ABSTRACT
A coronary sinus ASD is a rare defect believed to occur when the atriosinus venosus fold fails to form. Therefore, instead of the normal draining of the coronary sinus into the right atrium via its usual orifice, there is a persistence of the wide communication between the sinus venosus and both atria. 4 Persistent left superior vena cava terminating in the left atrium is almost always present. Unlike a large coronary sinus receiving a persistent left superior vena cava that eventually drains into the right atrium, this
Figure 19.1 This drawing shows the different types of interatrial septal communications as seen from the right aspect of the atrial septum. CS, coronary sinus; ISV, inferior sinus venosus; IVC, inferior vena cava; OP, ostium primum; OS, ostium secundum; RAA, right atrial appendage; SSV, superior sinus venosus; SVC,
defect allows a communication between the two atria, and the left superior vena cava drains directly into the left atrium.
