Left superior vena cava
- Incidental finding in less than 0.5% of the general population but occurs in approximately 4% of patients with congenital heart disease.
- In most cases, the left SVC is a component of a duplicated SVC. The left brachiocephalic vein is absent, and the right SVC is smaller than the left in 65% of SVC duplications.
- Isolated left SVC is less common.
- The left SVC descends lateral to the aortic arch and drains into the coronary sinus.
- Most often an incidental finding that is not clinically significant, but patients with a left SVC draining into a coronary sinus that has a narrowed ostium have presented difficulties in introducing IV lines and pacemaker or defibrillator leads.
 Imaging Findings
 Plain films
- Most often revealed by radiography when traversed by an IV catheter
- Occasionally detectable, usually in retrospect, as a focal widening of the mediastinum superior to the left side of the aortic knob.
Patient #2: PICC from left superior vena cava to coronary sinus to right atrium to inferior vena cava to left hepatic vein