<p>Atrial fibrillation and heart failure frequently coexist and interact through shared pathophysiological mechanisms, each condition promoting the onset and progression of the other. This bidirectional relationship is mediated by structural and electrical remodelling, neurohormonal activation, and atrial myocardial disease, resulting in worse clinical outcomes compared with either condition alone. Advances in heart failure–directed medical therapy, rhythm-control strategies—particularly catheter ablation—and device-based monitoring have reshaped contemporary management, while recent trials have challenged traditional approaches to anticoagulation in patients with subclinical atrial arrhythmias. This review synthesizes current evidence on the mechanisms linking atrial fibrillation and heart failure, discusses evolving therapeutic strategies including early rhythm control and device-detected atrial high-rate episodes, and highlights areas of uncertainty and future research. An integrated, patient-centered approach addressing both arrhythmia burden and heart failure substrate is essential to improving outcomes in this complex and growing population.</p> Graphical abstract <p></p>