Patient
Information
Primum atrial
septal defect
A primum atrial septal defect is a hole between
the two upper chambers (atria) of the heart. The size of the hole
can range anywhere from small to large, although they are most often
large. Nearly all children with this type of defect also have a gap
(cleft) in the mitral valve and as a result some degree of leaking
at this valve (mitral regurgitation) is almost the rule.
What causes it?
Children are born with this type of defect, but it may not be
identified until toddler age or even later depending on how much of
a noise (murmur) the defect causes. There is no exposure or
activity during pregnancy that we know of that can cause this to
occur. Children with Down’s syndrome are much more likely to have
this condition. Children of parents with this condition have a
9-14% risk of having congenital heart disease themselves.
What problems can it cause?
Physiologically a primum atrial septal defect behaves much as any
other large atrial septal defect (ASD).
Pink oxygen-rich blood returning from the lungs crosses the hole and
it pumped back to the lungs. The result is some wasted work for the
heart, and some enlargement of the right-sided heart chambers (right
atrium and right ventricle) because of the increased amount of blood
flowing through them. Over many years this can result in very
gradual injury to the heart or the lungs, so it is generally
recommended that a primum ASD should be repaired electively between
3 and 5 years of age.
In some children the cleft in the mitral valve
can result in a significant amount of leaking (mitral
regurgitation). In this situation, surgery may need to be scheduled
earlier, either because the leaking is causing more work than the
heart can handle (congestive heart failure),
or because long-term leaking may damage the valve enough to make
repair more difficult.
Some children with large ASDs have problems
with growth, and in such cases weight is generally more greatly
affected than height. Following surgical repair, children who are
small-for-age often do grow better than they did prior to surgery.
Although it has never been studied whether the timing of surgery
plays an important role in the degree of catch up growth following
repair, in the case of children who are having problems with growth
it may make sense to consider earlier repair.
How is it treated?
Occasionally it is helpful for a child with an atrial septal defect
primum to take medications to
help with shortness of breath, but most children have no symptoms
and require no medications. The
only effective treatment is surgical repair. The surgery entails an
incision along the breastbone (sternum) and closure of the atrial
defect with a patch, often made of the child’s own tissue
(pericardium). In many cases the surgeon will also repair the cleft
in the mitral valve at the same time if there is any significant
leaking. Although this operation is an open-heart surgery, it is
usually fairly straightforward and should involve minimal risk when
performed by a skilled surgeon in a center specializing in pediatric
heart surgery.
What happens after surgery?
Following surgery it is necessary to have ongoing cardiology
follow-up, but given a good repair it is quite likely that one will
have normal exercise tolerance and life expectancy. Girls who have
had heart surgery should be able to have normal pregnancies, but
will need to have a cardiologist following them during pregnancy.
Generally, everyone who has had surgical repair of a primum atrial
septal defect will require
endocarditis prophylaxis for at least 6 months after surgery.
If you have more questions about ASDs, please
don't feel uncomfortable asking your pediatric cardiologist.
For more information about ASDs in the Internet, try some of the web links
below. I cannot vouch for the contents, but with the Internet it's
always a case of "browser beware".
American Heart Association
http://216.185.112.5/presenter.jhtml?identifier=11065
A good site to see a brief description of the
different types of heart disease and the treatments available
Boston Children's Hospital
http://web1.tch.harvard.edu/cfapps/A2ZtopicDisplay.cfm?Topic=Atrial%20Septal%20Defect
Overview of atrial septal defects
Royal Children's Hospital in Melbourne
http://www.rch.unimelb.edu.au/cardiology/health-info.cfm?doc_id=3494
eMedicine
http://www.emedicine.com/ped/topic1685.htm
A very clinical discussion intended for physicians, but with a lot
of useful detail if that is what's needed.
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