Sex differences in atrial remodeling and atrial fibrillation recurrence after catheter ablation.

Background: Women undergoing catheter ablation (CA) for atrial fibrillation (AF) reportedly have higher recurrence rates despite being generally less prone to developing AF. It remains unclear whether these sex differences are primarily driven by intrinsic disparities in atrial remodeling or by a greater burden of comorbidities.

Objectives: The purpose of this study was to evaluate sex-specific differences in AF recurrence after CA, identify modifiers of the prognostic effect of sex, and evaluate atrial remodeling using new echocardiographic parameters.

Methods: We retrospectively included patients undergoing first-time CA for AF. AF recurrence rates after an 8-week blanking period were compared between sexes. Baseline echocardiographic parameters of left atrial (LA) structure and function were assessed using volumetric and deformational indices and compared between sexes after propensity score (PS) matching.

Results: The study included 560 patients (35% women) with a median follow-up of 19 months. Women were older (64 years vs 58 years; P<.001) and had more comorbidities than men. Women also exhibited a higher incidence of AF recurrence, both after adjusting for confounders (hazard ratio 1.75; 95% confidence interval 1.21-2.53) and after PS matching (hazard ratio 1.73; 95% confidence interval 1.05-2.87). Baseline characteristics did not modify the prognostic effect of sex on AF recurrence. In the PS-matched cohort of 113 patient pairs, women showed lower LA strain, increased LA stiffness, and more low-voltage areas, despite similar LA dimensions.

Conclusion: Female sex was an independent predictor of AF recurrence. After adjusting for confounders, women showed decreased LA strain and higher stiffness, suggesting intrinsic disparities in atrial remodeling that may explain their higher recurrence rates.