Unpinning of a rotating wave in cardiac muscle by an electric field.
The possibility of terminating cardiac arrhythmias with electric fields of moderate intensity is a challenging problem from a fundamental point of view and an important issue for clinical applications. In an effort to understand how anatomical re-entries are affected by electric fields, we found that a weak shock, with an amplitude of an order of magnitude less than the defibrillating shock, may unpin the vortices rotating around the defects (obstacles). The unpinning results from a depolarization of the tissue near the obstacle, induced by an external electric field within a distance of order lambda approximately 1 mm. Unpinning was observed both in the FitzHugh model of excitable tissue, and in a specific Beeler-Reuter model of cardiac tissue. This theoretical observation suggests that anatomical re-entries can be transformed into functional re-entries, an effect that can be tested in experiments with cardiac muscle.
Pumir
A
A
Institut Non Linéaire de Nice, UMR 6618, CNRS Université de Nice Sophia - Antipolis 1361, Route des Lucioles, Valbonne, 06560, France. pumir@inln.unis.fr
Krinsky
V
V
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D004554:Electric Countershock; D006321:Heart / Q000503:physiopathology*; D008564:Membrane Potentials; D008955:Models, Cardiovascular