Pranav Bhagirath

77 Implementation of a standardized cardiac magnetic resonance based workflow for atrial fibrillation catheter ablation BACKGROUND Patient selection and procedural guidance of atrial fibrillation (AF) ablation is often performed using multiple imaging modalities such as echocardiography, computed tomography and cardiac magnetic resonance imaging (CMR) [1;2] . However, it has recently been suggested that a single modality, CMR based approach can provide a comparable diagnostic yield in a more time- and cost-efficient manner [3] . Commercially available CMR pulse sequences have been applied to obtain detailed information about left atrial appendage (LAA) thrombus [4] and optional parameters such as pulmonary vein (PV) morphology [5] , and left atrial (LA) volume [6] . Furthermore, CMR offers unmet capabilities for tissue characterization in the thin LA wall [7;8] . This tissue information may be used to identify potential electrical re-entry circuits [9] and to design patient specific ablation strategies [10] . The current lack of uniformity for LA imaging however, poses significant limitations. This study proposes a standardized CMR based imaging and post-processing workflow for patient selection and procedural guidance of AF ablation. Clinical utility and feasibility were examined by evaluating: (1) the ability to assess the following parameters: LAA thrombus, LA volume and sphericity, (2) the capability to facilitate procedural guidance by fusion of CMR-derived LAmodels with the electro-anatomical mapping (EAM) system, and (3) the correlation between sites of ablation and scar localization on the LA model. METHODS Patient Population The study population consisted of 8 patients undergoing an index (n=3) or redo (n=5) catheter ablation procedure for paroxysmal or persistent AF. The study complied with the declaration of Helsinki and received approval from the local ethical committee and the institutional scientific board. Written informed consent was obtained from the study subjects.