An Atrial Septal Defect (ASD) is a hole in the part of the septum that
separates the atria (the upper chambers of the heart). This hole allows
oxygen-rich blood from the left atrium to flow into the right atrium instead of
flowing into the left ventricle as it should.
This means that oxygen-rich blood gets pumped back to the lungs, where it
has just been, instead of going to the body.
An ASD can be small or large. Small ASDs allow only a little blood to flow
from one atrium to the other. Small ASDs don't affect the way the heart works
and don't need any special treatment. Many small ASDs close on their own as the
heart grows during childhood.
Medium to large ASDs allow more blood to leak from one atrium to the other,
and they are less likely to close on their own. Most children who have ASDs
have no symptoms, even if they have large ASDs.
The three major types of ASDs are:
defect is in the middle of the atrial septum. It's the most common form of
ASD. About 8 out of every 10 babies born with ASDs have secundum defects.
At least half of all secundum ASDs close on their own. However, this is
less likely if the defect is large.
defect is in the lower part of the atrial septum. It often occurs along
with problems in the heart valves that connect the upper and lower heart
chambers. Primum defects aren't very common, and they don't close on their
Sinus Venosus- This
defect is in the upper part of the atrial septum, near where a large vein
(the superior vena cava) brings oxygen-poor blood from the upper body to
the right atrium. Sinus venosus defects are rare, and they don't close on
are the complications of Atrial Septal Defect?
Over time, if an ASD isn't repaired, the extra blood flow to the right side
of the heart and lungs may cause heart problems. Usually, most of these
problems don't show up until adulthood, often around age 30 or later.
Complications are rare in infants and children.
Possible complications include:
Right heart failure- An ASD
causes the right side of the heart to work harder because it has to pump
extra blood to the lungs. Over time, the heart may become tired from this
extra work and not pump well.
Arrhythmias (ah-RITH-me-ahs)- Extra
blood flowing into the right atrium through an ASD can cause the atrium to
stretch and enlarge. Over time, this can lead to arrhythmias (irregular
heartbeats). Arrhythmia symptoms may include palpitations or a rapid
the lungs filter out small blood clots that can form on the right side of
the heart. Sometimes a blood clot can pass from the right atrium to the
left atrium through an ASD and be pumped out to the body. This type of
clot can travel to an artery in the brain, block blood flow, and cause a
Pulmonary hypertension (PH)- PH is
increased pressure in the pulmonary arteries. These arteries carry blood
from your heart to your lungs to pick up oxygen. Over time, PH can damage
the arteries and small blood vessels in the lungs. They become thick and
stiff, making it harder for blood to flow through them.
These problems develop over many years and don't occur in children. They
also are rare in adults because most ASDs either close on their own or are
repaired in early childhood.
National Heart, Lung, and Blood
Institute (NHLBI) health-related material is provided for information purposes
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Advice on the treatment or care of an individual patient should be obtained
through consultation with a physician who has examined that patient or is
familiar with that patient's medical history.
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