In a paper to be published in the March 18 edition of the New England Journal of Medicine, researchers have put an end to the ongoing debate about when to treat congenital atrial septal defects (ASD) that cause the right chamber of the heart to enlarge.
"Scientists have long said reparative surgery was unnecessary until the patient started showing symptoms, usually at a later age," says lead author Dr. Michael Gatzoulis, a senior fellow in U of T's department of medicine and a staff cardiologist at the Toronto Hospital (TTH). "We have shown this is wrong, and that surgery earlier in life will actually prevent future symptoms."
Because patients often live symptom-free until middle-age, these defects are often only found by chance, during an electrocardiogram or other examination. "In a previous era, we were only able to pick up these defects at a more advanced stage of the disease," says senior author Dr. Louise Harris, assistant professor in U of T's department of medicine and a staff cardiologist at TTH. "Now we're able to detect them earlier and restore normal blood circulation by closing the hole early enough to hopefully prevent arrhythmia."
One in one hundred Canadians is born with some form of congenital heart disease, with atrial septal defects being the most common form. ASD patients are born with a hole in the wall between the top collecting chambers of the heart which causes the blood to shunt, or flow, from the left to the right chamber. The right side of the heart eventually enlarges as it must work harder to keep the extra blood flowing, leaving the patient with an irregular heart beat or palpitations. Other symptoms include fatigue, lung damage, heart failure and stroke.
"It's clear that people in their 30s or 40s who feel like they've slowed down considerably and who have palpitations, should see a cardiologist. The longer you go without the surgery, the larger your heart becomes and the more likely it is that even after you fix it, you're going to have ongoing or further rhythm problems," Gatzoulis adds.
Researchers examined 213 adult patients (82 men, 131 women) who had undergone surgical closure of hole defects -- the most common congenital heart surgery in adults -- at TTH between 1986 and 1997. The group ranged in age from 16 to 80, with the mean age at 41. Older patients reported a higher incidence of persistent or new arrhythmia following surgery than those under 40. While these older patients also benefit from closure, Gatzoulis says they will require closer monitoring and many will require lifelong blood thinning medication.
"Another observation to come out of this research is that our surgeons are doing a tremendous job. We found zero mortality in roughly 300 consecutive operations involving all of the surgeons at the hospital. That's a pretty impressive record." The University of Toronto Congenital Cardiac Centre for Adults at the Toronto Hospital is the oldest and largest such clinic in the world and is a member of the 15-centre group called the Canadian Adult Congenital Heart (CACH) Network.
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