Bakir Azam Ahmad, Dokos Socrates
Annu Int Conf IEEE Eng Med Biol Soc. 2015;2015:25-8. doi: 10.1109/EMBC.2015.7318252.
Action potential propagation in cardiac tissue is mainly governed by highly resistive gap junctions, which causes the tissue to behave as a network of active cell nodes interconnected by resistors. This property causes the action potential propagation to be less dependent on the level of mechanical deformation. This study proposes that the electrical conductivity in cardiac electromechanical simulations should be held fixed relative to the material frame, reproducing the dominant effect of intercellular gap junctions on the tissue electrical resistance instead of the more commonly employed spatial frame. Our simulations showed that the implementation of gap junction-based conductivity resulted in similar activation times at given material point, irrespective of the level of deformation. In contrast, the activation time of a given material point using spatial-based conductivity was dependent on the deformation experienced by the tissue. These findings have implication on more complex electromechanical simulations such as spiral wave since gap junction-based conductivity is independent of contraction, in contrast to spatial-based conductivity. Therefore, selection of the appropriate electrical conductivity assumption is highly crucial in electromechanics models of cardiac tissue.
心脏组织中的动作电位传播主要由高电阻的间隙连接控制，这使得该组织表现为由电阻器相互连接的活跃细胞节点网络。这一特性导致动作电位传播对机械变形程度的依赖性较小。本研究提出，在心脏机电模拟中，电导率应相对于材料框架保持固定，以再现细胞间间隙连接对组织电阻的主要影响，而不是更常用的空间框架。我们的模拟表明，基于间隙连接的电导率实现导致给定材料点处的激活时间相似，而与变形程度无关。相比之下，使用基于空间的电导率时，给定材料点的激活时间取决于组织所经历的变形。这些发现对更复杂的机电模拟（如螺旋波）具有启示意义，因为基于间隙连接的电导率与收缩无关，这与基于空间的电导率不同。因此，在心脏组织的机电模型中，选择合适的电导率假设至关重要。
