Background: Cor-triatriatum sinister is a rare congenital heart defect resulting from the division of the left atrium by a fibro-muscular membrane. It is usual for patients to present in infancy and early childhood, although some cases remain undetected until adult life. As a consequence of trans-membrane flow obstruction, the clinical features often mimic mitral stenosis. At present, the reasons for late presentation are poorly understood.
Methods: A complete review of all cases of cor-triatriatum sinister published in the English literature from 1966 to date as mitral stenosis was performed. Statistical analysis was carried out to determine associations between measurements reflecting the communicating membrane fenestration area, the presence of several clinical variables and patient age at initial presentation.
Results: Both pulmonary capillary wedge pressure and mean pressure gradient were significantly higher in younger adults. In addition, the incidence of atrial fibrillation and mitral regurgitation was found to rise with advancing age.
Conclusions: Cor-triatriatum sinister remains an uncommon form of congenital heart disease although it is being diagnosed with increasing frequency in adults due to improvements in diagnostic imaging. This diagnosis should be considered in all patients presenting with signs or symptoms of mitral stenosis.