Papers Published

1. Cartee, L.A. and Plonsey, R., The effect of cellular discontinuities on the transient subthreshold response of a one-dimensional cardiac model, IEEE Trans. Biomed. Eng. (USA), vol. 39 no. 3 (1992), pp. 260 - 70 [10.125011] .
   (last updated on 2007/04/16)

   Abstract:
   Previous studies have examined the influence of the gap-junction discontinuity on the steady-state response of a cardiac cable to electrical defibrillation. It is important to understand when steady-state conditions may be assumed. For this reason, the transient, subthreshold behavior of a discontinuous cardiac cable is examined in this study. The behavior of the cable reflects two characteristics: (1) the continuous nature of the entire cable and (2) the isolated behavior of individual cells caused by the junction discontinuity. The results show two effective time constants of activation: a large time constant corresponding to the time constant of a continuous cable of equivalent length, and a small time constant reflecting the rapid activation of an isolated cell. The rapid activation establishes a voltage gradient, across each cell of the cable with one end of the cell hyperpolarized and the opposite end depolarized. This pattern of hyperpolarization and depolarization reaches a maximum value in approximately 3 μs and may play an important role in the mechanism of defibrillation

   Keywords:
   bioelectric phenomena;cardiology;cellular biophysics;physiological models;