[Cor triatriatum in adults: intracardiac echocardiography].

Cor triatriatum occurs during embryological development when the common pulmonary vein fails to incorporate in the left atrium (LA) and gives rise to a fibromuscular membrane that divides the LA into 2 chambers: a superior accessory chamber where the pulmonary veins enter, and an inferior one, the “true” LA, with its auricular appendage, which connects with the left ventricle through the mitral valve. Cor triatriatum is a rare congenital cardiac anomaly (0.4%). A 46-year-old man consulted for palpitations and dyspnea, and atrial fibrillation was noted on the electrocardiogram. Cardiac catheterization was performed and the diagnosis of cor triatriatum was made on echocardiography findings. In the levophase of pulmonary angiography (Figures 1 and 2, anteroposterior and lateral views, respectively), an accessory atrial chamber (AC) connected to the 4 pulmonary veins (*) is observed, as well as considerable IMAGES IN CARDIOLOGY