Figure 1.

Left: schematic of a blood vessel surrounded by myocardium, with fibers smoothly circumnavigating the vessel. The vessel wall has thickness t and conductivity σ_w, and the blood inside the vessel has conductivity σ_b. The outer radius of the vessel is a, and the surrounding myocardium has anisotropic conductivity in the intra- (σ_i) and extracellular (σ_e) space. Right: two identical blood vessels proximal to one another separated by spacing d and oriented by angle θ; the origin is situated at the mid-point between the two vessel centers.