Transversal versus longitudinal current propagation on a cardiac tissue and its relation to MCG.

Recently, B. Roth and M. Woods [7] suggested a reexamination of MCG interpretation through currents transversal to the wave propagation direction. They also gave a formula J'(theta) for the dependence of the current intensity on the angle theta between straight fibers and the plane wave front. Here we study more general situations, including current injection at multiple points and curved fibers. We conclude that transversal currents are always present locally, in spite of electric pattern complexity and fiber curvature. Moreover, the J'(theta) relation holds locally. Nevertheless, computations indicate that macroscopically the far magnetic field may be similar to the one generated by a current dipole parallel to the wave propagation direction.