Three-dimensional echocardiography in the evaluation of cor triatriatum sinistrum in an adult patient with atrial septal defect.

Cor triatriatum sinistrum is a rare congenital malformation, accounting for 0.1-0.4% of congenital heart disease, characterized by an abnormal fibromuscular membrane which subdivides the left atrium into two chambers. It is generally diagnosed during the neonatal period or early childhood but a minority of patients present in adulthood incidentally. The most common associated cardiac anomalies are atrial septal defect, persistent left superior vena cava and mitral regurgitation. A 28-year-old-male patient was admitted to our outpatient clinic because of palpitation and shortness of breath. His medical and family history was unremarkable. The 12-lead electrocardiogram showed a sinus rhythm. Two-dimensional transthoracic echocardiography revealed dilated right atrium and ventricle, atrial septal defect (ASD) and a membrane at the left atrium (Fig. 1A and Video 1A). The calculated Qp/ Qs was 2.3. Two-dimensional transesophageal echocardiography confirmed cor triatriatum sinister and ASD (Fig. 1B, C and Video 1B, C). For further evaluation of this pathology, we applied three-dimensional transesophageal echocardiography, which revealed a single opening on the fibromuscular membrane (Fig. 1D, E and Video 1D). We measured the area of orifice using iSlice multi-planar review mode as 1.64 cm2 (Fig. F). He underwent the surgical resection of the intraatrial membrane through the left atrium and closure of the atrial septal defect with a pericardial patch. We herein demonstrated two-dimensional and threedimensional echocardiographic features of cor triatriatum sinistrum in a patient with atrial septal defect. For cor triatriatum, three-dimensional transesophageal echocardiography may be useful in revealing the number, shape, area and location of the orifice in detail.