Two Biophysical Mechanisms of Defibrillation of Cardiac Tissue

✍ Scribed by Alain Pumir; Valentin I. Krinsky

• Book ID: 102612757
• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 450 KB
• Volume: 185
• Category: Article
• ISSN: 0022-5193
• DOI: 10.1006/jtbi.1996.0296

✦ Synopsis

We have studied the mechanisms whereby a strong electric shock terminates chaotic wave propagation in cardiac tissue (defibrillation). In a generic model of cellular excitable tissue with two variables, we have found two mechanisms: one based on excitation (E), and another based on de-excitation (D) of cells by the small scale periodic component of transmembrane potential induced by the shock. Symmetry properties of the current-voltage characteristics describing the dynamics of the fast ionic currents, along with the strength of the electric field determine which of these mechanisms operates. A prediction of this work to be tested experimentally is that upon increasing the electric field one mechanism may switch to another, resulting in the following unusual sequence of events: defibrillation is first possible by mechanism E at moderate fields, then impossible, and finally possible by mechanism D, at higher fields.