Size and Function of the Right Atrium in Healthy Children by Three-Dimensional Echocardiography

Area of Science:

• Pediatric Cardiology
• Echocardiography
• Cardiac Imaging

Background:

• Right atrial volume and function are crucial prognostic indicators in cardiac disease.
• Three-dimensional echocardiography (3DE) offers enhanced accuracy for assessing right atrial (RA) parameters.
• Established normal reference values for pediatric RA volume and function using 3DE are lacking.

Purpose of the Study:

• To establish normal reference values for 3DE-derived right atrial volume (RAV) and function in healthy children.
• To compare different regression methods (body surface area, height, weight, sex) for indexing these pediatric RA measurements.
• To compare 3DE-derived values with those obtained from two-dimensional echocardiography (2DE).

Main Methods:

• Retrospective analysis of 187 3DE datasets from healthy children across two international centers.
• Measurement of 3DE volumes using vendor-agnostic software and 2DE end-diastolic volume (EDV) via the area-length method.
• Exploration of regression curve-fitting for height, weight, BSA, and sex to optimize homoscedasticity and correlation.

Main Results:

• Indexing 3DE RAV to BSA alone resulted in heteroscedasticity.
• Optimal homoscedastic regression was achieved using a model incorporating height, weight, and sex.
• Total RA emptying fraction showed no age or sex variation, while active and passive emptying were best described by a spline curve.
• Strong agreement was observed between 3DE and 2DE derived EDV (r² = 0.83).

Conclusions:

• This study provides essential reference values for pediatric RA size and function assessed by 3DE.
• A superior method for indexing pediatric RA measurements, beyond BSA alone, has been identified.
• The findings facilitate more accurate prognostic assessments in pediatric cardiac disease.