What is the incidence of atrial septal defect?

Answer 1

Atrial septal defects (ASDs for short) are caused by a defect in the development of the wall between the two upper chambers (the atria) of the heart.

During the development of the fetus, the heart begins as a single hollow tube that must fold, twist, and otherwise contort itself into the four-chambered heart seen at birth. In early fetal life, the first attempt at this produces a heart with two chambers: an upper atrium and a lower ventricle. These two chambers are then partitioned by adding a wall in the middle of each; thus two chambers become four chambers. The wall that separates the two atria is called the atrial septum, while the wall that separates the two ventricles is called the ventricular septum.

In normal development, the atrial septum begins with a few holes in it. These holes are important for the normal circulatory system of the fetus. During development, however, tissue must grow over these holes in order to sustain life outside of the mother's womb. If the two holes are not completely covered over, then there is a defect in the wall separating the atria -- an atrial septal defect.

The precise causes for atrial septal defects are not known, although they have probably often have to do with defective communication between cells that form the septum. Some septal defects tend to run in families and have known associations with genetic irregularities such as Down syndrome.

Answer 2

Epidemiology of atrial septal defects (ASD)

• 1 in 1500 live births
• 5-10% of all congenital Heart diseases (CHDs)
• 30-50% of complex CHDs
• Female : Male = 2:1

Answer 3

There is no known cause, although some believe that enviromental factors such as pollution play a huge role in this disease/defect.

Answer 4

an abnormal opening in the wall separating the left and right upper chambers (atria) of the heart.