Abstract 15603: Electroanatomic Map Significantly Overestimates the Ablated Area in the Left Atrium Compared to Late Gadolinium Enhancement in Magnetic Resonance Imaging and This Difference Predicts Atrial Fibrillation Recurrence
INTRODUCTION: Three-dimensional electroanatomic mapping (EAM) is routinely used to mark ablated areas during radiofrequency ablation. We hypothesized that EAM overestimates scar formation in the left atrium and that the difference between intra-procedural EAM ablated area and post-procedural scar area in late gadolinium enhancement magnetic resonance imaging (LGE-MRI) predicts atrial fibrillation (AF) recurrence.
METHODS: Of the 235 patients who underwent initial ablation for AF at our institution between August 2011 and December 2012, we retrospectively identified 70 patients who had an MRI merged with intracardiac ultrasound, three-month LGE-MRI, and five months minimum follow-up. CARTO (Biosense Webster) was used during the ablation to map ablated left atrial surface area. Corview software (Marrek Inc) was used to quantify scar in three-month LGE-MRI. Unpaired t-tests and time-to-event analysis were performed on AF recurrence and no AF recurrence subsets.
RESULTS: Of the 70 patients, fifteen patients had AF recurrence with mean follow-up of 264 days. There was no statistical difference in age, gender, BMI, and prior history of hypertension, diabetes, sleep apnea, coronary artery disease, heart failure, and paroxysmal or persistent AF between responders and non-responders at baseline. As a percent of total left atrial surface area, the mean ablated area in EAM was 30.5±7.5% and the mean scar area in LGE-MRI was 9.4±4.6% (p-value <0.001). Time to event analysis showed neither EAM ablated area nor LGE-MRI estimated scar predicted AF recurrence but their difference significantly predicted AF recurrence with hazard ratio of 8.3 and p=0.048 between the highest and lowest quartiles of the difference.
CONCLUSIONS: In AF ablation, EAM ablation mapping significantly overestimates scar formation when compared to LGE-MRI. The difference between the ablated area in EAM and scar area in follow-up LGE-MRI predicts AF recurrence.
- © 2013 by American Heart Association, Inc.