A 53-year-old man was admitted with progressive exercise intolerance and presyncope. He had no history of congenital heart disease, but had reported these symptoms since childhood. Cardiovascular examination revealed completely normal findings and 12-lead electrocardiography showed sinus rhythm at 70 beats/minute. Two-dimensional echocardiography showed a defined membrane in the left atrium, dividing it into two chambers ( Fig. 1 ), without transmembrane pressure gradient. The right ventricle had normal dimensions and there were no signs of pulmonary hypertension.
The membrane was examined more closely using TEE, which revealed three defects that allowed left atrial filling, demonstrated by colour Doppler ( Fig. 2 ). With three-dimensional TEE we defined the exact membrane morphology; it was multifenestrated, crossing only half of the left atrial cavity ( Fig. 3 ). Both of these noninvasive modalities provided a comprehensive anatomical and haemodynamic evaluation of the anomaly; the final diagnosis was nonstenotic cor triatriatum. The patient was scheduled for regular cardiology follow-up.
