Pediatric ranges of normality for 2D speckle-tracking echocardiography atrial strain: differences between p- and r-gating and among new (Atrial Designed) and conventional (Ventricular Specific) software's.

Background: 2D speckle tracking echocardiography (STE) atrial strain (ε) analysis in children is gaining interest; however, pediatric nomograms remain limited. Comparison among conventional software's (designed for left ventricle and adapted to atria and using R-gating analysis) and new software's (designed for atria and allowing for both R- and P-gating) are lacking. The present study aims to establish pediatric nomograms for atrial ε using an atrial dedicated software and to compare values obtained by (a) R- and P-gating and, (b) R-gating with new and conventional software.

Methods: Echocardiographic measurements included STE left (LA) and right (RA) atrial longitudinal reservoir, conduit and contractile ε. Age/weigh/height/heart rate, and body surface area (BSA) were used as independent variables in the statistical analysis.

Results: In all, 580 healthy subjects (age range, 31 days-18 years; mean age 7.5 years; median age 7.1 years; inter-quartile range, 4.3-10.7 months; 45.5% female) were included. Feasibility of atrial ε measurements was high (98.9-96.8%). At lower age, atrial conduit ε was lower (p<0.001) while contractile ε was higher (p<0.001). All atrial ε values calculated with P-gating method were lower-than R-gating values (p<0.001). R-gated LA ε reservoir values generated with the new software were lower, and R-gated RA contractile ε higher than with the conventional software (p<0.011).

Conclusion: We report pediatric atrial ε values from a dedicated atrial software. Maturational changes in STE atrial ε values were demonstrated. Significant differences were observed among ε values obtained with P- and R-gating and with different software's.