Pranav Bhagirath

23 Multimodality imaging for patient evaluation and guidance of catheter ablation for atrial fibrillation BACKGROUND During the last decade, left atrium (LA) catheter ablation has emerged as an established non-pharmacological treatment of atrial fibrillation (AF), increasingly surpassing medicinal therapy (1-3) . Cardiac imaging plays a key role in patient selection and prediction of safety and efficacy for these LA procedures ( figure 1 ) (3-6) . The current guidelines advocate for an elaborate imaging approach and warrant a multimodality strategy (2;3;5;6) . In daily practice four different key, non-invasive modalities including transthoracic echocardiography (TTE), trans-esophageal echocardiography (TEE), computed tomography (CT) and cardiac magnetic resonance (CMR) are combined for assessment of underlying structural heart disease, exclusion of thrombus, identification of pulmonary vein (PV) anatomy and PV dimensions, and quantification of atrial function and dimensions (2;4) . Recent technological development allow for non-invasive therapy stratification using pre-procedural tissue characterization maps (7) . The extent of fibrosis, a surrogate for the progression of disease, has been utilized to predict procedural outcome defined as post ablative recurrence of AF (7;8) . Furthermore, evaluating the circumferentiality of the induced PV antrum ablation lesions, might also be valuable for subsequent procedures (9) . Onsite integration of electroanatomic maps (EAM) with CT or CMR can assist LA ablation procedures (4;5;10;11) . Peri-procedural use of previously acquired images, contributes towards improving therapeutic success (12;13) and reducing radiation exposure (14) . In this overview, the advantages and limitations of the different cardiac imaging modalities facilitating LA ablation for AF will be examined on their merits. The primary objective is to explore the potential overlap and redundancy of these techniques and to advocate for an optimization and standardization of the multimodality approach.