Persistent left superior vena cava with retrograde flow and absent coronary sinus in a child with ventricular septal defect and patent ductus arteriosus.

Coronary sinus (CS) defects are rare congenital cardiac anomalies that occur in isolation or with other congenital heart diseases. Persistent left superior vena cava (LSVC) is a relatively common entity that usually drains into the CS, is of no hemodynamic consequence, and is easily diagnosed on echocardiography by a dilated CS and an antegrade flow toward the heart. However, a combination of LSVC and CS defect may reverse its flow direction and CS dilation may be absent. In the absence of echocardiographic clues, the reversed flow can be easily misdiagnosed for other structures such as the more common vertical vein of anomalous pulmonary venous connection or the rarer levoatrial cardinal vein. Here, we report a 2-year-old boy with ventricular septal defect, patent ductus arteriosus, absent CS, and a persistent LSVC with retrograde flow producing a hemodynamically significant pretricuspid left-to-right shunt along with its diagnostic challenges. He underwent successful surgical closure of these defects and had been asymptomatic on follow-up.