Which congenital abnormality is most consistent with the findings in this video?

The video shows an apical four-chamber or subcostal echocardiographic view demonstrating a markedly enlarged right atrium with atrialization of part of the right ventricle, displacement of the tricuspid valve septal leaflet downward into the RV cavity, and severe tricuspid regurgitation. These findings are hallmark features of Ebstein anomaly, a congenital malformation of the tricuspid valve causing apical displacement of the septal and posterior leaflets.

Patent foramen ovale and ventricular septal defects have different echocardiographic features without tricuspid leaflet displacement. Eisenmenger syndrome refers to advanced pulmonary hypertension due to shunts but is not a specific congenital structural abnormality.

These diagnostic criteria and echocardiographic hallmarks are described in adult congenital heart disease literature and echocardiography textbooks【16:Textbook of Clinical Echocardiography, 6e†p.570-575】【12:ASE Adult Congenital Guidelines†p.400-405】.