Finite Element Model of the Heart
The electrical conductivity tensor data was assigned on a voxel-by-voxel basis to the 3-
dimensional model and on a pixel-by-pixel basis to the 2-dimensional model within the
multiphysics software package, COMSOL (COMSOL Multiphysics v. 3.3, Stockholm, Sweden).
Two-dimensional Model
In this preliminary model, a rectangular area of 80 x 80 mm was selected and a
quadrilateral mesh was implemented in which each pixel was assigned to an element in the mesh
for a total of 6400 elements.
An isotropic model was first undertaken by selecting a particular transverse image of the
heart near the base. For this case, the electrical conductivity tensor matrix was reduced to a
single-non-zero scalar value of 0.6 S/m. A voltage difference of 0.1 V was applied between
opposing boundaries and electrical insulation to the remaining 2 edges of the model (Figure 3-3).
Electric
insulation
Electric
insulation
Figure 3-3. Transverse image of the heart along the xy-plane, 2D isotropic model for validation
studies. (red=isotropic heart tissue, blue=non-tissue surroundings).