A 25-year-old male presented to clinic with complaints of palpitations. Transthoracic echocardiogram (TTE) showed presence of a membrane in left atrium suggestive of cor triatriatum []. This finding was confirmed with transesophageal echocardiogram (TEE), which revealed a membrane in the left atrium attaching at the Coumadin ridge and the atrial septum, just caudal to the fossa ovalis []. […]

Complementary examinations Electrocardiogram showed sinus rhythm and no signs of cavitary overload. The QRS complex had RS morphology in V1, qRs in V6. AP: +50°, AQRS: +80°, AT: +40°. Chest X-ray showed normal cardiac area (cardiothoracic index: 0.46). The pulmonary vascular net was normal and the medial arch was rectified. […]