Atrial septal defect: Atrial septal defect is a defect in the wall between the two upper chambers of the heart – left atrium and right atrium. This results in blood from the left atrium mixing with that in the right atrium. As a consequence of this left to right shunt, blood flow to the lung increases as the extra blood coming to the right atrium enters the right ventricle and gets pumped to the lungs. In atrial septal defect, right atrium, right ventricle and pulmonary artery get enlarged.
Can atrial septal defect occur in a familial fashion?
Yes some types of atrial septal defects can run in families. This type is usually associated with an abnormality in the ECG known as first degree AV block. In these families, up to 50% of the first degree relative (mother, father, brother, sister, son, daughter) may be affected.
What are the types of atrial septal defects?
Atrial septal defects can be in the high part of the atrial septum (sinus venosus type), middle part (secundum type) or in the lower part (primum type). In adults the most common type is secundum type.
What symptoms can occur due to atrial septal defect?
Atrial septal defect is often silent without any symptoms and detected during routine check up. But it can cause symptoms some times. Due to the defect in the wall between the upper chambers of the heart, blood flows from the left upper chamber to right upper chamber. This extra blood moves to the right lower chamber (right ventricle) and then to the lungs. So the blood flow through the lungs is increased. In the long run this can increase the blood pressure in the blood vessels of the lung (pulmonary hypertension). Still later this can lead to heart failure. Due to the increased flow, right sided chambers of the heart are enlarged. Enlargement of the upper chamber can cause an irregular heart rhythm known as atrial fibrillation. This may be felt as undue prominence of heart beats (palpitation). In long standing cases, pressures on the right side of the heart may go very high so that blood flow across the defect may get reversed (shunt reversal). This leads to deoxygenated blood reaching the left side of the heart and onward to the rest of the body. Higher levels of deoxygenated blood causes bluish discoloration of lips and nails (cyanosis).
Can atrial septal defects be repaired?
Small defects can often be left alone as they do not produce much problems. Larger defects can be repaired by open heart surgery. Selected defects can be closed without surgery using special devices mounted on tubes called catheters, introduced through the blood vessels of the groin. Device closure is being done more frequently due to the availability of better and more durable devices.
What types of atrial septal defects cannot be repaired?
Large long standing defects increase the blood pressure in the lungs to such a high degree that lung vessels get permanently damaged. The blood flow gets reversed across the defect (shunt reversal). This situation is called Eisenmenger syndrome. Such defects cannot be closed. If they are closed, it will lead to failure of the right sided chambers of the heart. Such advanced cases may require a heart lung transplantation.