Atrioventricular Septal Defects
What
Are Atrioventricular Septal Defects?
Atrioventricular septal defects involve
a large hole in the septum, the wall that
separates the right and left sides of the
heart. Defects may develop at a number of
locations in the wall. AVSD ranges in severity
from a small atrial septal defect to a complete
atrioventricular septum defect in which
there is only one valve over a large hole
between all four chambers. This results
in too much blood flowing to the lungs and
the heart becomes enlarged from working
too hard.
Also called atrioventricular canal defects,
endocardial cushion defects and AV septal
defects, partial AVSDs account for about
5 percent of all congenital heart disease.
AVSDs usually are complex defects. They
may be complete or partial:
- Complete - Complete canal defect involves
a hole where the upper and lower parts
of the septum meet, as well as the defects
in the mitral
valve and tricuspid
valve. Just one valve and one hole
may be present. As a result of these defects,
blood flows in all directions inside the
heart. Most complete AVSDs occur in patients
with Trisomy 21 (Down syndrome).
- Partial - In a partial canal defect,
either the upper or lower septum may be
affected. Usually the defect involves
the lower portion of the atrial septum
and is associated with a mitral
valve defect. Rarely, a partial defect
may involve the ventricular septum, with
or without a mitral valve abnormality.
Most partial AVSDs occur in non-Down syndrome
patients.
AVSDs also may occur in association with
tetralogy of fallot
Symptoms
Symptoms of AVSDs depend on the size of
the ventricular septal defect and the resistance
to blood flow in the pulmonary circulation.
When there is a large ventricular septal
defect, the symptoms of congestive
heart failure occur.
If an AVSD is suspected, the following
diagnostic tests may be performed:
Treatment Options
AVSD are complex defects that require the
expertise of experienced cardiologists.
Surgery to correct a complete AVSD is usually
done in the first few months after birth.
Surgical repair will close the hole with
one or two patches and the single valve
is split to create a tricuspid valve and
a mitral valve. Rarely, the defect may be
too complex to repair in infancy. In this
case a procedure called pulmonary artery
banding will reduce the blood flow and high
pressure in the lungs. Later the band is
removed and surgical repair is done.
Follow-up Care
Some patients with residual defects, such
as a leaky valve (regurgitation), may benefit
from medications to lower blood pressure
and help the heart pump better. Patients
with congenital AVSD are at risk for bacterial
endocarditis,
an infection of the heart’s valves
or inner lining (endocardium.) Before having
certain dental or surgical procedures performed,
it may be necessary to take preventive antibiotics.
Need an appointment? Request one online 24
hours a day, 7 days a week; or call 800-789-PENN (7366) to speak to a
referral counselor.
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