Abstract
Among congenital cardiac defects, cor triatriatum sinistrum is a rare formation of 3 distinct atrial chambers in the heart. Depending on the size of the defect in the membranous septum, the symptoms can range from asymptomatic to severe pulmonary hypertension. Individuals can go years, sometimes to the second and third decades of life, before presenting with symptoms. Although it is well known to be associated with pulmonary veno-occlusive disease, the association with hemolytic anemia is much less well known. Identifying the subtle signs and symptoms of cor triatriatum in the emergency department can save a life. Here, we present the case of a 6-month-old infant with hemolytic anemia in the setting of right-sided congestive heart failure leading to the diagnosis of cor triatriatum. Anemia developed secondary to shearing stress caused by the heart defect itself. Complete resolution of symptoms occurred status post septectomy and repair of the defect.