Abstract Body (Do not enter title and authors here): Background:
Patients with CHF at time of AF ablation are more likely to have earlier (<90 days) AF recurrence, more CHF exacerbations, and prolonged index hospitalization. The diagnosis of CHF in those with AF can be confounded by their overlapping symptoms leading to under-recognition and delays in care. This study aims to determine whether elevated left atrial mean pressure (LAP) at time of AF ablation, measured immediately after transseptal catheterization, allows for detection of previously undiagnosed and undertreated CHF, and whether this may serve as a marker for patients at higher risk of AF recurrence and rehospitalization.

Methods:
A retrospective chart review was performed of all patients ≥18 years old at an academic medical center with a diagnosis of AF and who underwent AF ablation between 5/2022 and 9/2023. The cohort was divided into those with LAP ≥15 mmHg and those with LAP <15 mmHg at time of AF ablation. Baseline demographics, comorbidities, readmission rates, GDMT, and antiarrhythmic prescription rates were collected.

Results:
This analysis included 238 patients (31.5% female). At time of ablation, 77 (32.4%) had a LAP ≥ 15 mmHg, of which 34 (44.2%) did not have a pre-existing diagnosis of CHF. Those with LAP ≥15 were more likely to be on RAAS inhibition (57.1% vs 43.5%, p=0.048), MRA (23.4% vs 8.7%, p=0.002), and SGLT2i (23.4% vs 10.6% p=0.009) compared with those with a normal LAP. While not reaching statistical significance, elevated LAP was associated with higher NT-proBNP at time of ablation (1657 vs 930 p=0.129) despite higher BMIs (34.8 vs 30.1, p<0.001), with a trend towards increased 90-day readmission (9.1% vs 3.7%, p= 0.088).

Discussion:
LAP measurement identified a significant number of patients undiagnosed with CHF (44.2%). Elevated LAP also trended toward higher NT-proBNP despite having a higher BMI. Although rates of GDMT were higher for those with LAP ≥15 mmHg, the group remained significantly undermedicated, particularly with SGLT2i (29.3%, p<0.001) and MRA (26.3%, p<0.001). This may indicate suboptimal GDMT for both HFrEF and HFpEF. While not reaching statistical significance, this lack of recognition of CHF and subsequent lapse in GDMT prescription likely influenced the trend towards increased 90-day readmissions post ablation (p=0.088). Further work is needed to determine if identification of patients with elevated LAP at time of AF ablation can be prospectively optimized on GDMT improve outcomes post ablation.