Abstract 19405: Morphological and Functional Image Fusion - A Novel, Multidimensional Way to Locate Ganglionated Plexi
Introduction: Catheter ablation of ganglionated plexi (GP) as an add on to pulmonary vein (PV) isolation has been reported to significantly improve outcome of atrial fibrillation (AF) ablation. In order to facilitate localization of these GPs, a novel imaging procedure is proposed. The uptake of iodine-123 metaiodobenzylguanidine (mIBG, an analog of norepinephrine) detected at the atrial level is combined with 3D surface reconstruction from contrast computed tomography (cCT) or cardiac magnetic resonance (CMR).
Methods: A total of 15 patients (11 male, median age 60.9 yrs) underwent mIBG SPECT using a dedicated cardiac camera (D-SPECT, Spectrum Dynamics, SUMO protocol). The acquired data was merged with the 3D anatomical imaging and subsequently imported into the 3D electroanatomical mapping system (CARTO, Biosense Webster). Sites with focal mIBG uptake, higher than mediastinal activity, in the epicardial fat pads around the left atrium (LA) and right atrium (RA) were identified. During AF ablations, these sites were mapped and high frequency stimulation (HFS) was performed to confirm GP locations.
Results: In all pts, both the mIBG and CT or CMR scans were performed without any complications and the data were merged. Median number of GPs in non pre-ablated patients was 5 and their activity normalized to mediastinum ranged widely. At some locations, eg. distally inside the PVs, HFS failed to confirm a GP location despite high mIBG uptake. Similarly, sites close to the descending aorta were not confirmed and may represent para-aortic rather than epicardial GPs. Interestingly, at sites close to the posterior RA wall HFS resulted also in phrenic nerve capture, demonstrating that sympathetic nerves are arriving along arterial and other nerve structures and may be co-located. Exact localization is highly depending on accurate image registration (both during the image merge and the CARTO study).
Conclusion: Image fusion of mIBG and 3D imaging results in a novel type of functional imaging to localize GPs for AF ablation. Locations around both the RA and LA and activities vary individually. Further studies in larger patient cohorts with invasive HFS are needed to confirm these initial observations.
Author Disclosures: S. Ernst: Research Grant; Modest; Spectrum Dynamics. Consultant/Advisory Board; Modest; Biosense Webster. Speakers Bureau; Significant; Spectrum Dynamics. Consultant/Advisory Board; Significant; Rhonda Grey. F. Menichetti: None. R. Nathaniel: Employment; Significant; Spectrum Dynamics. R. Baavour: Employment; Significant; Spectrum Dynamics. J. Bomanji: None. S. Ben-Haim: Consultant/Advisory Board; Significant; Spectrum Dynamics.
- © 2014 by American Heart Association, Inc.