Two-dimensional speckle-tracking echocardiography of the left atrium: feasibility and regional contraction and relaxation differences in normal subjects.

Background: Increased left atrial (LA) size and reduced global contractility are related to adverse cardiac events. The potential incremental value of assessing regional LA contractility is unknown. To assess the feasibility of measuring this variable angle, independent 2-dimensional speckle-tracking strain echocardiography (2D-SpTr) was used to measure regional LA strain (epsilon) and strain rate (SR) in normal individuals of various ages.

Methods: From standard apical views, 2D-SpTr was used on 84 normal subjects to measure longitudinal velocity, epsilon, and SR in 13 LA segmental regions. The values obtained from the different atrial regions were compared with each other and corresponding LA volumes before and after LA contraction.

Results: Regional LA epsilon and SR could be measured in 77 of 84 normal subjects (94%). A consistent pattern of differences in LA regional function was noted with the annular regions, and particularly the inferior wall having a larger average peak velocity and epsilon and SR values in comparison with the mid and superior LA segments. Peak epsilon and SR during LA contraction had only a modest correlation with LA volumes.

Conclusion: The angle-independent technique of 2D-SpTr tracking can analyze regional LA epsilon and SR in 94% of normal subjects. Regional differences in LA contractility are consistently present. The annular regions, and especially the inferior wall have the highest values for LA epsilon and SR. The significance of these findings and their possible use in identifying disease states will require further study.