Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Ablation Techniques D-PO02 - Poster Session II (ID 47) Poster

D-PO02-142 - Prophylactic Anterior Mitral Lines Targeting Anterior Left Atrial Fibrosis During Atrial Fibrillation Ablation Do Not Reduce Arrhythmia Recurrence (ID 224)

Abstract

Background: Ablation of left atrial (LA) fibrosis, as determined by voltage abnormality, has been associated with improved outcomes for atrial fibrillation ablation. Ablation of extensive anterior LA fibrosis without completion of an anterior mitral line (AML) may increase risk of reentrant atrial tachycardias.
Objective: To assess the utility of prophylactic AML in patients with anterior LA scar in patients undergoing AF ablation.
Methods: The proportion of anterior wall low voltage (<0.5mV) surface area relative to total anterior LA surface area were determined using electroanatomic maps (CARTO 3, Biosense Webster, Inc.) of 108 consecutive patients undergoing first-time persistent AF ablation. Prophylactic AML were created at the discretion of 5 experienced operators based on low voltage area. Outcomes for patients with prophylactic AML (n=28) were compared to those of the overall cohort (n=80) and controls matched on proportion of anterior wall scar (n=27). Frequency of arrhythmia recurrence (AF/AT) as well as arrhythmia intervention (DCCV and repeat ablation) over 2 years was assessed by the Kaplan-Meier method.
Results: Anterior wall scar burden was similar in the AML and control cohorts (79±23% vs 88±6%, respectively, p=0.5). There was no significant difference in arrhythmia-free survival in the AML group compared to control patients (70% vs. 76%, p=0.9). AML lines resulted in increased DCCV and repeat ablation in (26% vs. 0%, p=0.01). Bidirectional AML conduction block was achieved in 16 of 28 patients (57%) with trans-AML conduction time of 176 ± 41ms). There was a trend towards increased frequency of DCCV and repeat ablation in AML patients in whom conduction block was acutely achieved (43% vs 8%, p=0.07). Peri-mitral flutter was observed in 100% (4/4) of repeat ablations in those with prophylactic AML. Sensitivity analysis comparing outcomes of patients with initial maps created in AF vs. those of maps created in sinus rhythm showed no differences.
Conclusion: Prophylactic anterior mitral lines for modification of anterior LA fibrosis during AF ablation do not reduce risk of recurrent arrhythmia and may increase risk of DCCV and repeat ablation. The risk of recurrent arrhythmia related to unmodified anterior LA fibrosis is likely low.
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