Pictorial CME

Sinus Venosus ASD – SVC or the IVC type !

Biswajit Paul*

*Consultant Cardiologist, Escorts Heart Institute & Research Centre, Okhla, New Delhi 110025
Received: 16.1.2009; Accepted: 8.3.2009

A patient presented with an echo report of “Sinus venosus atrial septal defect (ASD) – Superior vena caval (SVC) type”. The report had images similar to the one shown in Figure 1. The issue needs certain clarifications.

The most common type of sinus venosus ASD is of the SVC type. However a rare variety, the inferior vena caval (IVC) type is also recognised. It may be seen in Figure 1, that the coronary sinus lies in the plane of the ASD. It is the IVC and not SVC, that lies in the same plane as coronary sinus. It is therefore unlikely that this was a case of SVC type sinus venosus ASD. The fossa ovalis region of the interatrial septum is intact (Figure 2). The defect is located inferior to the foramen ovale and merges with the floor of the IVC. Hence, the diagnosis is “sinus venosus ASD – IVC type”.

Sinus venosus atrial septal defect- inferior vena caval type is an uncommon entity. Differentiating this condition from the more common superior vena caval type requires clear understanding of the anatomy of the interatrial septum.