Diseases & Conditions

Atrial Septal Defects


Overview, Causes, & Risk Factors

Atrial septal defect, ASD, is a congenital defect of the heart, or one present at birth. There is an abnormal opening in the wall that separates the two upper chambers of the heart.

What is going on in the body?

The heart has four chambers. The two upper chambers are called the atria. An ASD is a defect or hole in the wall between these chambers. The hole allows blood to flow abnormally between the chambers. ASD is a fairly common cause of congenital heart disease.

What are the causes and risks of the condition?

The exact cause of ASD is often unknown. The heart develops abnormally before the person is born. Some factors that increase the risk of ASD are:

  • alcohol ingested by the mother during her pregnancy
  • chromosomal abnormalities, such as Down syndrome or Turner''s syndrome
  • an infection, such as rubella, within the womb
  • medicines and drugs, such as retinoic acid, taken by the mother during pregnancy

  • Symptoms & Signs

    What are the signs and symptoms of the condition?

    Symptoms of an ASD depend on how large the defect is and where it is located. People with small defects may not have any symptoms. Symptoms can occur during infancy and childhood if there is a large defect. Many times, symptoms do not appear until adolescence or adulthood. Someone with an ASD may have the following symptoms:

  • delays in a child's development, including thinking and motor functions
  • difficulty breathing and shortness of breath, often made worse by activity
  • fatigue
  • failure to thrive, which is a slow growth rate in infants
  • heart murmurs that a healthcare provider can hear with a stethoscope

  • Diagnosis & Tests

    How is the condition diagnosed?

    Diagnosis of ASD begins with a medical history and physical exam. An EKG or heart tracing may show certain abnormalities. A chest X-ray may show enlargement of the heart or certain blood vessels. Often, an echocardiogram, or ultrasound of the heart, is used to diagnose the defect. A special X-ray test called a cardiac catheterization is generally used to confirm the diagnosis.


    Prevention & Expectations

    What can be done to prevent the condition?

    An atrial septal defect is often not preventable. Pregnant women should avoid alcohol. A woman who may get pregnant should make sure all her vaccines are up to date, to lower the risk of infection in the womb.

    What are the long-term effects of the condition?

    The effects of an ASD depend on the size and location of the defect. Breathing problems and congestive heart failure can occur with serious unrepaired defects. An ASD may also cause arrhythmias and infections of the heart or lungs. The ASD may occur together with other congenital heart defects, such as ventricular septal defect. This combination can worsen the effects of the defect.

    What are the risks to others?

    An ASD is not contagious and poses no risk to others.


    Treatment & Monitoring

    What are the treatments for the condition?

    If the ASD is small, the person may not need treatment. Congestive heart failure and arrhythmias may be treated with medicines. People with large defects usually need open heart surgery. This helps prevent further heart and lung problems. Surgery is generally very effective in closing the defect and is quite safe. People with heart and lung problems from their defect may need medical treatment before they can have surgery.

    What are the side effects of the treatments?

    Surgery carries a risk of bleeding, infection, and allergic reaction to anesthesia. Rarely, arrhythmias or death occur because of the surgery. Medicines used for congestive heart failure or arrhythmias may cause allergic reactions or salt imbalances.

    What happens after treatment for the condition?

    In uncomplicated cases, people can usually return to normal activity after recovery. Some people may require further treatment if heart or lung damage was severe before surgery.

    How is the condition monitored?

    In some cases, the individual may have regular visits with the healthcare provider. Periodic EKGs and echocardiograms may be ordered. Any new or worsening symptoms should be reported to the healthcare provider.


    Attribution

    Author:Eric Berlin, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:08/31/01
    Reviewer:Eileen McLaughlin, RN, BSN
    Date Reviewed:08/01/01

    Sources

    Merck Manual 1999

    Current Medical Diagnosis and Treatment, 1996

    Harrisons Principles of Internal Medicine, 1991