Cor triatriatum sinistrum--description and review of four cases.

Cor triatriatum sinistrum is a rare congenital cardiac anomaly in which the left atrium is divided into two compartments by a fibromuscular membrane. In most cases, the two cavities communicate through one or more openings. It is generally associated with other cardiac anomalies. The clinical manifestations depend mainly on the size of the fibromuscular membrane orifice(s) and the pressure gradient between the two cavities. The authors present four cases of cor triatriatum sinistrum diagnosed in different clinical contexts and age-groups. In all cases the diagnosis was based on echocardiographic findings (transthoracic and transesophageal) and was supplemented by other imaging modalities.