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One in Four Adults Over 40 Could Develop Irregular Heartbeat

DALLAS, TX -- August 17, 2004 -- One out of four adults age 40 or older could develop an irregular heartbeat called atrial fibrillation, according to a report in Circulation: Journal of the American Heart Association.

Atrial fibrillation (AF), the most common chronic heart rhythm disturbance, affects about 2.2 million people in the United States, according to the American Heart Association. It's a major risk factor for stroke, increases the risk of death and reduces quality of life.

In AF, the heart's two upper chambers (the atria) quiver instead of beating effectively. Blood isn't pumped completely out of them, so it may pool and clot. If a blood clot leaves the heart and lodges in an artery in the brain, an ischemic stroke results. Atrial fibrillation causes about 15-20% of strokes.

"It has been difficult to gauge the public health burden of atrial fibrillation because it is often 'silent', meaning some patients do not recognize the change in their heart rhythm," said Donald M. Lloyd-Jones, MD, ScM, lead author of the study. "Thus, a large number of individuals may have atrial fibrillation without being aware of it. We have effective medications for reducing the risk of stroke in atrial fibrillation, but if AF goes undiagnosed, we cannot protect people from these potential complications."

Researchers reviewed data from the Framingham Heart Study, in which a large group of participants had documented examinations, medical histories and electrocardiograms (ECGs or EKGs).

The researchers followed 3,999 men and 4,726 women from 1968-99. During the study, 936 participants developed atrial fibrillation and 2,621 died without prior atrial fibrillation.

The researchers found that at age 40, average lifetime risk for atrial fibrillation was 26% for men and 23% for women. "In other words, about one in four would develop AF before they die," said Dr. Lloyd-Jones, an assistant professor of medicine and preventive medicine at the Feinberg School of Medicine at Northwestern University in Chicago.

At age 80, the lifetime risk for AF did not change substantially despite fewer remaining years of life. The risk was 22.7% for men and 21.6% for women at that age.

"To put these findings in context, while the lifetime risks for atrial fibrillation was one in four for adults at age 40, the lifetime risk of breast cancer is one in eight for a woman at age 40," he said.

"For a 70-year-old woman, the lifetime risk for breast cancer is one in 14, while the remaining lifetime risk of AF is still approximately one in four. Atrial fibrillation is predominantly a problem seen in older individuals, who develop it at very high rates, even though they have a shorter remaining lifespan in which to get it."

After excluding patients who developed AF as a result of congestive heart failure or heart attack, lifetime risk of AF was about 16%, which is about 1 in 6 people.

"These lifetime risk estimates are useful in assessing the burden of disease in the population, predicting the future burden of disease, and comparing absolute lifetime risks between common diseases," Dr. Lloyd-Jones said.

The high lifetime risks reported in this study underscore the major public health burden posed by atrial fibrillation and the need for further investigation into predisposing conditions, preventive strategies and more effective therapies, he said.

"We support the American Heart Association's recommendation that people should have their pulse checked by a physician to screen for atrial fibrillation at every doctor's visit, and at least every two years," Dr. Lloyd-Jones said. "People can also learn to check the regularity of their own pulse to help detect atrial fibrillation."

Co-authors are Thomas J. Wang, M.D.; Eric P. Leip, M.S.; Martin G. Larson, Sc.D.; Daniel Levy, M.D.; Ramachandran S. Vasan, M.D.; Ralph B. D'Agostino, Ph.D.; Joseph M. Massaro, Ph.D.; Alexa Beiser, Ph.D.; Philip A. Wolf, M.D.; and Emelia J. Benjamin, M.D., Sc.M.

The National Heart, Lung, and Blood Institute funded this research.

Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.


SOURCE: American Heart Association

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