Papers Published

1. Henriquez, CS, Effect of the anisotropy ratio on directional differences in conduction behavior in a planar slab model of cardiac tissue, Annals of Biomedical Engineering, vol. 19 no. 5 (December, 1991), pp. 621-622 .
   (last updated on 2023/06/01)

   Abstract:
   Directional differences in the conduction behavior of a cardiac tissue preparation in a bath were studied using a bidomain model. The governing equations for the transmembrane, interstitial and extracellular potentials were solved using a combination of Successive Overrelaxation (SOR) and an explicit finite difference algorithm on a CRAY-YMP. The approach is similar to that used by Roth (Circ. Res., 1991), but modified by simplifying the extracellular field calculations to reduce simulation times. By applying a Dirichlet rather than a Neumann far field boundary condition, the interstitial radial current at the surface can be shown to be the same as that for an active bundle in an infinite volume conductor. As a result, only a small extracellular domain needs to be considered to calculate the transmembrane potentials. In contrast to our previous simulation results, the aforementioned numerical approach allows for the investigations of unequal anisotropy ratios and non-steady state conduction. Using a planar slab geometry of finite thickness, slow upstrokes can be associated with fast conduction along fibers (x direction) while fast upstrokes can be associated with slow conduction across fibers (y direction). This result, consistent with experimental observations, was found to depend on the difference in the ratio of intracellular and interstitial conductivity in the direction of conduction (x or y) and the direction across fibers from surface to center (z direction).

   Keywords:
   Biological Materials - Tissue;Computer Programming - Algorithms;