Most patients with persistent left sided superior vena cava remains asymptomatic, it is usually discovered incidentally upon chest imaging. During embryogenesis, the presence of the left anterior cardinal vein and obliteration of the left common cardinal vein leads to the formation of the left superior vena cava. The persistent left sided superior vena cava usually drains into the right atrium (in 80–90%) through a dilated coronary sinus, but in approximately 10 to 20% of cases, it is associated with left atrial drainage.

This case was submitted with supervision and input from:
Soni C. Chawla, M.D.
Health Sciences Clinical Professor,
Department of Radiological Sciences,
David Geffen School of Medicine at UCLA.
Attending Radiologist,
Olive View - UCLA Medical Center.