Pranav Bhagirath

76 Chapter 4 ABSTRACT Background: Patient selection andprocedural guidanceof atrial fibrillation (AF) ablation is currently performed using multiple imaging modalities. Recent work suggests that a cardiacmagnetic resonance (CMR) based approach canprovide comparable information in a more integrated and cost-effective manner. Purpose: This study investigated the clinical utility and feasibility of a CMR based imaging and post-processing workflow for patient selection and procedural guidance of AF ablation. Methods and results: Eight patients scheduled for AF ablation underwent CMR examination using a 1.5T scanner. Images were post-processed using a combination of open-source and custom-written software. Acquisition and post-processing was performed in 40 ± 3.5 minutes. A left atrial (LA) shell was created in all patients (n=8) to evaluate the LA volume and sphericity. The biplane area-length underestimated the average LA volume by 15 ml when compared to semi-automatic segmentation. Patients undergoing their index procedure had a lower sphericity of 77 ± 4 whereas redo ablation patients had a high LA sphericity (85 ± 3). In redo patients (n=5), the LA shell containing information from the late gadolinium enhancement images correlated well with sites of ablation on the EAM of the index procedure. Not all gaps identified using the scar-map were of relevance for the ablation procedure. Conclusion: A single modality, CMR based imaging workflow, is clinically relevant, feasible, and offers the prospect to perform patient selection as well as procedural guidance of AF ablation. In addition, catheter ablation procedures could benefit from targeted (patient-specific) ablation strategy using LGE-CMR derived scar-maps.