Right Ventricular Outflow Tract (RVOT) Changes in Children with an Atrial Septal Defect: Focus on RVOT Velocity Time Integral, RVOT Diameter, and RVOT Systolic Excursion.

Abstract

Aim of the study was to determine the influence of right heart volume overload in children with atrial septal defect (ASD) on right ventricular outflow tract (RVOT) variables. A prospective study was conducted in 115 children (age range: 2days-18.1years) with a moderate to large ASD. We determined effects of age, body length (BL), body weight (BW), and body surface area (BSA) on the variables RVOT diameter, RVOT velocity time integral (VTI), and RVOT systolic excursion (SE), and tested the predictive value of published normal values for age, BW, BL, and BSA in our ASD patients. In our pediatric ASD patients, the age-specific RVOT diameter (z-score: +2.2, 95% CI: 2.0-2.4, P<0.001) was significantly increased compared to normal values with 54% of our ASD patients having a z-score >2.0. The age-specific RVOT VTI z-score (z-score: +3.6, 95% CI: 3.2-3.9, P<0.001) was significantly increased compared to normal values with 81% of our ASD patients having a z-score >2.0. The age-specific RVOT SE z-score was not increased but slightly lower compared to normal values (z-score: -0.5, 95% CI: -0.7 to -0.3, P<0.001) with 3% of our ASD patients having a z-score >2.0 while 12% of the patients had a z-score <-2. In our study population, we show the RVOT VTI and diameter to be relevant predictors in identifying an enlarged RVOT size and flow in children with moderate to large ASD.