Pediatric Heart Network Echo Z Scores

Study Questions:

What are the Z scores in the pediatric population for common echocardiographic measurements adjusted for body surface area (BSA) and stratified by age, sex, race, and ethnicity?


Echocardiogram data from 19 centers participating in the Pediatric Heart Network were collected from normal echocardiograms from nonobese healthy children ≤18 years of age. Measurements were performed at a Core Laboratory. Demographic data included age, sex, race, and ethnicity. Z score models involved indexed parameters that were normally distributed without residual dependence on BSA. The models were tested for the effects of age, sex, race, and ethnicity. A <5% difference was considered clinically insignificant because interobserver variability for echocardiographic measurements are reported as ≥5% difference.


Of 3,566 subjects, 90% had measurable images. Although multivariable regression demonstrated statistically significant impact of age, sex, race, and ethnicity for all outcomes, all effects were clinically insignificant. Z scores were therefore independent of age, sex, race, and ethnicity for each measurement.


Echocardiographic Z scores based on BSA were derived from a large, diverse, nonobese, and healthy North American population. Age, sex, race, and ethnicity have a small but statistically significant impact on scores, which is not clinically important.


This report from the Pediatric Heart Network puts forth a new set of normal reference values for pediatric echocardiography based on BSA. An important contribution of this project is that age, sex, race, and ethnicity do not have a clinically important impact on Z scores. There is the potential for wide application of this system, specifically in North America, where it was developed. The regression equations and a Z score calculator will ultimately be available on the Pediatric Heart Network website (

Keywords: AHA17, AHA Annual Scientific Sessions, Body Surface Area, Diagnostic Imaging, Echocardiography, Ethnic Groups, Heart Defects, Congenital, Nomograms, North America, Pediatrics

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