Women have less progression of paroxysmal atrial fibrillation: data from the RACE V study

Background Sex differences in atrial fibrillation (AF) are observed in terms of comorbidities, symptoms, therapies received, AF progression and cardiovascular complications.Methods We assessed the differences in prevalence and the determinants of AF progression, as well as the clinical characteristics and quality of life (QoL), between women and men with paroxysmal AF included in the RACE V (Reappraisal of Atrial Fibrillation: Interaction between hyperCoagulability, Electrical remodeling, and Vascular Destabilisation in the Progression of AF) study. At baseline, extensive phenotyping was done. To assess AF progression, implantable loop recorder (ILR) monitoring was used throughout follow-up. AF progression was defined as (1) progression to persistent or permanent AF or (2) progression of paroxysmal AF (>3% burden increase).Results 417 patients were included, 179 (43%) of whom were women. Women were older (median 67 years vs 63 years, p<0.001), less often had coronary artery disease (n=11 (6%) vs n=36 (16%), p=0.003), had more obesity (n=57 (32%) vs n=50 (21%), p=0.013), had less epicardial and pericardial fat (median 144 (interquartile range [IQR] 94-191) mL vs 199 (IQR 146-248) mL, p<0.001; and median 89 (ICQ 61-121) mL vs 105 (IQR 83-133) mL, p<0.001, respectively) and had more impaired left atrial function. The median follow-up was 2.2 (1.6-2.8) years. 51 of 417 patients (5.5% per year) showed AF progression (15/179 (8.4%) women and 36/238 (15.1%) men, p=0.032). Multivariable analysis showed tissue factor pathway inhibitor, N-terminal prohormone brain natriuretic peptide (NT-proBNP) and PR interval being associated with AF progression in women and factor XIIa:C1 esterase, NT-proBNP and proprotein convertase subtilisin/kexin type 9 in men. QoL was not different between sexes.Conclusion Despite older age, the incidence of AF progression was lower in women. Parameters associated with AF progression varied in part between sexes, suggesting different underlying pathophysiological mechanisms.