Advertisement

CA-530-02 LOWER ABLATION INDEX IS REQUIRED FOR POST-ABLATION DENSE SCAR FORMATION AT THE LEFT ATRIAL POSTERIOR WALL REGIONS WITH MRI-LATE GADOLINIUM ENHANCEMENT

      Background

      Late gadolinium enhancement in magnetic resonance imaging (MRI-LGE) at the left atrial posterior wall (LAPW) is a surrogate of fibrotic remodeling and is often targeted in persistent atrial fibrillation (PrAF) ablation. It is unclear whether ablation efficacy differs between regions with and without LGE at the LAPW.

      Objective

      We aim to study the association of ablation index (AI) and post-ablation transmural scarring, in regions with pre-ablation MRI-LGE vs regions without.

      Methods

      A total of 14 PrAF patients who underwent pulmonary vein isolation and posterior wall debulking were included, and a total of 493 ablation lesions were analyzed. All patients had a pre-ablation MRI and a 3-month post-ablation MRI. Electroanatomic (EA) map was co-registered with pre-ablation MRI to delineate the posterior wall regions with and without LGE, respectively. EA map was then co-registered with post-ablation MRI to delineate regions of transmural scar by ablation. Ablation lesion parameters were collected within each region.

      Results

      Post-ablation dense scar formation was observed in 97.7% area of regions with LGE vs. 55.6% of regions without LGE (p = 0.003). Post-ablation dense scarring was associated with ablation lesions that had higher AI, in both regions with (p < 0.01) and without LGE (p = 0.01). However, the AI required to achieve dense scar was significantly lower in regions with LGE seen on pre-ablation MRI compared to regions without LGE (median AI with IQR: 379 (359,407) vs 393 (366,426), p = 0.02, MRI-LGE vs non-LGE). (Figure)