Atrial Septal Defect: Information on Causes, Diagnosis & Treatments
Atrial Septal Defect (ASD) is a congenital heart defect that is often referred to as a "hole in the heart." As the fetus develops in the mother's womb, a septum (wall) forms to divide the left and right atrium in the heart's upper chamber. An abnormal development of the septum wall can cause a defect that allows blood to flow between the two upper chambers of the heart.
If the ASD is large, the defect can cause significant damage to the child lungs and heart. Many small defects are difficult to detect and usually do not cause any problems. An adult with undetected ASD can die prematurely from high blood pressure or heart failure because the defect can cause preliminary hypertension – a serious condition caused by lung arteries that have become narrow or blocked. Many individuals with atrial septal defect require a surgical repair to prevent or minimize serious life-threatening conditions.
- Who Is at Risk for an Atrial Septic Defect?
- Types of ASD
- Atrial Septic Defect Complications
- Common Symptoms
- Diagnosing the Condition
- Treating Atrial Septic Defect
Who Is at Risk for an Atrial Septic Defect?
Doctors, scientists, and researchers have yet to determine why atrial septal defects develop. However, other congenital heart defects usually develop because of a genetic predisposition (handed down through families) or from genetic problems including Down syndrome. Typically, if a parent was born with a congenital heart defect, there is a potential that the offspring will also develop one.
Many conditions occurring to the mother while pregnant can increased the potential risk of birthing a baby with a heart defect. These conditions could include:
- Rubella Infection – A German measles infection occurring in the first term of pregnancy can increase the potential risk of the fetus developing a heart defect.
- Alcohol, Tobacco, and Drug Use – Consuming alcohol, smoking tobacco products and using some medications and illegal drugs, like cocaine, while pregnant is known to cause significant harm to a developing fetus.
- Obesity – Extremely overweight pregnant women tend to have an increased potential risk of birthing a newborn with a heart defect.
- Lupus or Diabetes – Women who suffer from lupus or diabetes while pregnant are more likely to give birth to a newborn with a heart defect.
- PKU Amino Acid Metabolism Disorder (Phenylketonuria) – Pregnant women with the amino acid metabolism disorder PKU who are not following their prescribed meal plan are more likely to birth a newborn with a heart defect.
Types of ASD
Research has found that most congenital heart defects (those present at birth) occur because of some developmental mistake arising when the fetus' heart is forming in the womb. However, there is usually no identifying cause to the problem. Researchers believe that environmental factors and genetics likely play a role in the development of most heart defects. Doctors categorize atrial septal defects in various forms including:
- Secundum – The most common form of atrial septal defect, this condition develops in the middle of the atrial septum wall.
- Primum – This form of atrial septal defect develops in the lower portion of the atrial septum and often develops with another congenital heart issue.
- Sinus Venosus – Though rare, this form of ASD develops on the upper portion of the atrial septum.
- Coronary Sinus – Though rare, this form of the defect involves a missing portion of the wall between the coronary sinus (the vein system in the heart) and the left atrium.
A small ASD might never cause any significant issue and can often close without treatment during infancy. However, larger atrial septal defects can place the child in a life-threatening condition if it causes a:
- Arrhythmia (heart rhythm abnormality)
- Right-sided heart failure
That said, even a repaired or treated large ASD can cause less serious complications including:
- Pulmonary Hypertension – Untreated atrial septal defect can increase the flow of blood to the lungs, raising blood pressure in the arteries of the lungs and cause pulmonary hypertension. This condition can cause fatigue, dizziness, shortness of breath and severity of symptoms that could lead to right side heart failure.
- Eisenmenger Syndrome – Though rare, atrial septal defects can cause pulmonary hypertension where the lung arteries become blocked or narrowed that eventually lead to permanent lung damage.
Many newborns born with atrial septal defects never display any symptoms or signs of the condition. However, all adults usually notice symptoms of the defect by thirty years of age, and sometimes decades later. The most common ASD symptoms include:
- Swollen abdomen, feet, or legs
- Frequent lung infections
- Shortness of breath, especially during exertion
- Heart palpitations
- Skipped heartbeats
- Heart murmur heard through a stethoscope that is identified as a whooshing sound
Diagnosing the Condition
Usually, the first detect signs of a heart defect including atrial septal defect occur when the pediatrician is performing a regular check up on the child. The doctor hears a murmur through a stethoscope while listening to the heart. If the pediatrician has any suspicions that the child has a heart defect, they may order a test to verify the condition. These tests include:
- Echocardiogram – This test is usually all that is required to accurately diagnose and atrial septal defect. The test involves sound waves that produce video imaging of the structure of the heart and provides valuable information when viewing the heart chambers to measure the strength of its pumping action. The doctor might also look for any indicators of a heart valve defect and use the information to develop an effective treatment plan.
- Chest X-Ray – Many ASDs can be visually seen on a chest x-ray.
- Electrocardiogram (ECG) – This machine records the heart's electrical activity and can quickly identify heart rhythm issues.
- Cardiac Catheterization – The doctor will insert a flexible, long catheter tube into a blood vessel at the armor groin and guide tube into the heart. This diagnostic tool can determine the function of a pumping heart and valves.
- MRI (Magnetic Resonance Imaging) and CT (Computerized Tomography) Scans – While these scans produce visual imagery of the heart, tissue, and surrounding organs, they often do not provide an accurate diagnosis of an atrial septal defect.
Treating Atrial Septic Defect
In many incidences, small and large atrial septal defects will close during childhood without any intervention with medications or surgical procedures. Other times, the atrial septal defect that remains open do not cause any health issues and may not need any treatment. However, persistent problems occurring with atrial septal defects will eventually require some form surgical procedure to repair the problem. These could include:
- Medical Monitoring – Once a child's atrial septal defect has been identified, the pediatrician may recommend monitoring the condition for some time to see if the hole will close without treatment.
- Drugs – Even though medications are unable to repair the defect, they can reduce or manage many of the symptoms associated with an atrial septal defect. These include beta blockers and anticoagulants to manage irregular heartbeats and blood clots respectively.
- Surgical Procedures – Severe atrial septal defects may require cardiac catheterization or open-heart surgery to repair the problem and prevent further harm.
Follow-up care is essential to ensure the atrial septal defect is not causing any problems after closing its own or been surgically repaired. Adults have undergone a repair must routinely follow up with their doctor who can check for any serious complication including arrhythmia, pulmonary hypertension, heart valve problem, or heart failure.