Cor triatriatum

Cor triatriatum is a rare congenital heart defect where the left or, less commonly, the right atrium is divided into two compartments by an abnormal fibromuscular membrane. This membrane obstructs blood flow from the pulmonary veins to the mitral valve (cor triatriatum sinistrum) or from the vena cavae to the tricuspid valve (cor triatriatum dextrum). The severity of the condition depends on the degree of obstruction and the size of any communication between the two atrial chambers.

This code is used when documentation clearly indicates a diagnosis of cor triatriatum, regardless of whether it's sinistrum or dextrum, and whether it's isolated or part of a more complex congenital heart anomaly. Supporting documentation typically includes echocardiogram reports, cardiac catheterization findings, or surgical reports confirming the presence of the dividing atrial membrane.

• Always specify the type of cor triatriatum (sinistrum or dextrum) if documented, though this code does not differentiate.
• Code any associated congenital heart anomalies separately, as cor triatriatum often coexists with other defects.
• Ensure the documentation clearly identifies the condition as a congenital anomaly, as acquired atrial septations are coded differently.