2D Contour: A Simplified Approach for Left Atrial Reservoir Strain

Background: Left atrial strain reservoir (LASr) has emerged as a useful parameter in assessing diastolic dysfunction and heart failure with preserved ejection fraction. LASr is typically assessed using speckle-tracking echocardiography (STE), which was developed to measure strain in the left ventricle. Despite its strength demonstrated in several clinical studies, the application of STE to the left atrium presents well-known limitations: thin walls, anatomical discontinuities, far-field location, and inter-vendor variability. The present study aims to evaluate the efficacy of an alternative method for assessing LASr, based on the percentage shortening of the atrial wall contour, by directly comparing it with STE-derived LASr values. Methods: We retrospectively analyzed 246 patients in sinus rhythm with severe organic mitral regurgitation. The 2D contour strain method quantifies changes in the length of the two-dimensional (2D) endocardial atrial wall contour between end-systolic and end-diastolic frames. The peak strain value is calculated as: (maximum perimeter length−minimum perimeter length)/maximum perimeter length × 100. Results: 2D contour strain measurements were feasible in all patients. A strong correlation was observed between STE-derived and 2D contour-derived LASr values, with an R-value of 0.93. On average, 2D contour strain measurements underestimated LA peak strain by approximately 1% compared to STE. The consistency of 2D contour LA strain measurements, as assessed by inter- and intra-observer reproducibility, was excellent. Conclusion: These findings suggest that 2D contour LA strain is a feasible and reliable alternative to STE for assessing LASr. This approach is particularly valuable in echocardiography labs where STE software for LA is unavailable.