Ostium primum atrial septal defect
Encyclopedia
The ostium primum atrial septal defect (also known as an endocardial cushion defect) is a defect in the atrial septum at the level of the tricuspid
and mitral
valves. This is sometimes known as an endocardial cushion defect because it often involves the endocardial cushion, which is the portion of the heart where the atrial septum meets the ventricular septum and the mitral valve meets the tricuspid valve.
Endocardial cushion defects are associated with abnormalities of the atrioventricular valves (the mitral valve
and the tricuspid valve
). These include the cleft mitral valve, and the single atrioventricular valve (a single large, deformed valve that flows into both the right ventricle and the left ventricle).
Endocardial cushion defects are the most common congenital heart defect that is associated with Down's syndrome.
is occasionally classified as an atrial septal defect
, but it is more commonly classified as an atrioventricular septal defect
Tricuspid valve
The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, between the right atrium and the right ventricle. The normal tricuspid valve usually has three leaflets and three papillary muscles. They are connected to the papillary muscles by the chordae...
and mitral
Mitral valve
The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...
valves. This is sometimes known as an endocardial cushion defect because it often involves the endocardial cushion, which is the portion of the heart where the atrial septum meets the ventricular septum and the mitral valve meets the tricuspid valve.
Endocardial cushion defects are associated with abnormalities of the atrioventricular valves (the mitral valve
Mitral valve
The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...
and the tricuspid valve
Tricuspid valve
The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, between the right atrium and the right ventricle. The normal tricuspid valve usually has three leaflets and three papillary muscles. They are connected to the papillary muscles by the chordae...
). These include the cleft mitral valve, and the single atrioventricular valve (a single large, deformed valve that flows into both the right ventricle and the left ventricle).
Endocardial cushion defects are the most common congenital heart defect that is associated with Down's syndrome.
Classification
A defect in the ostium primumOstium primum
In the developing heart, the atria initially communicate with each other by an opening between the free edge of the septum primum and the AV cushions, known as the primary interatrial foramen or ostium primum , below the free margin of the septum.-Closing of ostium primum:This opening is closed by...
is occasionally classified as an atrial septal defect
Atrial septal defect
Atrial septal defect is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria...
, but it is more commonly classified as an atrioventricular septal defect
Atrioventricular septal defect
Atrioventricular septal defect or atrioventricular canal defect , previously known as "common atrioventricular canal" or "endocardial cushion defect", is characterized by a deficiency of the atrioventricular septum of the heart...
External links
- Down's Heart Group UK National charity related to heart conditions associated with Down's Syndrome.