In this paper we describe a case of an eight-month-old male infant who was diagnosed with an unroofed coronary sinus (UCS) that unusually presented with desaturation and cyanosis after surgical ventricular septal defect (VSD) closure. The patient was initially diagnosed with congenital heart disease (CHD), perimembranous VSD associated with mild stenosis of pulmonary arteries in early newborn period. Although the patient was regularly monitored by a paediatric cardiologist, and was even hospitalized twice due to deterioration of the initially diagnosed disease and the development of congestive heart failure (CHF) and arrhythmias, the UCS went unnoticed. The disease was unveiled completely after VSD was surgically closed and the patient’s condition deteriorated postoperatively with desaturation and cyanosis in the intensive care unit (ICU). On that same day the patient was reoperated on. UCS was closed with a pericardial patch, a persistent left superior vena cava ligated (PLSVC) and the patient successfully recovered. This case is an example that UCS is not only rare but is such an insidious congenital heart disease, often masked with associated heart defects. It should prompt every paediatric cardiologist to perform a careful examination of coronary sinus inflow tract or performance of contrast echocardiography in every suspicious case.
Key words: unroofed coronary sinus, coronary sinus septal defect, postoperative cyanosis, echocardiography