Missed unroofed coronary sinus

Coronary sinus atrial septal defect ( ASD ) is a rare congenital cardiac anomaly, which might be difficult to diagnose. In this report, we describe a patient with small secundum ASD s and an associated large coronary sinus ASD , which had been missed at initial evaluation. The diagnosis of coronary sinus ASD was established by using transesophageal echocardiography after percutaneous closure of a small secundum ASD at another center. Patient underwent corrective surgery.