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

Left atrial strain (LAS) is a sensitive marker of early atrial dysfunction and left ventricular diastolic abnormalities in pediatric heart disease, yet clinical integration remains limited. Evidence from 57 studies (2015-2024) including >5,300 patients <21 years of age demonstrates that healthy pediatric patients have higher LAS values, particularly left atrial conduit strain, than neonates and adults. Reduced left atrial reservoir and conduit strain is consistently reported in congenital heart disease and is associated with adverse outcomes across single-ventricle palliation stages. In pediatric cardiomyopathy, LAS impairment parallels worsening diastolic function. Among heart transplant recipients, left atrial reservoir strain correlates more strongly with invasive filling pressures than conventional noninvasive metrics. LAS also predicts myocardial injury in multisystem inflammatory syndrome in children, ischemic risk in diabetes, and early left ventricular dysfunction from chemotherapy. Despite its potential for diastolic function assessment, variability in acquisition and analysis remains substantial. Standardized protocols and larger prospective studies are needed to establish normative values and define clinical thresholds.