Healthcare: Cardiovascular Medicine

Atrial Septal Defect


What Is an Atrial Septal Defect?


An ASD is a hole in the wall of tissue that separates the right and left atria (septum). The ASD is a congenital defect (present at birth). Normally, blood that has delivered oxygen to the body returns to the right side of the heart where it is pumped into the lungs to get re-oxygenated. That blood is then delivered to the left ventricle, which pumps the blood to the body. An ASD causes mixing of oxygen rich and oxygen poor blood. This can result in oxygen poor blood being delivered to the body and to abnormal enlargement of the right atrium. This enlargement can lead to the following symptoms:

  • Fatigue
  • Shortness of breath
  • Irregular heart beats
  • Chest pain
  • Symptoms of a stroke

What Are the Types of ASDs?


Ostium Secundum. This is the most common type of ASD and results when a portion of the atrial septum fails to develop normally. This defect can most often be closed via minimally invasive transcatheter procedure.

Ostium Primum. This defect is part of the atrioventricular canal and is associated with a split (cleft) in a part of the mitral valve.

Sinus Venosus. This defect occurs where the superior vena cava (main vein that is returning blood from the upper body) and the right atrium. This defect may be associated with an abnormal pulmonary vein as well.

Coronary Sinus. This defect is located within the coronary sinus, which is the major vein for the heart and is the rarest of all ASDs.


How Is an ASD Diagnosed?


ASD may be diagnosed with a chest x-ray, an ECG (a test that records electrical rhythms), an echocardiogram (a test that uses sound waves to recreate a two- or three-dimensional image of the heart), a CT scan, or cardiac catheterization.


How Is an ASD Treated?


Depending on the patient's symptoms and the size of the defect, the ASD may be treated medically, surgically or with a catheter placed in the femoral vein.