[Cor triatriatum associated with inter-atrial defect: diagnosis by transesophageal echocardiography].

Cor triatriatum (CT) is a rare malformation consisting of a fibromuscolar membrane that subdivides the left atrium in a postero-superior (or accessory) chamber and an antero-inferior chamber (true left atrium, containing the left atrial appendage). In its classic form, the accessory chamber receives the pulmonary veins and communication with the left atrium is accomplished by way of one or more fenestrations in the membrane. The malformation is usually isolated, but in about one in four patients is associated with other congenital defects of a complex nature. We describe a case of CT associated with atrial septal defect, in which transthoracic echocardiography failed to document the existence of CT membrane, while this abnormality was clearly seen and defined by use of transesophageal echocardiography. The patient was a 26 year-old girl, presented at our outpatient clinic after an episode of palpitations and dyspnea, which lasted for two hours. She suffered of mild dyspnea on exertion during the last three months. Physical examination revealed the typical findings of an atrial septal defect (ASD), and the electrocardiogram revealed right bundle branch block. The two-dimensional echocardiography disclosed an ostium secundum ASD with left to right shunt; dilatation of the right cavities; paradoxical movement of the interventricular septum. A small linear echo originating from the lateral wall of the left atrium, with no evidence of turbulent flow on pulsed wave Doppler and color flow examination, was interpreted as an artifact. Transesophageal echocardiography clearly visualized a tense, bulging membrane separating left atrium into two chambers.(ABSTRACT TRUNCATED AT 250 WORDS)