What is an ASD?
Atrial septal defect (ASD) is a hole in the wall (the septum)
between the heart’s two uppermost chambers, the right and left atrium. This hole
allows blood to flow in either direction between the left and right atrium.
ASDs may cause several problems. First, this creates a condition
in which the right side of the heart now contains extra blood, and extra blood
also now flows to the lungs. This diversion of blood puts strain on the heart
because it has to pump this extra blood to the lungs. In addition, the strain
put on the right-sided pumping chamber can lead to a weakening or enlargement of
the right side of the heart and eventually heart failure, if left untreated.
This enlargement may also cause arrhythmias (irregular heart rhythms) to
develop. This extra blood flow to the lungs may damage the arteries to the lungs
over time, leading to high blood pressure in these vessels. Also, ASDs in some
circumstances can allow blood clots from the body to enter the brain and cause a
stroke.
What are the symptoms of an ASD?
Most patients do not have any symptoms in childhood. However,
symptoms that might develop over time, depending on the severity of the ASD and
other factors, include:
- shortness of breath, fatigue, and labored breathing while exercising
- irregular heart beats
- transient ischemic attacks (TIA), which result in stroke-like symptoms
- stroke
- pulmonary hypertension, which is high blood pressure in the arteries of
the lung, and can lead to heart failure if not treated
- reduction in lifespan of about 20 years on average if the ASD is not closed
What causes ASD?
An ASD is congenital, meaning it is a defect that is inborn or
exists at birth. Stated another way, the defect is an abnormality, not a
disease. The septum between the two atrium of the heart did not develop normally
before birth. What is known is that about 20 percent of ASDs that
occur in infants close on their own in the first few years of life.
Heart defects in general. In about 95% of the cases, no
cause can be identified. Sometimes a viral infection can cause heart defects to
develop. Other known causes include genetic factors, certain other medical
conditions (Down’s syndrome, for example), and some prescription and
nonprescription drugs.
How is an ASD diagnosed?
During a routine examination, your doctor may hear a murmur when
listening to the heart. A heart murmur is an additional sound, a swishing sound
heard in the heart. If a murmur is identified, your doctor will order other
tests that can include:
- electrocardiogram (ECG or EKG) - a test that records the electrical
changes that occur during a heartbeat; reveals abnormal heart rhythms
(arrhythmias) and detects heart muscle stress
- chest X-ray - a test to show the size and shape of the heart and
lungs
- echocardiogram - a test that uses sound waves to create a moving
picture of the heart’s internal structures.
- Doppler ultrasound - a test that uses sound waves to measure blood
flow; often combined with echocardiogram to evaluate both the internal
structure of the heart and blood flow across the heart’s valves
- cardiac magnetic resonance imaging (MRI) - a test that uses
three-dimensional imaging to reveal how blood flows through the heart and
how the heart is working
- cardiac catheterization - a procedure that involves inserting a thin
tube (a catheter) into a vein or artery and passing it into the heart to
sample the level of oxygen, measure pressure changes, and make x-ray movies
of the heart and its internal structures.
- angiography - a dye-enhanced x-ray of the heart’s internal
structures
Additional tests may be ordered as necessary.
How is an ASD treated?
If you or your child is diagnosed with an ASD, your primary care
doctor will recommend that you meet with a congenital heart specialist (a doctor
who has the training and equipment to determine the heart problem) who will
arrange for the necessary special tests, medical care, heart procedures, and
follow-up checkups. The best treatment approach will depend on the patient’s
symptoms as well as the size of the ASD. The ASD may need to be closed
surgically through open-heart surgery or may be repaired through an outpatient
catheter-based procedure.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 12/9/2008…#11622
