1.5 3D-STE Analysis
Offline analysis of 3D-STE was conducted by an experienced cardiologist who remained blinded to the study groups. The TomTec 4D RV software (version 4.6, TomTec Image Arena) was utilized for strain analysis, a vendor-independent tool specifically designed to quantify cardiac wall motion in 3D ultrasound data, with a focus on RV functions. Using the TomTec 4D RV software, 3D RV volumetric analysis was performed. In the RV apical four-chamber and coronal views, the RV apex point and the center of the tricuspid annular line were identified. Subsequently, in the RV short-axis view, the junctions of the RV free wall with the interventricular septum, both anterior and posterior, were delineated, and the septum-to-RV free wall distance was measured. The software automatically detected the RV endocardial boundaries in 3D and computed various parameters, including 3D RV volumes, RVEF, RVGLS and RVFWLS (Fig. 1). In cases where the delineation of RV endocardial boundaries was deemed insufficient for optimal speckle tracking, manual adjustments were made.