Cor triatriatum is an extremely rare and serious congenital cardiac anomaly.
It is thought to account for ~0.1% of all congenital cardiac anomalies 3,4.
Clinical presentation depends on:
- degree of stenosis in the fibromuscular membrane
- integrity of the interatrial septum
- presence of associated cardiovascular malformations.
It can be a cause of unexplained pulmonary hypertension in children. Typical presentation includes dyspnea, heart failure and failure to thrive 5.
There are two recognised subtypes:
- classic cor triatriatum (cor triatriatum sinistrum / sinister): commoner
- cor triatriatum dextrum / dexter 4
In the classical type there is abnormal incorporation of pulmonary venous structures into the left atrium with an unnecessary fibromuscular membraneous sub division through the atrial chamber.
With cor triatriatum dexter a similar scenario is seen through the right atrium.
Cor triatriatum exists along a spectrum from an imperforate membrane to a membrane with fenestrations, which may allow some passage of blood flow. A highly fenestrated membrane in cor triatrum dexter is sometimes referred to as a Chiari network.
An isolated cor triatriatum demonstrates chest x-ray changes identical to that of mitral stenosis: the heart is normal sized with changes of chronic interstitial oedema.
May allow direct visualisation of the membrane through the atrium +/- visualisation of accessory chamber.
May allow direct visualisation of membrane +/- accessory chamber in greater detail.
Treatment and prognosis
A con triatriatum is usually fatal within the first two years of life. The membrane can be surgically resected. The prognosis is related to timely surgical intervention, the degree of obstruction between the two left atria, and the presence or absence of associated anomalies 5.
History and etymology
The word cor triatriatum essentially means "heart with three atria" due to the accessory chamber created by the membrane appearing as an extra atrium.
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