Moderate-to-Vigorous Intensity Physical Activity and Risk of Incident Atrial Fibrillation in Atrial Cardiomyopathy.

BACKGROUND

Current guidelines recommend physical activity for atrial fibrillation (AF) prevention, yet its role in individuals with atrial cardiomyopathy (AtCM) remains unclear.

OBJECTIVES

We investigated the association between accelerometer-measured moderate-to-vigorous intensity physical activity (MVPA) and incident AF according to AtCM status.

METHODS

Among 10,003 UK Biobank participants, AtCM was identified via multimodal approach integrating cardiovascular magnetic resonance imaging and 12-lead electrocardiography. Multivariable adjusted Cox proportional hazards models assessed the association between 7-day accelerometer-measured MVPA and incident AF. An interaction term evaluated substrate-specific associations.

RESULTS

AtCM was identified in 4.5% of participants. Over a median follow-up of 3.2 years, AtCM was associated with an increased risk of AF (HR: 3.01; 95% CI: 1.69 to 5.37). AtCM status significantly modified the MVPA-AF association (P for interaction = 0.029). Without AtCM, MVPA showed marginal risk reduction (HR per 10-minute increase: 0.94; 95% CI: 0.87-1.01). Conversely, with AtCM, MVPA was strongly associated with a lower AF risk (HR per 10-minute increase: 0.76; 95% CI: 0.62-0.93). The absolute risk reduction was 2.82 AF events per 1,000 person-years for every 10-minute increase in MVPA in the AtCM group, significantly greater than without AtCM (difference: -2.66; 95% CI: -4.32 to -0.73; P = 0.011). Findings remained robust across comprehensive sensitivity analyses.

CONCLUSIONS

MVPA demonstrated a robust inverse association with incident AF risk, particularly in individuals with AtCM. Identifying subclinical atrial substrate may guide targeted physical activity recommendations, suggesting MVPA as a potent lifestyle intervention to attenuate the transition from subclinical remodeling to overt clinical arrhythmia.