞水平。本文构建了窦房结中心和边缘的单细胞模型,并按照指数形式改变中心到边缘细胞的膜电容、大小、电导及细胞间偶联电导,根据解剖结构构建了窦房结和心房二维非匀质模型。采用五点差分和有限元方法分别对组织内细胞网格和边界进行处理。通过分段构造试函数的方法确定不规则的组织边界。定量实验表明,构建的中心和边缘单细胞模型的动作电位在幅度、周期、最大舒张期电位以及上升速率等方面符合相关报道。钙钟和膜钟对主导起搏位置和除极速率的作用以及房性早搏对窦房结自律性的影响等定量研究也符合相关实验研究。本模型为深入探讨钙、膜钟在窦房结自律性中的相对作用以及与心房电活动的关系提供了帮助,同时可为构建三维窦房结和心房器官模型等奠定基础。
The new mechanism of sinus node membrane calcium and membrane clock self-regulation is helpful to reveal sinus arrhythmia, but the current model of calcium clock kinetics is only at the single-cell level. In this paper, a single cell model of the center and margin of the sinus node was constructed, and the membrane capacitance, size, conductance and intercoupling conductance of the center to edge cells were changed exponentially. According to anatomical structure, Homogeneous model. Five-point difference and finite element method were used to deal with the cell grids and boundaries in the tissue respectively. An irregular organizational boundary is determined by constructing a trial function piecewise. Quantitative experiments show that the action potential of the constructed single-cell model of the center and the periphery is consistent with relevant reports in terms of amplitude, period, maximum diastolic potential and rising rate. The quantitative study of the effect of calcium bell and membrane clock on the dominant pacing location and depolarization rate and the effect of atrial premature beats on the sinus node compliance is also consistent with relevant experimental studies. This model is helpful to further explore the relative roles of Ca and Membrane clock in the sinus node self-regulation and the relationship with the activity of atrial electrical. At the same time, this model can lay the foundation for the construction of 3D sinus node and atrial organ model.