The heart is split into four parts. Two collecting chambers at the top called Atria and two pumping chambers at the bottom called Ventricles. An Atrial septal defect (ASD) is a therefore a hole between the two top chambers - the Atria. There should not normally be a hole in this position as it allows blood to mix between the atria which should normally be separated. This is a reasonably common heart defect and often not to serious so don't be suprised if cardiologist does not hurry to to close the hole (with surgery or with a catheter in some cases).
Click here to see the British Heart Foundation leaflet on Atrial Septal Defect (ASD)or click here to go to the British Heart Foundation website.
Click here to see the Children's Heart Federation leaflet on Atrial Septal Defect (ASD)or click here to go to the Children's Heart Federation website.