Structural and functional predictors of atrial functional mitral regurgitation in patients with atrial fibrillation and its impact on efficacy of pulmonary vein isolation

Background Atrial fibrillation (AF) is frequently accompanied by atrial functional mitral regurgitation (AFMR), reflecting atrial remodeling. Determinants of AFMR and its impact on pulmonary vein isolation (PVI) efficacy remain incompletely understood. Purpose To identify structural and functional determinants of AFMR in AF patients and evaluate its impact on long-term PVI outcomes. Methods We prospectively enrolled 121 patients (female/male: 39.7%/60.3%; mean age 64.9 ± 9.5 years; body mass index [BMI] 29.4 ± 4 kg/m²) with symptomatic AF (European Heart Rhythm Association [EHRA] class 2b–3; CHA2DS2-VA score 2.1 ± 1.3), including paroxysmal (71.1%) and persistent (28.9%) AF undergoing PVI. Baseline AFMR, echocardiographic parameters, and biomarkers (Nterminal pro-B-type natriuretic peptide [NT-proBNP], galectin-3, insulin-like growth factor-binding protein-7 [IGFBP-7], copeptin) were assessed. Twelve-month follow-up included clinical evaluation, echocardiography, and 72-hour Holter monitoring. Logistic regression identified predictors of AFMR and PVI success. Results AFMR was present in 86 patients (71.1%). Compared with AFMR(−), AFMR(+) patients had larger left atrial (LA) area (23.5 ± 4.7 vs 20.8 ± 4.0 cm²; p=0.003), greater mitral annular diameter (34.9 ± 3.4 vs 33.3 ± 3.4 mm; p=0.034), more frequent left ventricular (LV) diastolic dysfunction (33.7% vs 12.5%; p=0.049), and higher galectin-3 and IGFBP-7 levels (p=0.025). Independent predictors of AFMR were older age (odds ratio [OR] 1.07; p=0.028) and larger LA size (OR 1.22; p<0.001), while male sex was a protective factor (OR 0.17; p=0.013). Due to incomplete follow-up, efficacy was assessed in 79 patients with 12-month data. Successful PVI was achieved in 71 (89.9%). Baseline AFMR did not influence PVI efficacy and was present in 53 (74.65%) patients with successful and 7 (87.5%) with unsuccessful PVI (p=0.480). Successful PVI was associated with smaller LA dimensions (p≤0.032), smaller mitral annulus (p=0.024), higher left ventricular ejection fraction (LVEF; p=0.046), and greater LV global longitudinal strain (GLS) (−20.2 ± 2.1 vs −16.6 ± 3.1; p=0.002). In multivariable analysis, smaller LA size (OR 0.707; p=0.042), higher LV GLS magnitude (OR 0.461; p=0.007), and lower NT-proBNP (OR 0.998; p=0.028) predicted long-term PVI success. Maintenance of sinus rhythm reduced AFMR prevalence (74.7% to 32.4%), NT-proBNP (739.1 ± 687.6 to 247.8 ± 289.9 ng/L; p=0.001) and copeptin levels (168.3 ± 50.7 to 121.5 ± 86.2 pg/mL; p=0.016), with atrial and ventricular reverse remodeling. Conclusions AFMR is highly prevalent in AF patients referred for PVI and reflects atrial remodeling. Although baseline AFMR does not impair procedural efficacy, long-term PVI success is determined by left atrial remodeling and subclinical LV dysfunction. Restoration of sinus rhythm is associated with AFMR reduction and significant reverse cardiac remodeling