Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Mapping & Imaging D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-190 - Reduction In Scar Depth With Time After Atrial Fibrillation Ablation (ID 490)

  E.G. Kholmovski: Honoraria/Speaking/Consulting Fee - MRI Interventions; Marrek. Stock or Stock Options - Non-Public (Including Start-up) - Marrek.


Background: Left atrial (LA) wall undergoes long term remodeling after AF ablation. Late gadolinium enhancement (LGE) MRI can be used to assess this remodeling. Dependence of LA scar thickness/depth on time after ablation has not been previously studied.
Objective: To study the change in depth of LA ablation scar over time.
Methods: The study cohort consisted of 209 patients who underwent initial AF ablation and multiple post-ablation MRI sessions. 630 LGE-MRIs were included in analysis. The LA wall was segmented and scar depth was evaluated as the amount of enhanced tissue in direction perpendicular to LA wall. Scar depths were classified into 3 groups: superficial (<1mm), moderate (1-2mm), and extensive (>2mm).
Results: On average, across all time points, scar areas were 40.5% superficial, 16.7% moderate, and 42.8% extensive in depth. The proportion of each category of scar depth varied over time (Fig. 1). Proportion of superficial depth scar was positively correlated (increased) with the number of months after ablation with R=0.2 (p<0.001). Proportion of extensive depth scar was negatively correlated (decreased) with R = -0.21 (p<0.001). Proportion of moderate depth scar was weakly correlated with R=0.09 (p=0.0264). Statistically significant reduction in proportion of extensive depth scar with time after ablation was observed (Fig. 1). Average scar depth was 1.48 mm for 3-6 months LGE-MRI, 1.40 mm for 6-12 months LGE-MRI, and 1.32 mm for LGE-MRI acquired > 12 months after ablation.
Conclusion: Reduction in LA scar depth over time after AF ablation was demonstrated using longitudinal LGE-MRI studies. This result indicates thinning of LA wall at ablation locations over time after AF ablation.