title: Effect of a bath on the epicardial transmembrane potential during internal defibrillation shocks.
abstract: Using a three-dimensional model of cardiac tissue, we consider a rectangular slab of tissue. We examine the effect of a defibrillating shock from an intracavitary electrode upon the epicardial transmembrane potential (Vm) for two cases: one in which the epicardium is bounded by air and another in which it is bounded by a conductive bath. We find that the inclusion of the bath changes the polarity of the steady-state Vm in the epicardial region that is closest to the shock electrode. In addition, the magnitude of Vm is increased dramatically if the bath is present; the degree of hyperpolarization increases twenty-fivefold, while the degree of depolarization increases elevenfold. The remaining bulk of the cardiac tissue is relatively unaffected by the inclusion of the bath.
authors.affiliation: Mathematical Institute, University of Oxford, U.K.
authors.forename: D C
authors.initials: DC
authors.lastname: Latimer
authors.forename: B J
authors.initials: BJ
authors.lastname: Roth
mesh_terms: D001494:Baths; D004553:Electric Conductivity; D004554:Electric Countershock; D008564:Membrane Potentials / Q000502:physiology*; D008955:Models, Cardiovascular; D010496:Pericardium / Q000502:physiology*; D013499:Surface Properties