The membrane divides the right atrium into a proximal (upper) and a distal (lower) chamber. The upper chamber receives the venous blood from both vena cavae and the lower chamber is in contact with the tricuspid valve and the right atrial appendage. Mechanism
The natural history of this defect depends on the size of the communicating orifice between the upper and lower atrial chambers. If the communicating orifice is small, the patient is critically ill and may succumb at a young age (usually during infancy) to congestive heart failure and pulmonary edema. If the connection is larger, patients may present in childhood or young adulthood with a clinical picture similar to that of mitral stenosis. Cor triatriatum may also be an incidental finding when it is nonobstructive. Diagnosis by ECHO, possibly followed by MRI. Diagnosis
Primarily diagnosed with imaging, such as echocardiogram, CT, and/or MRI. Treatment
The disorder can be treated surgically by removing the membrane dividing the atrium. References
Church WS. Congenital malformation of heart: abnormal septum in left auricle. Trans Path Soz. 1868;19:188-190.Griffith TW. Note on a Second Example of Division of the Cavity of the Left Auricle into Two Compartments by a Fibrous Band. J Anat Physiol. Apr 1903;37:255-7. [Medline].Anderson RH. Understanding the nature of congenital division of the atrial chambers. Br Heart J. Jul 1992;68(1):1-3. [Medline].Richardson JV, Doty DB, Siewers RD, et al. Cor triatriatum (subdivided left atrium). J Thorac Cardiovasc Surg. Feb 1981;81(2):232-8. [Medline].Trento A, Zuberbuhler JR, Anderson RH, et al. Divided right atrium (prominence of the eustachian and thebesian valves). J Thorac Cardiovasc Surg.
Paroxysmal tachycardia is a form of tachycardia which begins and ends in an acute (or paroxysmal) manner. It is also known as "Bouveret-Hoffmann syndrome". Cause
The cause of this condition is not accurately known, though it is probably of nervous origin and can be aggravated by physical wear and tear. The symptoms are sometimes very alarming but it is not considered in itself dangerous.It has an increased risk of developing in WPW syndrome and LGL syndrome. Diagnosis
Classification
It can be divided by the origin:
supraventricular tachycardia
ventricular tachycardia


== References ==