Diagnosis of persistent left superior vena cava: the role of echocardiography

Persistent left superior vena cava (PLSVC) is a rare but the most common thoracic venous anomaly. It results when the left superior cardinal vein caudal to the innominate vein fails to regress and can be associated with other cardiovascular abnormalities. While PLSVC is often asymptomatic, it can cause serious complications during vascular interventional procedures or surgical treatment of cardiac anomalies. Incidental identification of a dilated coronary sinus on echocardiography should raise the suspicion of PLSVC. The diagnosis should be confirmed by agitated saline contrast echocardiography.