Cor triatriatum sinister is a rare congenital cardiac anomaly that has been identified in 0.1% of children with congenital heart disease. It is defined as a fibromuscular membrane that divides the left atrium into two chambers: a superior (proximal) that in most cases receives drainage from the pulmonary veins and an inferior (distal) chamber that communicates with the mitral valve and the left atrium. Cor triatriatum sinister can be an isolated lesion (approximately 25% of cases), but in many cases it is associated with other congenital cardiovascular anomalies, the most common one being – atrial septal defect(3). Symptoms in patients with cor triatriatum sinister are related to obstruction of pulmonary venous drainage, pressure loading of the right side of the heart and congestive cardiac failure. Depending on the severity of the obstruction and presence of associated cardiac anomalies it can be diagnosed at any age. Diagnosis is usually achieved by echocardiography in early infancy. Elective treatment method is surgical excision of the membrane. Here we present a pediatric patient (4 months old) presenting in cardiogenic shock with a successful correction of isolated cor triatriatum sinister. To confirm diagnosis and success of surgical repair, transthoracic and transesophageal echocardiography were used.
