Dilated coronary sinus (CS)

Persistent left SVC

Anomalous pulmonary venous drainage into

The CS

Absence of the upper inferior vena cava , a

Large left hemiazygos vein draining into the

CS

Coronary arteriovenous fistula

Unroofing of the CS (septal defect between

LA (left atrium) and coronary sinus)