Poor rhythm outcome of catheter ablation for early-onset atrial fibrillation in Women ― Mechanistic insigh

Background: Catheter ablation is a good treatment option for atrial fibrillation (AF) in young symptomatic patients. However, there is little information on the efficacy of catheter ablation of early-onset AF between sexes. Methods and Results: This study included 1,060 patients under the age 60 years old (837 men, 49.8±7.7 years old, 70.8% paroxysmal AF) who underwent catheter ablation for AF. Sex differences in clinical presentation and ablation outcomes were compared with and without propensity score-matching. During 24.5±18.9 months of follow-up, women showed significantly higher clinical recurrence of AF than men (log-rank, P=0.002). Female sex was independently associated with post-ablation clinical recurrence of AF (adjusted hazard ratio (HR) 2.58 [1.06–6.30], P=0.037). Women had a higher proportion of left ventricular diastolic dysfunction (E/Em, P<0.001), higher prevalence of heart failure (P=0.017), greater left atrial (LA) volume index (P=0.001), lower LA endocardial voltage (P<0.001), and higher parasympathetic nervous activity (root-mean square of differences, P<0.001; high-frequency (HF), P=0.010) than men. After a second ablation procedure (n=111), women still showed a higher clinical recurrence rate than men (log-rank, P=0.003) during 22.9±15.0 months of follow-up. Conclusions: Among patients with early-onset AF who underwent catheter ablation, women showed poorer clinical outcomes than men after de novo and second procedures. Left ventricular dysfunction, LA remodeling, and autonomic nervous function may be potential mechanisms underlying sex differences in catheter ablation outcomes of early-onset AF.