Background: Right ventricular (RV) function assessment is crucial in congenital heart disease (CHD) patients, especially in atrial septal defect (ASD) and repaired Tetralogy of Fallot (TOF) patients with pulmonary regurgitation (PR). In this study, we aimed to analyse both 3D RV shape and deformation to better characterize RV function in ASD and TOF-PR. Methods: We prospectively included 110 patients (≥16 years old) into this case-control study: 27 ASD patients, 28 with TOF and 55 sex-and age-matched healthy controls. Endocardial tracking was performed on 3D transthoracic RV echocardiographic sequences and output RV meshes were post-processed to extract local curvature and deformation. Differences in shape and deformation patterns between subgroups were quantified both globally and locally. Results: Curvature highlights differences in RV shape between controls and patients while ASD and TOF-PR patients are similar. Conversely, strain highlights differences between controls and TOF-PR patients while ASD and controls are similar (global area strain:-31.5±5.8% [controls],-34.1±7.9% [ASD],-24.8±5.7% [TOF-PR], p<0.001, similar significance for longitudinal and circumferential strain). The regional and local analysis highlighted differences in particular in the RV free wall and the apical septum. Conclusion: Chronic RV volume loading results in similar RV shape remodeling in both ASD and TOF patients while strain analysis demonstrated that RV strain is only reduced in the TOF group. This suggests a fundamentally different RV remodeling process between both conditions.