Intervendor agreement for left atrial strain via speckle tracking echocardiography in pediatrics

Left atrial strain (LAS) is a promising tool for early detection of diastolic dysfunction in pediatric heart transplant and cardiomyopathy. However, routine use is limited by insufficient vendor agreement data. This study evaluates intervendor and intravendor agreement of LAS in pediatrics using two common echocardiography software platforms. LAS was prospectively assessed in 89 children. Left atrium (LA) focused echocardiographic images were analyzed with GE EchoPAC AFI LA at the acquired frame rate and with TomTec Autostrain (TT) at both the acquired (TTacq) and compressed frame rate of 30 frames per second (TT30). LA reservoir, conduit, and contraction strain were measured using end-diastole and atrial-contraction references. Agreement was evaluated using intraclass correlation coefficients (ICC) and Bland-Altman plots. Participants included 30 children with hypertrophic cardiomyopathy and 59 with normal echocardiograms (ages 2 months-21 years). Agreement between GE and TTacq (ICCs:0.85-0.92), GE and TT30 (ICCs:0.87-0.90), and TTacq and TT30 (ICCs:0.94-0.96) were excellent. Bland-Altman analysis showed GE absolute LAS values were lower compared to TTacq (bias - 3.99%) and TT30 (bias - 3.84%), whereas TTacq and TT30 did not show significant difference in LAS values (bias 0.15%). Higher agreement was observed in patients with cardiomyopathy, abnormal LV global longitudinal strain (GLS), and larger indexed LA volumes. LAS showed excellent agreement and reproducibility across vendors, particularly in patients with cardiomyopathy, abnormal LV GLS, and larger LA sizes. TomTec yielded 4% higher absolute LAS values compared to GE. As such, we recommend using vendor-specific normative references when interpreting borderline and abnormal LAS values.