Atrial Septal Defects
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Synonyms of Atrial Septal Defects
- Atrioseptal Defects
- Ostium Primum Defect (endocardial cushion defects included)
- Ostium Secundum Defect
- Sinus Venosus
Atrial septal defects (ASDs) are a group of rare disorders of the heart that are present at birth (congenital) and involve a hole in the wall (septum) that separates the two upper-chambers (atria) of the heart.
Normally the heart has four chambers: two upper chambers known as atria that are separated from each other by a fibrous partition known as the atrial septum and two lower chambers known as ventricles that are separated from each other by the ventricular septum. Valves connect the atria (left and right) to their respective ventricles. A small opening between the two atria (foramen ovale) is present at birth. Shortly after birth, the atrial septum gradually grows and seals this opening. In infants with atrial septal defects, the atrial septum may not close properly or may be malformed during fetal development. In these disorders, the opening (called patent foramen ovale) between the atria persists long after it should be closed, resulting in an increase in the workload on the right side of the heart and excessive blood flow to the lungs.
Initially, the symptoms associated with atrial septal defects may be absent or so mild that they may go unnoticed. Frequently this disorder is not recognized until school age or even adulthood. In adults with undetected atrial septal defects, various respiratory problems and/or heart failure may develop.
Several forms of atrial septal defects are recognized. They are classified according to their location in the septum. The term primum refers to defects that are in the lower part of the septum. The term secundum refers to defects that are located in the middle of the septum, and the term sinus venosus refers to defects in the upper part of the septum.
Atrial Septal Defects Resources
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