Effect of myocardial anisotropy on the torso current flow patterns, potentials and magnetic fields

The effects of myocardial anisotropy on the torso current how patterns, vol tage and the magnetic held were examined using an anatomically realistic to rso model of an adult male subject. A finite element model of the torso was built with 19 major tissue types identified. The myocardial fibre orientat ion in the heart wall was included with st voxel resolution of 0.078 x 0.07 8 x 0.3 cm. The fibre orientations from the canine heart which are availabl e in the literature were mapped to our adult male subject's human heart usi ng deformable mapping techniques. The current and potential distribution in the whole torso were computed using an idealized dipolar source of +/-1.0 V in the middle of the septum of the heart wall as a boundary condition. An adaptive finite element solver was used. Two cases were studied. In one ca se the myocardium was isotropic and in the other it was anisotropic. It was found that the current density distribution shows a very noticeable differ ence between the isotropic and anisotropic myocardium. The resultant magnet ic held in front of the torso was computed using the Biot-Savart law It was found that the magnetic field profile was slightly affected by the myocard ial anisotropy. The potential on the torso surface also shows noticeable ch anges due to the myocardial anisotropy.