Transmembrane potential distribution in a spherical heart during field stimulation: a 3-D finite element bidomain model

The objective of this study is to utilize a 3-D finite element bidomain model to examine the transmembrane potential of the heart that arises from an external electric field. The myocardium is modeled as a spherical shell with an anisotropy conductivity ratio of 9.2 in the intracellular space and 2.6 in the extracellular space. Fiber rotation from the epicardium to endocardium is also incorporated into the finite element model. The results from an applied uniform electric field external to the heart indicate that the transmembrane potential is sensitive to the orientation of the cardiac fibers to the external field. This result suggests that cardiac fiber orientation is an important feature when using models to simulate the heart's response to external applied fields.