Feasibility of New Transthoracic Three-Dimensional Echocardiographic Automated Software for Left Heart Chamber Quantification in Children

Abstract

New three-dimensional echocardiographic automated software (HeartModel) is now available to quantify the left heart chambers. The aims of this study were to assess the feasibility, reproducibility, and analysis time of this technique and its correlation with manual three-dimensional echocardiography (3DE) and cardiac magnetic resonance (CMR) in children. Ninety-two children (5-17years of age) were prospectively included in two separate protocols. In protocol 1, 73 healthy children underwent two-dimensional and three-dimensional transthoracic echocardiography. Left ventricular (LV) end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV ejection fraction (LVEF), and left atrial volume at ventricular end-systole (LAV) by automated 3DE were compared with the same measurements obtained using manual 3DE. In protocol 2, automated three-dimensional echocardiographic measurements from 19 children with cardiomyopathy were compared with CMR values. Automated 3DE was feasible in 77% of data sets and significantly reduced the analysis time compared with manual 3DE. In protocol 1, there were excellent correlations for LVEDV, LVESV, and LAV between automated 3DE and manual 3DE (r=0.89 to 0.99, P<.0001 for all) and a weak correlation for LVEF, despite contour adjustment (r=0.57, P<.0001). Automated 3DE overestimated LVEDV, LVEF, and LAV with small biases and underestimated LVESV with wider bias. With contour adjustment, the biases and limits of agreement were reduced (bias: LVEDV, 0.9mL; LVESV, -1.2mL; LVEF, 2.2%). In protocol 2, correlations between automated 3DE with contour edit and CMR were good for LV volumes and LAV (r=0.76 to 0.94, P<.0003 for all) but remained weak for LVEF (r=0.46, P=.05). Automated 3DE slightly underestimated LV volumes (relative bias, -7.2% to -7.8%) and significantly underestimated LAV (relative bias, -31.6%). The limits of agreement were clinically acceptable only for LVEDV. Finally, test-retest, intraobserver, and interobserver variability values were low (<12%). HeartModel is feasible, reproducible, faster than manual 3DE, and comparable with manual 3DE for measurements of LV and left atrial volumes in children >5years of age. However, compared with CMR, only LVEDV measured by automated 3DE with contour edit seems applicable for clinical practice.