Shaping insights: 3D echocardiography-derived right ventricular global shape analysis in secondary tricuspid regurgitation subtypes

Abstract Secondary tricuspid regurgitation (STR) is a heterogeneous clinical condition with distinct atrial (A-STR) and ventricular (V-STR) phenotypes, each associated with unique patterns of right ventricular (RV) remodeling. Although functional differences between A-STR and V-STR are well described, global RV shape changes across STR subtypes remain incompletely understood. Accordingly, our study aimed to apply a recently developed and validated three-dimensional echocardiography (3DE)-based method to quantify global RV shape in a large cohort of patients with STR. Patients with available comprehensive 3DE assessment with effective regurgitant orifice area (EROA) values of ≥0.3 cm² (n=140) were retrospectively identified. Based on current guidelines and recommendations patients were further classified into A-STR (n=55) and V-STR (n=85) phenotypes. Using 3DE datasets, RV volumes and ejection fractions (EF) were quantified. To assess the RV’s global shape, 3DE-derived RV mesh models were reconstructed. Using the dimension-adjusted method, reference hemi-sphere, and hemi-cone shapes were created and were compared with the original RV mesh. The end-diastolic hemi-sphericity volume ratio (HSVR) and the hemi-conicity angle (HCA) were introduced (Figure 1) and assessed in A-STR and V-STR patients. Higher values of HSVR and a more obtuse HCA reflect a more spheric RV shape. A-STR patients presented significantly lower RV end-diastolic volume index (EDVi) (A-STR vs. V-STR, 80.3±16.3 vs. 108.6±31.8 mL/m²; p