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Start free with EleplanCor triatriatum sinister
ORPHA:99099Morphological anomaly
Also called Cor triatriatum sinistrum · Divided left atrium
What it is
A rare, congenital, non-syndromic, heart malformation characterized by the presence of a thin, fibromuscular membrane subdividing the left atrium into an upper and lower chamber. The upper chamber receives blood from the pulmonary veins and the lower chamber is attached to the left atrial appendage. Therefore, the membrane blocks the orifice of the mitral valve and leads to obstruction of the left ventricular inflow. It may be asymptomatic or present in infancy with tachypnea, dyspnea, hemoptysis, chest pain, syncope, pulmonary edema, pulmonary hypertension, or heart failure, depending on the degree of obstruction. The anomaly may be isolated or associated with other congenital heart anomalies.
Key facts
- Age of onset
- Adult, Childhood, Infancy
- Classified as
- Morphological anomaly
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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