Sex differences in atrial fibrillation-related atrial remodelling assessed by electroanatomic mapping and biopsy

Histopathological sex differences in atrial structural remodelling in patients with non-valvular atrial fibrillation (AF) require further investigation.

Right atrial biopsy was performed on 282 patients undergoing AF ablation and high-density voltage mapping (66 ± 12 years; 81 women). Of the 58 patients without AF undergoing supraventricular tachycardia ablation included, 26 underwent atrial biopsy and 41 underwent voltage mapping. The voltage at the biopsy site (V_biopsy), global left atrial voltage (V_GLA), and histopathological parameters (fibrosis, intercellular space, myofibrillar loss, myocardial nuclear density, and cardiomyocyte diameter) were evaluated.

V_biopsy (7.4 ± 2.6 vs 9.3 ± 3.2 mV, P < .001) and V_GLA (4.9 ± 1.8 vs 6.7 ± 2.2 mV, P < .001) were significantly lower in women with AF. A similar relationship was observed in patients without AF: V_biopsy (7.8 ± 2.7 vs 10.9 ± 2.6 mV, P < .001) and V_GLA (7.3 ± 1.7 vs 9.4 ± 1.4 mV, P < .001) were lower in women. V_biopsy and V_GLA positively correlated in both groups (r = 0.70 and 0.60, P < .001), supporting an integrated interpretation of the voltage and histopathological data. No significant sex differences were observed among the histopathological parameters. In 34 patients with minimal histological change, small cardiomyocytes (<10 μm) were more frequent in women (37% ± 23% vs 20% ± 19%, P = .029).

Despite consistently lower voltage in women, no significant histopathological sex differences were identified in non-valvular cases, likely due to their inherently smaller atrial mass.