Atrial Septal Defect

An Atrial Septal Defect is also known as an ASD or a “hole in the heart”. It is a type of congenital heart defect, which means it was present at the time of birth. The abnormal opening or “hole” is in the septum (dividing wall) between the two upper chambers of the heart. These upper chambers are called atria. Because of this opening, blood is able to flow from the left atrium to the right atrium. Since pressure in the left side of the heart is higher and since the blood on the left side of the heart is oxygenated, this particular defect allows oxygen-rich blood to be pushed over to the oxygen-poor right side, resulting in too much blood being sent to the lungs. This increase in blood flow makes a “whooshing” sound called a heart murmur.

Causes

A congenital defect occurs during fetal development. The heart is developed during the 5th week of pregnancy. Most of the time, there is no clear cause as to why this happens. ASDs account for 7-10% of all cardiac defects, and 40-50% of them can spontaneously close by the age of 2 years. It is also possible that other genetic syndromes or more complicated cardiac defects can include an ASD.

Signs/Symptoms

This defect is commonly detected in childhood, but may also be found in infancy. These children may have no symptoms at all, and in fact, they may grow and develop normally. However, depending on the size and location of the defect, they may have these signs or symptoms:

  • Poor appetite
  • Poor growth
  • Shortness of breath
  • Tires easily
  • Respiratory infections such as RSV or pneumonia.

If kids with more severe ASDs are not treated, they may develop further complications such as arrhythmias, heart failure, pulmonary hypertension (high blood pressure in the lungs themselves) or stroke. The older a child is, the more complications there may be. If a significant defect is detected at age 2 years or older, the ASD should be surgically closed between ages 2 and 4 years to prevent complications.

Diagnosis

A murmur is often noted on a routine physical exam by the child’s pediatrician. The doctor should refer the patient to a pediatric cardiologist (a doctor who is a specialist in diagnosing and treating childhood heart conditions & diseases) for further evaluation. Because a defect can range in size and location, if the defect is small enough, a murmur may not actually be detected until adolescence or even into adulthood.

Diagnostic Tests

  • Chest X-ray (CXR) – shows the heart, lungs and surrounding organs.
  • Electrocardiogram (EKG) – records the electrical activity of the heart and shows if the right side of the heart is enlarged due to increased blood flow.
  • Echocardiogram (Echo) – similar to an ultrasound; uses sound waves to bounce off the structures of the heart and produces a picture of the heart; shows the volume and direction of flow through the heart itself. This is generally the gold standard for diagnosis of an ASD.

Treatment

There is no specific medical treatment appropriate for this defect. A cardiologist will follow a patient, especially those with small defects, with regular office visits to monitor growth and any other concerns. There is usually no physical activity restriction for these children.

If surgical correction is necessary, many small to moderate defects can be treated in the cardiac catheterization (cath) lab rather than have open heart surgery. This method is preferred since it is much less invasive. In the cath lab, a catheter (a thin, flexible tube) is inserted into a blood vessel in the groin. It is threaded up into the heart, passed through the hole in the heart, and device is deployed. The most common occlusive device is called an Amplatzer Septal Occluder. It resembles a 2-sided umbrella and it covers and seals the defect permanently from both sides. The patient’s own tissue grows over the device and completely covers it in about 6 months. This procedure usually requires only an overnight hospital stay. These patients will need to take a low-dose of aspirin for 6 months because of a small risk of clots forming on the device until the tissue grows over it. The child shouldn’t have a sit-down tub bath or swim for 3 days following the procedure, and they are usually kept out of gym class or sports for approximately one week or until cleared by their doctor. These kids should also have regular follow-ups with their cardiologist.

If open heart surgery is required, a cardio-thoracic surgeon will make an incision in the center of the chest (sternum) to expose the heart. The patient will be on a heart-lung bypass machine for a short period of time while the surgeon is performing the repair. This can be done either by stitching the defect closed or using a patch of special surgical material if the defect is too large to stitch. The tissue of the heart will grow over the stitches or patch within about 6 months. The child will spend several days in the hospital, first in the cardiac ICU, then on a special cardiac unit where the doctors, nurses, and other staff will closely monitor for arrhythmias, breathing concerns, infection or poor eating. Generally, the younger the child is, the less pain they have during the recovery period. This is mainly because the sternum in infants and younger children is more pliable.

The child will have activity restrictions for 6 weeks post-op to prevent injury to the sternum. The parent will be instructed on Systemic Bacterial Endocarditis (SBE) Prophylaxis. This means that the child should have antibiotics before any routine dental work or surgical procedure to prevent an infection on the inside of the heart from occurring. The risk of this is usually diminished after 6 months. All risks and complications will be discussed prior to either a cath procedure or open heart surgery.

Prognosis

After ASD closure, it is common for parents to notice that their child has an increase in exercise endurance and growth. These children have a favorable outlook and go on to live normal, active lives.