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Atrial Septal Defects
Above is a drawing of the most common form of atrial defect seen in adults,
the so-called "Secundum Atrial Septal Defect." You will note that
there is an opening between the the right and left atrial chambers. That
is to say, there is a defect in the atrial septal wall.
There is a lot of interesting discussion concerning human development in the
embryo that explains how and why this occurs, but is beyond the scope of my
website.
More importantly, patients may go well into adulthood without having this
defect picked up. The patient may or may not have a murmur.
Shortness of breath and decreased exercise tolerance may be associated with
this problem. Also, patient's can develop a paradoxical embolism,
meaning that a blood clot from the legs can travel to the heart and cross over
to the left side and go to the brain causing a stroke (as opposed to the usual
pathway of going to the lungs and causing a pulmonary embolism).
Standard, time-tested, surgical correction of an atrial septal defect in an
adult involves a relatively simple procedure of sewing a patch over the hole.
Usually, the patch material used a piece of the patient's own pericardium.
The pericardial chamber is the sack that the heart sits within. The
lining of that chamber is known as pericardium. The pericardium
makes a natural tough patch as shown below:
As with many other areas of cardiac surgery, the interventional
cardiologists are devising ways of closing these atrial septal defects without
surgery. There are devices available today whereby a cardiologist in the
cardiac catheterization laboratory will insert a device through a catheter into
the heart that closes off the defect. I have seen this done successfully,
but I am concerned about putting such devices into the heart. The
"non-invasive" procedure is not without risk. There have been reported
cases of the device moving, developing clot, causing strokes, and so on.
Of course, surgery is by no means without risk; however, the surgical repair
of an atrial septal defect can be done safely through small incisions, even
using "minimally invasive" surgical techniques. Moreover, the
surgical patch as shown above represents an exact closure of the defect with
natural tissue. In most surgeons hands, the risk of surgically repairing
an atrial septal defect approaches zero, which of course make it essentially as
safe as any catheter-based (non-invasive) procedure.
Of course, the first person the patient is probably going to see for an
atrial septal defect is a cardiologist. More likely than not, the
clinical cardiologist will then refer the patient to an interventional
cardiologist (often his or her partner) who will then recommend the
catheter-device approach over surgery. Ideally, the patient should get a
second opinion from a surgeon, but often this does not happen. The
patient who is given the choice of "no surgery" versus "surgery" will, of
course, more often than not chose no surgery. However, if a patient is
afforded the opportunity to speak to a surgeon and hear "the whole story"
surrounding surgery for atrial septal defects, then the patient may be better
able to make a truly informed decision.
By no means am I trying to imply that the cardiologists are doing anything
wrong. It is simply two different approaches to the same problem.
This conflict occurs routinely in coronary artery disease patients --that
is, trying to decide between placing stents versus doing bypass surgery.
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