Left Atrial Reservoir Strain in Cardiovascular and Systemic Disease: Advances and Clinical Applications From Physiology to Practice

Traditional parameters, such as left atrial size or volume, typically reflect chronic pressure and volume overload; however, these abnormalities only become evident at advanced stages, often missing early signs of dysfunction. In contrast, left atrial reservoir strain (LASr), measured by speckle-tracking echocardiography, offers a sensitive and dynamic assessment of atrial mechanics, integrating atrial compliance with left ventricular diastolic interaction. Moreover, impaired LASr reflects atrial stiffness and fibrosis, and correlates with elevated filling pressures, making the LASr parameter a comprehensive biomarker of left-sided cardiac function. Indeed, LASr has demonstrated diagnostic and prognostic value across a wide spectrum of conditions. In heart failure with preserved ejection fraction, LASr refines the assessment of diastolic dysfunction and predicts hospitalization and mortality. In atrial fibrillation, reduced strain correlates with atrial fibrosis and left atrial appendage dysfunction, identifying patients at increased risk of arrhythmia recurrence and thromboembolism. In valvular disease, LASr uncovers subclinical remodeling and stratifies risk even in patients with apparently moderate aortic stenosis. Meanwhile, in addition to cardiovascular disease, LASr can detect early atrial impairment in systemic disorders such as hypertension, diabetes, obesity, and amyloidosis, often before structural enlargement becomes evident. Our group has shown that LASr predicts persistent hypertension after gestational hypertensive disorders, reveals subclinical diastolic dysfunction in idiopathic pulmonary fibrosis, non-invasively predicts left atrial appendage thrombus in atrial fibrillation, stratifies outcomes in moderate aortic stenosis, and provides prognostic information in acute ischemic stroke. This narrative review outlines the physiological basis, technical considerations, and clinical applications of LASr, discusses its limitations and future perspectives—including multimodality imaging and artificial intelligence—and underscores its transition from a research metric to a dynamic biomarker ready for clinical practice.