Abstract Body (Do not enter title and authors here): Background:
Post-ablation atrial fibrillation (AF) inducibility has been associated with AF recurrence and is often used as an endpoint for Pulmonary Vein Isolation (PVI). Little is known regarding factors affecting inducibility after PVI, as AF inducibility is common even after PV isolation. Prolonged episodes of untreated AF can result in remodeling of the atrium and the formation of new arrhythmogenic substrate, which may make treatment of AF more challenging. We hypothesized that longer diagnosis-to-ablation time (DAT) is associated with higher rates of post-PVI AF inducibility.

Objective:
To evaluate DATs in cases of inducible vs. non-inducible AF post ablation.

Methods:
A single-center, retrospective analysis of 168 consecutive patients who underwent 1^st time PVI between 1/1/2022 and 12/01/2023 was performed. Following PVI, inducibility of AF was tested by programmed stimulation using decremental pacing in 50ms windows for 10 seconds each (from 400 ms down to 200 ms or until loss of 1:1 atrial capture). Results were categorized by type of rhythm induced (non-inducible, AF) and duration (sustained, non-sustained). DAT was obtained from review of the medical records. Descriptive statistics were used to compare demographics and AF type, and parametric and non-parametric tests were used for analysis of the diagnosis-to-ablation window and its relationship to inducibility.

Results:
There was no difference in demographic data or AF type between the two groups. 85 patients (50.6%), had no inducible AF. 83 out of 168 cases (49.4%) had inducible sustained AF. Overall DATs ranged from 0 to 40 years. DAT was significantly higher in the inducible vs. non-inducible groups (3.810 vs. 2.906 years, p=0.023).

Conclusion:
Longer DAT is associated with AF inducibility post-PVI despite successful ablation. This association may reflect the increased persistence of AF as it progresses over time. Future studies are needed to evaluate the clinical implications of DAT times.