Atrial Septal Defect (ASD)

Atrial Septal Defects (ASD): This is a hole (defect) in the wall (septum) dividing the atria. Sometimes these defects remain silent for many years before they are finally noticed. The amount of trouble caused by an ASD is dependent upon its size.

Note that blue blood comes into the right atrium (RA), and circulates through the heart as usual. As the red blood enters the left atrium (LA) from the lungs, the pressure in the LA is higher than that in the RA, and the red blood is forced across the hole where it mixes with the blue blood and is pushed back out into the lungs. This means the lungs see extra blood, and a little bit of what is supposed to be pumped out to the rest of the body is “stolen” by the right heart. Overtime, it is like the patient is running a marathon. The heart eventually gets tired and does not pump as well. The lungs get boggy, and sometimes patients will have frequent colds or asthma as well as early fatigue. Over time, if this sort of hole is a substantial size, and it is not corrected, the patient may experience heart rhythm disturbance.

These sorts of holes may be closed by cardiac catheterization or by surgery.

Superior Vena Cavae (SVC)
Right Atrium (RA)
Left Atrium (LA)
Right Ventricle (RV)
Left Ventricle (LV)