[Surgical treatment of unroofed coronary sinus coexisting with paroxysmal atrial fibrillation; diagnosis by multidetector computed tomography; report of a case].

We experienced a rare case of an unroofed coronary sinus without a persistent left superior vena cava. A 55-year-old man, who was diagnosed with cerebral infarction, presented with suspected atrial septal defect (ASD) coexisting with paroxysmal atrial fibrillation. Before the operation, we diagnosed this case as coronary sinus ASD by contrast-enhanced coronary computed tomography (CT). There was a 20 mm segment of abnormal communication between the base of the left atrium and the roof of the coronary sinus. We repaired the defect by simple direct closure from the left atrium side, so that the coronary veins drained into the right atrium. The postoperative course was uneventful. Imaging played a crucial role in the diagnosis. Coronary CT angiography is well suited to help identify asymptomatic congenital heart disease.