The left atrium in heart failure with preserved ejection fraction: What we know and what we do not know

Heart failure with preserved ejection fraction (HFpEF) is a complex and heterogeneous condition with a distinct pathophysiology involving both systemic and cardiac dysfunction. Its impact extends beyond the left ventricle, notably to the atrial chambers where atrial abnormalities manifesting with structural, functional, and electrophysiologic abnormalities demonstrate a bidirectional relationship with impaired ventricular filling. These atrial changes create a pro-arrhythmic substrate, fostering both initiation and perpetuation of atrial fibrillation. Conversely, atrial disease, including atrial fibrillation, exacerbates HFpEF by promoting further pathologic remodeling, aggravating diastolic dysfunction, and elevating filling pressures. This bidirectional interaction establishes a mutually reinforcing feedback loop, which is associated with increased morbidity and mortality. In this review, we will highlight key aspects of atrial cardiomyopathy associated with HFpEF and explore their impact on HFpEF pathophysiology and treatment.