Impact of patient phenotype on the relationship between accelerometer-derived physical activity and cardiovascular events in atrial fibrillation

Aims Atrial fibrillation (AF) is a heterogeneous condition with varying comorbidity profiles, yet current physical activity guidelines do not differentiate between AF phenotypes. We examined the association between objectively measured moderate-to-vigorous physical activity (MVPA) and major adverse cardiovascular events (MACE) across different AF phenotypes. Methods In a prospective cohort of 4858 adults with AF (mean age 63, 37 % female) from the UK Biobank, wrist-worn accelerometry quantified MVPA. Hierarchical clustering classified individuals into 'high' and 'low' risk clusters based on comorbidities. Activity patterns were also described by rhythm control treatment status. Cox-proportional hazards models assessed the association between MVPA and MACE across clusters, while Poisson regression identified notable MVPA thresholds. Results The 'high-risk' cluster (n = 2583) experienced more MACE (HR: 3.81, 95 %CI: 3.19–4.55, p < 0.001) than the 'low-risk' cluster (n = 2275). Greater MVPA was associated with lower MACE incidence in both clusters. In the 'low risk' cluster, those with median MVPA of 187 min/week had lower MACE incidence (HR 0.39, 95 %CI 0.22–0.70, p = 0.001) than the reference group (median 56 min/week). In the 'high risk' cluster, those with median MVPA of 167 min/week had lower MACE incidence (HR 0.57, 95 %CI 0.44–0.74, p < 0.001) than their reference group (median 42 min/week). Poisson models identified 35 and 103 min/week as notable thresholds (IRRs: 0.35 and 0.31, respectively; both p < 0.001). Among patients undergoing rhythm control (n = 1354), higher MVPA was associated with lower MACE incidence (HR 0.42, 95 %CI 0.26–0.66, p < 0.001). Conclusion In this AF cohort, higher MVPA was associated with lower MACE incidence across different risk phenotypes and treatment statuses.