Abstract Body (Do not enter title and authors here): Introduction: Current US guidelines and recent trial data recommend patients with comorbid heart failure (HF) and atrial fibrillation (AF) should be considered for catheter ablation. Care disparities between urban and rural areas remain a focus of ongoing investigation.

Research Question: We describe how catheter ablation rates among patients with comorbid AF and HF vary based on settlement pattern.

Methods: We used the Epic Cosmos database, which includes nationally-representative data from over 1,500 electronic health record systems, to examine trends in utilization of catheter ablation in patients with AF and HF. Patients were identified if they had at least two encounters between 2015 and 2024 with ICD-10 codes for each of AF and HF. Geosocial measures including Rural Urban Commuting Area (RUCA) and Social Vulnerability Index (SVI) were used for the analysis. RUCA is a measure of population density, urbanization, and commuting time. SVI quantifies geographic variation in social vulnerability. The primary outcome of interest was catheter ablation for atrial fibrillation, identified by CPT code. Patients were followed until the outcome of interest or 12/31/2024, whichever was earlier.

Results: We identified 2,646,219 patient records with HF and AF with an overall ablation rate of 5.2%. The ablation rate was greatest in metropolitan areas (5.6%) compared to micropolitan (4.9%, p < 0.05) and small town/rural areas (4.7%, p < 0.05) (Figure 1). There was no meaningful difference between patients below the median SVI in metropolitan areas (4.9%) and patients above the median SVI in micropolitan (4.9%) or small town/rural areas (4.8%). The annualized rate of catheter ablation per 100 new AF diagnoses is increasing at a numerically faster rate among metropolitan patients (1.2% per year) compared to micropolitan (0.98% per year) or small town/rural patients (0.96% per year) (Figure 2).

Conclusion: HF patients with both low social vulnerability and a metropolitan settlement pattern received AF ablation at the highest rates. Patients in a non-metropolitan setting were less likely to receive ablation, as were more socially vulnerable patients in a metropolitan setting.