Abstract 16277: Evaluation of Left Peri Atrial Cardiac Sympathetic Activity Using Mibg Scintigraphy Before and After Cryoballoon Ablation of Paroxysmal Atrial Fibrillation

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Introduction: Accelerated cardiac sympathetic activity has been implicated in the development of atrial fibrillation. Ablation or excision of atrial epicardial ganglia for the treatment of atrial fibrillation has been reported. However, visualization of the atrial neural network is considered difficult. We attempted to image the sympathetic innervation with 123 I-metaiodobenzylguanidine (MIBG) using a novel solid-state whole-body scanner (VERITON). Methods: We performed pulmonary vein isolation using a cryoballoon in 10 patients with paroxysmal atrial fibrillation. MIBG images using specific processing were evaluated before and 3 months after ablation to evaluate the neural network of the left peri-atrial cardiac sympathetic activity and its response to ablation. Discrete epicardial accumulation of MIBG was identified using MIBG images fused with atrial computed tomography images. We quantitatively calculated the discrete MIBG accumulation in each pulmonary vein within 2 cm from its ostium, which may have been modified by balloon ablation. Results: Discrete MIBG accumulation was generally reproducible in the pre- and postoperative evaluations. The discrete MIBG accumulation value was 2.8 per case, with an average count of 4.15х10 5 PROPCNTS. Of the overall 28 accumulations, 15 had disappeared and three had changed in accumulation level and location after ablation. There was no specific pattern of sympathetic image modification. However, the group in which accumulation disappeared had a significantly smaller cross-sectional area of the pulmonary vein than the group in which it did not (17.2±3.4 mm vs 19.7±1.7 mm, p=0.0056). For reference, the average cryoballoon size was 28 mm. Conclusions: The sympathetic innervation of the left atrium was visualized using MIBG imaging, and the image was modified by cryoballoon ablation. The ability to image sympathetic nerve modification by catheter ablation will be clinically useful.