Variability in the Echocardiographic Evaluation of the Systemic Right Ventricle

Echocardiographic evaluation of the systemic right ventricle (sRV) remains challenging in patients with transposition of the great arteries (TGA) corrected by an atrial switch (AS) and with congenitally corrected TGA (ccTGA). The aim of this study was to determine the interobserver and intraobserver variability of echocardiographic parameters for sRV size and systolic function.

Six independent observers retrospectively interpreted 44 previously acquired echocardiograms (25 patients with TGA/AS and 19 patients with ccTGA). Quantitative parameters included inlet and longitudinal diameters, systolic and diastolic areas, fractional area change (FAC), and wall thickness. sRV dilatation and systolic function were qualitatively graded as normal, mild, moderate, or severe. sRV hypertrophy was graded as present or absent. Intraclass correlation coefficients (ICCs) and Kappa statistics were computed to assess interobserver variability. Images from 10 patients (5 TGA/AS and 5 ccTGA) were reinterpreted at a 1-month interval, and ICC and Kendall tau b statistics were computed to assess intraobserver variability.

Interobserver and intraobserver agreement were good to excellent for sRV diameters, areas and FAC (ICC, 0.49-0.97), except for the sRV wall thickness (ICC < 0) and the FAC for 1 observer. Interobserver agreement was poor for the qualitative assessment of sRV size and systolic function (Kappa < 0.25), but with a good to excellent intraobserver agreement.

These findings suggest that overall appreciation of sRV size and systolic function relies on variable interpretation of measurements by observers. Readers experienced in CHD and with clear thresholds for quantitative parameters, along with a validated algorithm, are required to guide the evaluation of sRV.