Left Atrial Strain in Pediatric Cardiology: Evidence to Date and Future Directions

Background: The function of the left atrium is a key component in the regulation of ventricular (LV) filling. Early detection of atrial dysfunction, utilizing left atrial strain (LAS), is increasingly recognized as a sensitive marker of subtle atrial dysfunction and diastolic abnormalities in pediatric cardiac conditions. Despite its availability, the clinical utility of LAS in pediatric populations remains limited, and variability in analysis methods may limit broader adoption. This review examines current literature on pediatric LAS, its clinical applications, and highlights key knowledge gaps. Methods : PubMed search using terms “pediatric”, “child”, or “adolescent” and “left atrial strain” or “LA strain” identified 107 studies. Of these, 57 original research articles published between 2015-2024 involving LAS in patients <21 years were included. LAS was assessed across three phases: reservoir (LASr), conduit (LAScd), and contraction (LASct), with attention to measurement methods (R- vs P-wave reference and single vs biplane analysis). Results: LAS was assessed in 3343 pediatric patients with cardiac disorders and 2089 healthy controls. Healthy children demonstrated higher LAS, particularly LAScd, compared to neonates and adults. Reduced LAS was reported in congenital heart diseases, linked to worse outcomes across single ventricle palliation stages. In cardiomyopathy, LAS declined with worsening diastolic dysfunction. In heart transplant recipients, LAS correlated more strongly with LV end-diastolic pressure than conventional non-invasive metrics. LAS also predicted myocardial injury in MIS-C, ischemic risks in diabetes, and early LV dysfunction from chemotherapy. A total of 38 studies (66%) reported using R-wave reference (4015 subjects) and 34 studies (59%) used single apical-four-chamber analysis (3226 subjects). Conclusions: LAS shows promise as a marker of diastolic function in the surveillance and outcomes monitoring across various pediatric cardiac disorders. However, variability in acquisition and analysis methods highlights the need for standardization. Large, prospective studies utilizing standardized methods are needed to validate LAS and define its role in clinical practice.