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The ostium secundum atrial septal defect is the most common type of atrial septal defect and comprises 6–10% of all congenital heart diseases. It involves a patent ostium secundum (that is, a patent foramen secundum). The secundum atrial septal defect usually arises from an enlarged foramen ovale, inadequate growth of the septum secundum, or ...
The septum primum is on the left side of the heart in the left atrium while the septum secundum is much thicker and is located on the right side, in the right atrium. During development, blood shunts from the floor of the right atrium through the foramen ovale in the septum secundum then up through the foramen secundum in the septum primum. [2]
Most ASD cases are due to the ostium secundum which can happen when the secundum septum doesn’t grow enough during development This actually accounts for about 10-15% of all congenital heart defects and is the most common congenital heart defect in adults.
Some embryologists postulate that the ostium secundum may be formed through programmed cell death. [4] The ostium secundum provides communication between the atria after the ostium primum closes completely. Subsequently, a second wall of tissue, the septum secundum, grows over the ostium secundum in the right atrium. Blood then passes from the ...
A second septum, the septum secundum, semilunar in shape, grows downward from the upper wall of the atrium immediately to the right of the primary septum and foramen ovale. Shortly after birth it fuses with the primary septum, and by this means the foramen ovale is closed, but sometimes the fusion is incomplete and the upper part of the foramen ...
An Atrial septal defect is a relatively common heart malformation that occurs when the interatrial septum fails to develop properly. Persistence of the ostium secundum is the most common atrial septal defect. [3] Additionally, in a subset of the population, the foramen ovale is not overtly patent but the two septa have not fused.
The ostium primum atrial septal 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.
The gap below it is known as the ostium primum (from Latin ' first opening '), and becomes increasingly small. The septum primum eventually fuses with the endocardial cushion, closing the ostium primum off completely. Meanwhile, perforations appear in the superior part of the septum primum, forming the ostium secundum (from Latin ' second ...