Electric and magnetic fields from two-dimensional anisotropic bisyncytia.
Cardiac tissue can be considered macroscopically as a bidomain, anisotropic conductor in which simple depolarization wavefronts produce complex current distributions. Since such distributions may be difficult to measure using electrical techniques, we have developed a mathematical model to determine the feasibility of magnetic localization of these currents. By applying the finite element method to an idealized two-dimensional bisyncytium with anisotropic conductivities, we have calculated the intracellular and extracellular potentials, the current distributions, and the magnetic fields for a circular depolarization wavefront. The calculated magnetic field 1 mm from the tissue is well within the sensitivity of a SQUID magnetometer. Our results show that complex bisyncytial current patterns can be studied magnetically, and these studies should provide valuable insight regarding the electrical anisotropy of cardiac tissue.
D000818:Animals; D004553:Electric Conductivity; D004562:Electrocardiography; D006321:Heart / Q000502:physiology*; D008280:Magnetics; D008433:Mathematics; D008564:Membrane Potentials; D008954:Models, Biological