Serum Thiol/Disulfide Homeostasis as a Marker of Left Atrial Remodeling in Atrial Fibrillation

Objective: Oxidative stress has been implicated in the pathogenesis of atrial fibrillation (AF), contributing to atrial remodeling through redox imbalance. This study aimed to evaluate the relationship between serum thiol/disulfide homeostasis (TDH) parameters and echocardiographic indices of left atrial (LA) structural remodeling in patients with AF.
Method: This cross-sectional study included 123 patients diagnosed with AF and 58 healthy controls. Demographic, biochemical, and echocardiographic data were collected for all participants. Serum native thiol, total thiol, and disulfide levels were analyzed using a fully automated spectrophotometric method. LA dimensions, volume, sphericity, and volume index were measured via transthoracic echocardiography. Correlation and multiple linear regression analyses were performed to identify factors independently associated with LA volume index.
Results: Patients with AF exhibited significantly increased LA diameters, LA volume, and LA volume index compared with controls (all p < 0.001). TDH parameters did not differ significantly between the AF and control groups (p > 0.05). Within the AF cohort, native thiol and total thiol levels were inversely correlated with LA longitudinal diameter and LA dimension index, respectively. In multivariate analysis, native thiol level (β = –0.235, p = 0.001), body surface area (β = –0.143, p = 0.03), and AF duration (β = 0.659, p < 0.001) independently predicted LA volume index.
Conclusion: Native thiol levels showed a modest association with indices of left atrial remodeling in AF. Given the absence of between-group differences and the relatively weak correlations, these findings should be interpreted as hypothesis-generating rather than definitive.

Keywords: Atrial fibrillation, echocardiography, left atrial remodeling, oxidative stress