Atrial Fibrillation Pattern and Outcomes After Contemporary Left Atrial Appendage Occlusion

Background Atrial fibrillation (AF) pattern predicts thromboembolic risk during anticoagulation, but its prognostic importance after left atrial appendage occlusion (LAAO) is uncertain. Objectives To determine whether AF pattern independently predicts residual clinical risk after contemporary LAAO and whether peri-device leak (PDL) or device-related thrombus (DRT) identify a persistently high-risk subgroup. Methods We studied 3,459 patients with documented AF pattern undergoing LAAO in a contemporary multicenter registry. AF was classified as paroxysmal, persistent or long-standing persistent, or permanent. The primary endpoint was a 2-year hierarchical composite of death, stroke or systemic embolism (stroke/SE), and major bleeding analyzed by win ratio. Inverse probability weighting and propensity score methods adjusted for baseline differences. Follow-up imaging assessed PDL and DRT. Results After inverse probability weighting, persistent and permanent AF were associated with progressively worse hierarchical outcomes compared with paroxysmal AF (win ratios 1.39 and 1.59, respectively). Non-paroxysmal AF was associated with higher stroke risk (HR 1.64; 95% CI 1.07–2.50), without increased mortality or major bleeding. PDL and DRT were more frequent in non-paroxysmal AF. In the PDL/DRT subgroup, non-paroxysmal AF was associated with higher first stroke/SE risk (HR 1.83; 95% CI 1.00–3.34), concentrated 180–540 days after LAAO. Conclusions AF pattern independently stratified residual clinical risk after LAAO, with progressively worse severity-weighted outcomes from paroxysmal to persistent and permanent AF. Excess risk was driven primarily by thromboembolism. In the PDL/DRT subgroup, the association was concentrated 180–540 days after LAAO, suggesting these patients may benefit from prolonged thromboembolic surveillance.