A Model Study of the Effect of the Intercalated Discs on Discontinuous Propagation in Cardiac Muscle
Part of the
Advances in Experimental Medicine and Biology
book series (AEMB, volume 161)
There is considerable evidence (1,13,14,22,23) to support the existence of low resistance end-to-end junctions (gap junctions or connexons (10,12,17) which lie in the intercalated discs that make up the associated end-to-end plasma membranes of cardiac muscle cells. Even though these gap junctions are low resistance, they represent a significant discontinuity in the conductive medium. Indeed, while these low resistance contacts are low in the sense of permitting an adequate current to flow and excite the postjunctional cell, an often quoted value for the intercalated disc resistance, 1 ohm-cm2, would be an impediment to axial current flow comparable to the entire myoplasm of the cell. In order to study the effects of these discontinuities due to the intercalated discs on propagation in cardiac muscle a “microscopic” discontinuous cable model which includes the intercalated discs was developed.
KeywordsCardiac Muscle Conduction Velocity Sharp Discontinuity Cable Model Discontinuous Model
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