Inverse electrocardiographic problem for anisotropic cardiac muscle

A cardiac muscle can be considered as a bidomain, anisotropic conductor. The authors conducted theoretical as well as computer studies to evaluate the potential field generated by a heart with simple fiber orientation and realistic values of intra- and extracellular conductivities. The results show that simple excitation isochrones produce complex electric fields. In particular, a closed uniform double layer produces excess potential which could not be interpreted on the basis of the so-called solid-angle theory. The fact that the extracardiac potential is affected by the anisotropy in conductivity of the cardiac tissue will make the inverse problem more complicated. A discussion is presented of the feasibility of detecting the ´excess´ component from measurements in the external field.<>