Left Atrial Fractional Shortening: A Simple and Practical "Strain" for Everyone.

Background: The function of the left atrium (LA) is reduced in many cardiac diseases even with normal size. The assessment of its compliance could represent an added value in an echocardiographic report in case the gold standard technique (speckle-tracking echocardiography [STE]) is not available. We sought to test a simple and quick method as surrogate of STE: the dynamic measurement of the LA anteroposterior diameter (APD) that we called LA fractional shortening (LAFS).

Materials And Methods: A total of 153 consecutive patients underwent a transthoracic echocardiography in our echo laboratory between January and June 2017. The only inclusion criteria were the presence of an acoustic window and the informed consent. We chose to not apply exclusion criteria to assess LAFS feasibility. The LAFS was calculated as (maxAPD-minAPD)/(maxAPD) × 100 in parasternal long-axis view. We evaluated the correlation of its value with the peak atrial longitudinal strain (PALS) and the LA emptying fraction (EF).

Results: Mean execution time was 32.1 ± 5 s for LAFS, 2.3 ± 0.7 min for LAEF, and 2 ± 1 min for PALS. LAFS, with a feasibility of about 97%, was moderately correlated with PALS and LAEF (R between 0.20 and 0.30, < 0.05). LAFS fractional shortening also emerged as surrogate for PALS via the relationship PALS = 21.07 + 0.364x (LAFS).

Conclusions: LAFS demonstrated a correlation with PALS, a short execution time, a high feasibility, and the possibility to be used as a surrogate of PALS, applying a specific formula.