Impact of atrial fibrillation burden on early mitral valve remodeling in patients without significant mitral regurgitation

Background The progression of mitral valve (MV) remodeling in atrial fibrillation (AF) patients without significant mitral regurgitation (MR) remains poorly characterized. This study investigates the differential impact of AF burden (paroxysmal vs. persistent) on early MV structural and functional changes using 3D transesophageal echocardiography. Methods In this prospective cohort, 46 AF patients without significant MR (paroxysmal AF: n=18; persistent AF: n=28) underwent comprehensive 3D transesophageal echocardiography. Annular dimensions, geometry, shape, leaflet morphology, and functional parameters were quantified and statistically compared between groups.. Results Patients with persistent AF exhibited significant early mitral annular remodeling compared to paroxysmal AF, despite comparable baseline age, BMI, and BSA. The persistent AF group had significantly larger left atrial diameter (45.4 ± 7.13 mm vs. 40.3 ± 6.26 mm, p=0.05), lower left ventricular ejection fraction (45.5 ± 15.4 vs. 56.5 ± 15.2, p=0.042), and larger LV end-systolic dimension (41.3 ± 9.65 mm vs. 33.1 ± 9.35 mm, p=0.018). Quantitative 3D analysis revealed persistent AF was associated with significantly larger annular dimensions, including anteroposterior diameter (3.92 ± 0.53 mm vs. 3.60 ± 0.47 mm; p=0.042), AL-PM diameter (3.74 ± 0.50 mm vs. 3.49 ± 0.34 mm; p=0.048), 3D saddle-shaped annulus area (11.98 ± 3.19 cm² vs. 10.34 ± 2.05 cm²; p=0.038), and 2D D-shaped annulus area (9.78 ± 2.83 cm² vs. 8.27 ± 1.87 cm²; p=0.035). Perimeter measurements for both 3D saddle-shaped (12.74 ± 1.56 mm vs. 11.94 ± 1.14 mm; p=0.05) and 2D D-shaped (11.51 ± 1.47 mm vs. 10.69 ± 1.15 mm; p=0.042) annuli were also significantly larger. Leaflet morphology changes included significantly larger anterior leaflet area (8.93 ± 2.07 cm² vs. 7.60 ± 2.02 cm²; p=0.036) and smaller distal anterior leaflet angle (16.97 ± 5.03° vs. 20.76 ± 6.40°; p=0.042) in persistent AF. Functional parameters (tenting volume/area, coaptation depth) and dynamic annular motion showed no statistically significant differences. Conclusion Persistent AF is associated with adverse early mitral annular and leaflet remodeling, independent of significant MR and alongside worse LV systolic function and larger LA size. This remodeling may predispose to future MR progression, underscoring the importance of rhythm control strategies to mitigate structural changes in high-burden AF populations.