Atrial Septal Defect

Atrial septal defect (ASD) is a congenital heart defect characterized by an abnormal opening in the atrial septum, the wall that separates the two upper chambers of the heart (atria). This opening allows blood to flow between the atria, leading to abnormal blood flow and potential strain on the heart.

 

Types

Atrial septal defects can be classified into several types based on their location and size:

  • Secundum ASD: This is the most common type of ASD, involving an opening in the center of the atrial septum.
  • Primum ASD: This type occurs lower in the atrial septum and is often associated with other congenital heart defects, such as mitral valve abnormalities.
  • Sinus venosus septal defect: This type is located near the vena cava and can be associated with anomalous pulmonary vein connections.
  • Coronary sinus septal defect: This is a rare condition associated with unroofing of the coronary sinus leading to the mixing of venous blood.

 

Symptoms

Small ASDs may not cause noticeable symptoms and may be incidentally discovered later in life. However, larger defects can cause symptoms such as:

  • Shortness of breath, especially during physical activity
  • Fatigue or easy tiring
  • Recurrent respiratory infections
  • Swelling in the legs or abdomen (due to elevated pressure in the heart)
  • Palpitations or irregular heartbeats
  • Stroke or other embolic events in rare cases

In some individuals, ASDs may not cause symptoms until adulthood, while others may experience symptoms from childhood.

 

Risk Factors

Factors that may increase the risk of atrial septal defects include:

  • Family history of congenital heart defects
  • Genetic syndromes, such as Down syndrome
  • Occurs in association with other complex congenital heart defects

 

Diagnosis

The diagnosis of atrial septal defect involves a combination of medical history review, physical examination, and diagnostic tests, including:

  • Echocardiography: This ultrasound test provides detailed images of the heart, allowing visualization of the atrial septum and detecting the presence and size of ASD.
  • Electrocardiogram (ECG): This test records the electrical activity of the heart and may show signs of right atrial enlargement.
  • Chest X-ray: To assess the size and shape of the heart and lungs.
  • Cardiac catheterization: In some cases, a catheter may be inserted into the heart to measure pressures and obtain more detailed information about the defect.
  • Advanced cardiac imaging for better visualization of the defect.

 

Treatment

The treatment of atrial septal defects depends on the size, location of the defect, the presence of symptoms, and the impact on heart function. Treatment options may include:

  • Observation: For small ASDs without symptoms, the doctor may recommend regular check-ups to monitor the defect’s progression and heart function.
  • Medications: Medications may be prescribed to manage symptoms, such as diuretics to reduce fluid buildup or anticoagulants to prevent blood clots.
  • Surgical closure: Larger ASDs or those causing symptoms may require surgical closure. The procedure involves patching or sewing the hole in the atrial septum.
  • Transcatheter closure: In some cases, especially for certain secundum ASDs, a less invasive procedure called transcatheter closure may be used. A device is inserted through a catheter and placed over the ASD to close it.

 

When to Consult a Physician

If you or your child experience symptoms such as shortness of breath, fatigue, palpitations, or swelling, or if there is a known family history of congenital heart defects, it is essential to consult an ACHD physician for evaluation. Early diagnosis and management of atrial septal defects can prevent complications and improve long-term outcomes.