Pranav Bhagirath

214 Chapter 11 sequences from body surface potentials. The simulation model was able to incorporate patient-specific electrical parameters and rapidly perform whole-heart cardiac activation simulations. Further clinical validation of this workflow was performed in patients undergoing catheter ablation of idiopathic right- and left- ventricular outflow tract (RVOT and LVOT) premature ventricular contractions (PVC). In addition to the validation of the IPM algorithm, the influence of tissue impedance on the results of IPM was studied using two different volume conductor models (VCM). A homogeneous thoracic VCM was compared to an inhomogeneous VCM where, in addition to thoracic impedance, the resistance value of the lungs was included. In all cases, IPM located the ectopic focus in the correct cardiac compartment and identified all foci in close proximity to the ablation lesion (RVOT 8.4±3 mm, n=6 and LVOT 7.9±1.5 mm, n=2). The comparison performed in this study indicated a significant difference between homogeneous and inhomogeneous VCM, with the homogeneous VCM having a significantly higher localization error and failing to identify the focus in one RVOT case. The current, most frequently utilized BSPM technique (ECVUE™) uses a homogeneous torso conductor model. The clinical utility of this method has been demonstrated after extensive investigation 28, 29 . However, recent research advocates the integration of the various organs with their own specific impedance 30, 31 . This may especially be the case in patients with a high body surface area, pulmonary edema or myocardial infarction. These circumstances could substantially influence the BSP’s due to altered conductivity and resistivity conditions. These results suggested that although it is possible to perform IPM using a homogeneous VCM, an inhomogeneous VCM provides more accurate results. Clinical implications This proposed combined IPM and MRI strategy offers the prospect to study the electrical activation in relation to tissue characteristics for complex (supra-)ventricular tachycardia’s and scar based arrhythmias with clinically relevant accuracy. The design of the computational model allows for instantaneous integration of patient- specific characteristics such as tissue properties and its associated conductivity. These tissue properties can be easily obtained using MRI. Integration of these characteristics will enable the operator to provide more patient tailored therapy.