Abstract
BACKGROUND: Catheter ablation is a common means of treatment for atrial fibrillation (AFib). This approach involves electrical isolation of the pulmonary veins (PVs) from the left atrium (LA). However, in patients with persistent AFib, outcomes remain suboptimal. In addition to PV isolation (PVI), additional substrate ablation is likely required to improve outcomes. Aside from PVI, drivers for AFib and substrate necessary for AFib maintenance are incompletely understood and may involve certain regions of LA. OBJECTIVE: This study aimed to use our previously developed approaches to visualize drivers of AFib and to identify their spatial correlation within the atrium. To accomplish this goal, we compared the spatial location of these AFib drivers from the LA before PVI (pre-PVI), as well as after PVI during AFib. METHODS: Intracardiac electrograms were collected from swine (n = 7) using the CARTO 3 mapping system and PentaRay multielectrode mapping catheter. Bipolar and unipolar intracardiac electrograms were analyzed using our recently developed novel signal processing approaches, and similarity scores for every catheter position were calculated to identify AFib drivers within the atria. These AFib drivers were spatially correlated with 9 anatomic hallmarks of LA, and the presence of focal activity was quantified. RESULTS: We demonstrated the ability to identify and track AFib drivers in a large-animal model using our similarity-score-based framework in both pre- and post-PVI AFib and successfully correlated these drivers with LA anatomic hallmarks while capturing their spatial and temporal changes. CONCLUSION: Our findings indicate that pre-PVI drivers for AFib were identified both within and outside the PV regions. Post-PVI drivers were located in different parts of LA. We also noted a predominance of non-PV drivers to be from the appendage, septal wall, and posterior wall. These data highlight the need for further research on these regions and underscore the importance of non-PV sites in AFib maintenance.