Understanding atrial failure: from diagnosis to clinical implications.

Atrial failure is an emerging clinical syndrome that results from an underlying atrial cardiomyopathy and is characterized by impaired atrial haemodynamic and/or electrical function that is sufficient to cause symptoms, adverse clinical outcomes or both. Similar to ventricular cardiomyopathy, atrial cardiomyopathy refers to a structural, functional and/or electrophysiological tissue abnormality, whereas atrial failure denotes the stage at which it manifests clinically. Atrial failure can be classified as primary, when driven by intrinsic atrial pathology, or secondary, when atrial dysfunction arises from sustained haemodynamic or electrical stress imposed by ventricular, valvular or systemic disease. Increasing evidence indicates that atrial failure might not be merely a bystander, but a key determinant of symptoms and prognosis in cardiovascular conditions. Atrial failure can act as a primary driver of heart failure with preserved ejection fraction, promote atrial arrhythmias through adverse electrical remodelling, and potentially increase thromboembolic risk independently of atrial fibrillation. In this Review, we detail the pathophysiological mechanisms and clinical phenotypes of atrial failure and highlight the role of multimodality imaging in diagnosing and phenotyping atrial cardiomyopathy and clinical atrial failure. Finally, we summarize emerging therapeutic strategies aimed at potentially reversing atrial adverse remodelling and discuss future directions for integrating atrial failure into clinical practice.