The objectives of this study were:
Data were collected on 3566 healthy nonobese children ≤18 years of age with normal echocardiograms.
Body size was found to be the best predictor of the sizes of cardiovascular structures, and age, sex, and race did not have a clinically significant effect on this relationship.
The PHN z-scores are available in an online Z-score calculator.
Echocardiography (echo) is crucial for the evaluation of children with congenital and acquired heart diseases. It is the primary way to see heart structures to establish diagnoses, determine treatment options, monitor disease progression, and assess the effects of intervention. The sizes of hearts and blood vessels are frequently affected by the abnormal way that blood flows in children with malformed heart structures. Treatment decisions rely on an accurate determination of cardiovascular size, which is an important component of this echo study. Accurate, normal values must be available for clinicians to distinguish a normal finding from an abnormal one and to determine if the size of a structure is adequate, too small, or too large to function effectively.
The Z-score tells us how far above or below the score is from the mean. Similar to growth charts, they allow comparisons of cardiac measurements obtained for an individual child with measurements obtained from a normal population adjusted for the effects of body size, age, gender, and/or race.
Patients less than or equal to 18 years of age with echo images performed after January 1, 2008. Patient records must also have documented height, weight, gender, and race.
L. Lopez, Circ Cardiovasc Imaging 2017; 10(11):e006979.
Data were collected on 3566 healthy nonobese children ≤18 years of age with normal echocardiograms to produce reference values for echocardiogram measurements based on age, sex, race, ethnicity, height and weight. Body size was found to be the best predictor of the sizes of cardiovascular structures, and age, sex, and race did not have a clinically significant effect on this relationship.
E.V. Saarel, Circ Arrhythm Electrophysiol 2018 Jul;11(7):e005808.
Electrocardiography is a cornerstone in the cardiac evaluation of children. Wide variation in previously published data, much of which was obtained before the digital era, provided a strong motivation to obtain more reliable data on electrocardiogram (ECG) measurements in healthy children from North America. This study found that most ECG measurements varied by sex and race and differed from prior studies done in smaller, more racially and ethnically homogeneous populations. This study provides valuable data that can be used clinically for interpreting pediatric ECGs in the modern era for diagnosis or screening of heart disease in North America, particularly for Long QT syndrome and left ventricular hypertrophy.
P. C. Frommelt, J Am Soc Echocardiogr. 2019 Oct;32(10):1331-1338.e1.
D. Truong, Cardiol Young. 2020 Apr;30(4):456-461.
M. E. Alexander, Pediatric cardiology. 2024 Jun; 45 (5):1055-1063.
Electrocardiograms (ECGs) are a primary screening test of cardiac disease in children. They are often the first test obtained when a child sees a cardiologist, and they are obtained on apparently healthy children when looking for hidden cardiac disease. The normal standards used are a mix of older groups, groups lacking in diversity, and only a minority of those standards reference echocardiograms, which are the gold standard for cardiac anatomy and size. The Pediatric Heart Network Normal Echocardiogram Z-score Project provided a diverse group of 2170 healthy children with both ECGs and echocardiograms. We hypothesized that ECG and echocardiographic measures of left ventricular dimensions are sufficiently correlated to imply a clinically meaningful relationship. While the statistical relationship between ECG size and measured echocardiographic left ventricular size was quite strong, those correlations were weak. The majority of differences between ECGs in healthy children could not be easily explained by the size of the heart, the size of the child or the age, sex and race of the child. Thus, our data support deemphasizing the use of traditional measurement-based ECG markers as standalone indications for further cardiac evaluation in children.