Pranav Bhagirath

202 Chapter 10 However, even if these conditions can be optimized, there still remain factors that may cause discrepancies. These include image misregistration due to patient respiration, inaccurate cardiac geometry due to image acquisition during different phases of the cardiac cycle and substantial regional variations in cardiac displacement during contraction and relaxation (ranging between 5-25 mm) (17, 18) . Especially the base of the heart moves 20 mm or more towards the apex. This is of particular importance, since all ectopic foci were located at the basal part of the heart. Motion related inaccuracies will probably have less influence on hearts with reduced function (less movement) or when analyzing foci from regions less susceptible to motion. A larger study will be needed to establish the impact of a screening approach prior to routine implementation. Future directions 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. CONCLUSION This study demonstrates the clinical applicability of an MRI based whole-heart IPM method in patients with idiopathic ventricular foci. There was a high localization accuracy between the focus identified with IPM and the ablation site on the EAM. The inter-observer agreement was high for both VCM’s. The IPM accuracy improved significantly when utilizing an inhomogeneous VCM. The integration of this IPM technique with EAM systems may facilitate patient-specific catheter ablation strategies.