62Visualization of left atrial sympathetic innervation activity and the effect of catheter ablation on activity patterns in patients with atrial fibrillation

Background: A novel cardiac gamma camera utilises the radiopharmaceutical Iodine-123 Meta-iodobenzylguanidine (123I –mIBG) to visualise cardiac sympathetic innervation. Physiologic uptake of 123I –mIBG provides anatomical quantification of autonomic nervous system (ANS) structures, with discrete uptake areas (DUA) located in the left atrium (LA) corresponding to main ganglionated plexi (GP) clusters that have previously not been able to be visualised. Purpose: The purpose of this study is to visualise cardiac sympathetic innervation patterns in AF patients and to assess the influence of radiofrequency (RF) ablation on DUA sites in the LA. Methods: Twelve AF patients (7 non-paroxysmal; 6 male, mean age 56±11) underwent cardiac computed tomography (CT) and 123I –mIBG nuclear imaging after isotope injection. Nuclear datasets were merged with the pre-acquired CT to generate a detailed anatomical map of cardiac sympathetic activity. The processed maps were imported to a 3D electroanatomical mapping system. High frequency stimulation (HFS) was performed using current recommended output settings at DUA sites indicating GP location and followed by targeted RF ablation. Additionally, HFS was performed in the expected anatomical GP areas. Circumferential pulmonary vein (PV) isolation with exit and entrance block confirmation was performed in all patients after DUA ablation. Follow up nuclear imaging was acquired after 5–7 days post ablation.