BACKGROUND: Atrial fibrillation (AF) is common in patients with mitral regurgitation (MR) undergoing transcatheter edge-to-edge repair (TEER) with MitraClip, but its impact on procedural hemodynamics and clinical outcomes remains inadequately characterized. METHODS: This retrospective single-centre study analysed 226 high-risk patients who underwent MitraClip implantation between 2010 and 2022. The primary endpoint was time to first heart failure hospitalization. Secondary endpoints included procedural hemodynamics and long-term mortality. RESULTS: AF was present in 46.9% of patients and was associated with distinct hemodynamic features, including significantly elevated right (11 vs 9 mmHg, P=0.008) and left atrial pressures (17 vs 15 mmHg, P=0.023). Despite similar procedural success rates, AF patients experienced markedly accelerated time to first HF hospitalization (median 48 vs 106 weeks, P=0.005). Tricuspid regurgitation at discharge emerged as the strongest predictor of early HF hospitalization (HR 1.393, 95% CI: 1.009-1.924, P=0.044). One-year mortality (16.0% vs 16.7%, P=0.899) and long-term survival remained comparable between groups. CONCLUSIONS: AF in TEER patients is characterized by elevated atrial filling pressures and substantially accelerated time to HF hospitalization, with tricuspid regurgitation at discharge predicting early events. While these findings indicate the need for more intensive monitoring of AF patients during the first post-procedural year, comparable survival rates suggest that AF alone should not preclude TEER in otherwise suitable candidates.