Sex Disparities in Atrial Fibrillation and Atrial Flutter Presentation, Treatment, and Outcomes in Reproductive‐Aged Individuals

Background Atrial fibrillation/flutter (AF/AFL) are increasingly seen in reproductive‐aged adults, yet AF/AFL guidelines are largely based on older populations. Sex differences in this age group remain poorly defined. In this study, we examined sex‐based disparities in the presentation, management, and outcomes among reproductive‐aged adults with AF/AFL. Methods Using the Get With The Guidelines–Atrial Fibrillation national registry, we included adults (18–50 years) with AF/AFL who were prospectively enrolled from May 2013 to March 2024. The primary exposure was sex and primary outcomes included anticoagulant prescription and rhythm control strategies (cardioversion, AF ablation, or antiarrhythmic therapy). Multivariable logistic regression estimated associations between sex and outcomes, adjusting for covariates including age, race and ethnicity, insurance, and anemia. Results Among 14 301 patients with mean age 42.3 ± 7.3 years, women were more symptomatic and had more paroxysmal AF (57.7% vs. 49.9%, p < 0.001), while men had more persistent AF (19.9% vs. 11.6%, p < 0.001). CHA 2 DS 2 VASc scores were significantly higher in women (2.3 ± 1.2 vs. 1.4 ± 1.2 in men, p < 0.001). Despite similar use of antiarrhythmic drugs and anticoagulation, women were 9%–15% less likely to receive rhythm‐control therapies overall (adjusted OR 0.91, 95% CI 0.83–0.99), driven by differences in AF ablation and cardioversion. For both sexes, the proportion of patients undergoing ablation increased while those undergoing cardioversion decreased significantly over time (all p < 0.001). Women undergoing AF ablation experienced more complications (3.7% vs. 1.9%, p = 0.01) and were more likely to have relative or absolute contraindications to anticoagulation (9.0% vs. 7.2%, p < 0.001). Conclusions In a large US registry, reproductive‐aged women with AF/AFL were less likely to receive rhythm‐control interventions, experienced more ablation complications, and had more anticoagulation contraindications. These findings highlight persistent sex‐based disparities in the management and outcomes of young adults with AF/AFL, underscoring the need for targeted, sex‐specific approaches to improve treatment inequities.