Tricuspid atresia. View from the right atrium.
The lateral wall of the right atrium is excised. The right atrial appendage (RAA) clearly differentiates from the inferior and superior venue cave.
The large ostium segundum is at the center of the photo.
A dimple in the place of the tricuspid valve is surrounded by blue arrows.
The Tendon of Todaro (red arrows) and the coronary sinus are in normal position.

Image #20