Inhomogeneity of the Left Atrial Strain

Background and Objectives: Left atrial function is commonly assessed using speckle-tracking echocardiography, focusing on global strain averaged from the 4-chamber and 2-chamber views. However, regional variations in atrial strain remain underexplored. This study aimed to evaluate regional left atrial deformation in healthy subjects. Materials and Methods: A total of 22 healthy subjects underwent echocardiographic examinations during routine check-ups in 2023-2024. Images were retrieved and analyzed offline. Left atrial reservoir strain was calculated from four-chamber, two-chamber, and three-chamber views. A comprehensive map of 3-plane strain was generated for each patient, with detailed analysis of regional strain differences. Regional and average longitudinal displacement were also assessed. Results: There was no significant difference between triplane and biplane left atrial reservoir strain (34.4 ± 7.7% vs. 34.7 ± 6.8%, p = 0.9). Strain in the segments near the mitral annulus was significantly higher than in the mid-atrial segments. Mid-atrial strain was, in turn, higher than in the superior segments. Regional longitudinal displacement showed a gradient from the mitral annulus toward the superior part of the atrium, correlating well with the strain results. Additionally, strain in the inferior and septal walls was higher than in the lateral wall. Conclusions: Left atrial strain varies significantly across different regions. Strain is highest near the mitral annulus and lowest in the superior wall. Longitudinal displacement may serve as an additional tool for assessing left atrial function, showing a strong correlation with strain measurements. Biplane and triplane strain assessment yielded comparable results.