Computational and Mathematical Methods in Medicine
Volume 2011 (2011), Article ID 375059, 8 pages
doi:10.1155/2011/375059
Research Article

How Hyperpolarization and the Recovery of Excitability Affect Propagation through a Virtual Anode in the Heart

Department of Physics, Oakland University, Rochester, MI 48309, USA

Received 16 September 2010; Accepted 16 December 2010

Academic Editor: Sivabal Sivaloganathan

Copyright © 2011 Nicholas P. Charteris and Bradley J. Roth. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Researchers have suggested that the fate of a shock-induced wave front at the edge of a “virtual anode” (a region hyperpolarized by the shock) is a key factor determining success or failure during defibrillation of the heart. In this paper, we use a simple one-dimensional computer model to examine propagation speed through a hyperpolarized region. Our goal is to test the hypothesis that rapid propagation through a virtual anode can cause failure of propagation at the edge of the virtual anode. The calculations support this hypothesis and suggest that the time constant of the sodium inactivation gate is an important parameter. These results may be significant in understanding the mechanism of the upper limit of vulnerability.