Modeling Defibrillation Electrode Performance

A boundary element (BE) model was developed of the electric potential field in the heart arising from electric potentials applied on implanted defibrillator electrodes. The model solved Laplace´s equation for potential and was implemented using the BE method with realistic torso structures. An efficient out-of-core solver was developed, allowing any size problem to be solved, subject only to computer speed and time available. A method was also developed that allowed matrices calculated in one problem to be used in other, similar problems, often reducing calculation times by an order of magnitude. Model validation included comparison with myocardial potentials from a finite element model and clinically found voltage and resistance at defibrillation threshold from 29 patients. The model was used in investigations of transvenous electrode configurations, with potential found for reduction in defibrillation voltage and energy. The BE model was successful in modelling the electric field in the torso, in predicting implantable defibrillator performance and in finding application in electrode performance studies