Abstract 18016: Real Time MRI To Detect and Target Gaps in Radiofrequency Ablation Lesions
Introduction: Radiofrequency ablation is routinely used to treat numerous cardiac arrhythmias including atrial fibrillation. Due to the lack of any direct visualization of changes at the tissue level with ablation gaps remain in ablation lesion sets. In this study we investigated using MRI to identify these gaps in lesions sets and target them acutely.
Methods: The study was carried out in pigs (n=5). Two discrete lesions were created in the right atrium spaced 10 mm apart using the CARTO (Biosense Webster, Diamond Bar, CA) electro-anatomical mapping system under fluoroscopy. The animal was then moved to the MRI scanner (3T, Verio, Siemens Healthcare, Germany) where delayed enhancement image after gadolinium infusion was acquired and used to identify the lesions and the gap in between them. Using real time catheter visualization in MRI the gap area was ablated using MRI compatible catheters (MRI Interventions Inc, Irvine, CA).
Results: Panel A shows the two right atrial lesions and the gap in between as seen in MRI using delayed enhancement (lesions marked by white and green arrows). Panel B is a snap shot from the real time MRI showing the segmented right atrial shell with the lesions and the MRI catheter targeting the gap between the lesions. Panel C shows the delayed enhancement image acquired after ablation in the MRI scanner confirming that the gap area is ablated (yellow arrow). Panel D is a cross section of the right atrial tissue specimen showing the two lesions made using CARTO (white and green arrows) and the ablated gap area (yellow arrow) in between. We were able to detect gaps upto 2.6 mm in using delayed enhancement in MRI.
Conclusions: Real time MRI can be used to identify gaps in lesion sets and target them acutely potentially leading to significant improvement in outcomes of ablation procedures.
- © 2011 by American Heart Association, Inc.