Test-retest variability of volumetric right ventricular measurements using real-time three-dimensional echocardiography

Background: Substantial variability in sequential echocardiographic right ventricular (RV) quantification may exist. Interobserver and intraobserver values are well known, but acquisition (test-retest) variability has been rarely assessed. The objective of this study was to determine the test-retest variability of sequential RV volume and ejection fraction (EF) measurements by real-time three-dimensional echocardiography in patients with congenital heart disease and healthy controls. Methods: Twenty-eight participants (21 patients with congenital heart disease, seven healthy controls; mean age, 30 ± 14 years; 43% men) underwent a series of three echocardiographic studies. To obtain interobserver and intraobserver test-retest variability, two sonographers acquired sequential RV data sets in each participant during one outpatient visit. RV volumetric quantification was done using semiautomated three-dimensional border detection. The variability data were analyzed using correlation coefficients, Bland-Altman analysis, and coefficients of variation. Results: Absolute mean differences for sequential intraobserver acquisitions were 12 ± 12 mL for end-diastolic volume, 7 ± 6 mL for end-systolic volume, and 4 ± 3% for EF. Interobserver and intraobserver test-retest variability, respectively, were 7% and 7% for RV end-diastolic volume, 14% and 7% for end-systolic volume, and 8% and 6% for EF. Conclusions: Good test-retest variability, besides the practical nature of real-time three-dimensional echocardiography for RV volume and EF assessment, makes it a valuable technique for serial follow-up. Although it may be challenging to diminish all factors that can influence echocardiographic examination for serial follow-up, standardization of RV size and functional measurements should be a goal to produce more interchangeable data.