Medical image of the week: duplicate superior vena cava

A persistent left SVC is the most common thoracic venous anomaly and usually opens into the right atrium via the coronary sinus. A central line inserted into the left SVC may be mistaken for placement in other sites such as the subclavian or carotid artery, the mediastinum, the pericardium or pleural space. A duplicate SVC may cause difficulty in introducing central venous catheters or pulmonary artery catheters because of the narrow opening of the coronary sinus to reach the right atrium. In addition, a duplicate SVC is associated with important cardiac conditions such as atrial septal defects and ventricular arrhythmias.