The role of volume conductivities in simulation of implantable defibrillators

In the quest for patient specific models for predicting defibrillation efficacy, one of the questions is which tissue types to include into a volume conductor model of the torso. We present a comparison between a model consisting of 11 different tissue types to models with only a subset of of tissue types across a database of electrode orientations including transvenous, epicardial, and subcutaneous electrodes. The simulations show that the volume conductor models should at least include segmentations for the heart, lungs, blood, and bones, and possibly the fat layers and the amount of gaseous space in the stomach and intestines. The latter ones may be necessary for modeling subcutaneous electrode configurations and ICD ldquocansrdquo in the abdomen.