Supplementary Material for: Association between Mitral Valve Mean Pressure Gradient and Atrial Fibrillation in Patients with Rheumatic Mitral Stenosis: A Cross-sectional Study

Introduction: Atrial fibrillation (AF) often occurs in patients with rheumatic mitral stenosis (RMS) and is associated with adverse clinical outcomes. Mitral valve mean pressure gradient (MVMPG) is utilized as an indicator to assess the severity of mitral stenosis and its hemodynamic implications. This study aims to investigate the association between MVMPG and AF in individuals with RMS. Methods: We conducted a retrospective analysis of medical records from 360 consecutive patients diagnosed with RMS at the First Affiliated Hospital of Wenzhou Medical University between January 2018 and January 2023. Using both univariate and multivariate logistic regression models, the relationship between MVMPG and AF was evaluated. Restricted cubic splines were employed to test for linearity, and stratified and interaction analyses were performed to evaluate the stability of this relationship among different subgroups. Results: Based on the MVMPG levels, 360 RMS patients in total were categorized into three groups for the analysis: Q1 (10 mmHg). The average age was 60.6 years (Q1: 66.1, Q2: 61.9, Q3: 55.8), and 70.8% were female. The prevalence of AF was 39.6%, 56.5%, and 63.2% in Q1, Q2, and Q3, respectively. After adjusting for potential confounders, a significant association between MVMPG and AF was observed. In Q2, there was a 119% increase in AF (OR 2.19, 95% CI: 1.01–4.75), while in Q3, there was a 238% increase (OR 3.38, 95% CI: 1.39–8.19), compared to Q1. The relationship between MVMPG and AF was linear (p = 0.503). These results remained consistent in each subgroup analysis. Conclusion: Our study reveals a significant positive association between MVMPG and AF in patients with RMS, which holds important clinical implications. It is necessary to conduct further research.