Cor triatriatum is a rare congenital cardiac anomaly with an estimated incidence among congenital heart diseases of approximately 0.1–0.4%. It is characterized by the presence of a fibromuscular membrane dividing the left atrium or right into two chambers. Approximately 83% of patients with cor triatriatum have cor triatriatum sinistrum (CTS) and 17% have cor triatriatum dextrum (CTD) [1]. CTS usually presents around 31 ± 23 years and is associated with higher rates of cardioembolic events, usually stroke due to mechanisms such as blood flow stagnation within the atrium, its association with atrial fibrillation (AF), and/or the coexistence of an atrial septal defect (ASD) or a patent foramen ovale. In contrast, CTD is associated with a significantly higher rate of cyanosis than CTS and presents earlier in life, usually around 21 ± 20 years [1]. Associated cardiac defects are common, with the most frequent being atrial septal defects (estimated incidence of 53%) and partial or total anomalous pulmonary venous drainage (estimated incidence of 27%) [2]. We describe a case highlighting the role that CTS may play in cardioembolic kidney infarction, provide high-quality cardio magnetic resonance imaging, and two- and three-dimensional echocardiography of the CTS membrane, and outline management strategies for this uncommon clinical scenario.
