Henriquez C S, Trayanova N, Plonsey R
Department of Biomedical Engineering, Duke University, Durham, North Carolina 27706.
Biophys J. 1988 Jun;53(6):907-18. doi: 10.1016/S0006-3495(88)83172-2.
The intracellular and interstitial potentials associated with each cell or fiber in multicellular preparations carrying a uniformly propagating wave are important for characterizing the electrophysiological behavior of the preparation and in particular, for evaluating the source contributed by each fiber. The aforementioned potentials depend on a number of factors including the conductivities characterizing the intracellular, interstitial, and extracellular domains, the thickness of the tissue, and the distance (depth) of the field point from the surface of the tissue. A model study is presented describing the extracellular and interstitial potential distribution and current flow in a cylindrical bundle of cardiac muscle arising from a planar wavefront. For simplicity, the bundle is considered as a bidomain. Using typical values of conductivity, the results show that the intracellular and interstitial potential of fibers near the center of a very large bundle (greater than 10 mm) may be approximated by the potentials of a single fiber surrounded by a limited extracellular space (a fiber in oil), hence justifying a core-conductor model. For smaller bundles, the peak interstitial potential is less than that predicted by the core-conductor model but still large enough to affect the overall source strength. The magnitude of the source strength is greatest for fibers lying near the center of the bundle and diminishes sharply for fibers within 50 microns of the surface.
在携带均匀传播波的多细胞制剂中，与每个细胞或纤维相关的细胞内和组织间电位对于表征制剂的电生理行为非常重要，特别是对于评估每个纤维所贡献的源。上述电位取决于许多因素，包括表征细胞内、组织间和细胞外区域的电导率、组织的厚度以及场点距组织表面的距离（深度）。本文提出了一项模型研究，描述了由平面波前引发的圆柱形心肌束中的细胞外和组织间电位分布以及电流流动。为简单起见，该束被视为一个双域。使用典型的电导率值，结果表明，在非常大的束（大于10毫米）中心附近的纤维的细胞内和组织间电位可以由被有限细胞外空间包围的单根纤维（油中的纤维）的电位近似，因此证明了芯导体模型的合理性。对于较小的束，组织间电位峰值小于芯导体模型预测的值，但仍然大到足以影响整体源强度。源强度的大小对于位于束中心附近的纤维最大，而对于距表面50微米内的纤维则急剧减小。
