Irregular Heartbeat Common After 40

Projected Increases in Heart Problems Such as Irregular Beating as Population Ages

From the WebMD Archives

Aug. 16, 2004 -- One in four Americans over the age of 40 will develop an irregular heartbeat called atrial fibrillation at some point in their lives, according to a new study.

Atrial fibrillation (AF) is the most common kind of irregular heartbeat and currently affects nearly 2.3 million people in the U.S. It significantly increases the risk of death and causes an estimated 15% of all strokes.

The study, which appears in the Aug. 31 issue of Circulation: Journal of the American Heart Association, was led by Donald Lloyd-Jones, MD, ScM, of the preventive medicine department at Northwestern University's Feinberg School of Medicine in Chicago.

Lloyd-Jones and his colleagues reviewed data from the Framingham Heart Study, which tracked heart health and risk factors among thousands of men and women from 1968-1999.

For this study, researchers examined information on nearly 4,000 men and 4,726 women, all of whom did not have atrial fibrillation before age 40.

Numbers Hold Steady

The researchers estimated the participant's lifetime risk of AF from age 45 years old to age 95. At age 40 the lifetime risk of AF was 26% for men and 24% for women. The risks of developing the irregular heart rhythm did not change with increasing age and was similar 40 years later. At age 80, average lifetime risk for atrial fibrillation was 23% for men and 22% for women.

"For men and women 40 years of age and older, the remaining lifetime risk for development of [atrial fibrillation] is approximately one in four," write the researchers.

Many people develop atrial fibrillation as a result of heart failure or heart attacks. After eliminating data on this group of people, the lifetime risk of atrial fibrillation in people who had not experienced heart failure or heart attacks was about 16%, or approximately one in six people.

In atrial fibrillation, the heart's two upper chambers (called the atria) quiver instead of beating effectively. Blood isn't pumped completely out of the atria, where it can sit and clot.

If a blood clot leaves the heart and lodges in an artery in the brain, an ischemic stroke results.

Age Counts

The condition mainly hits older people. "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," says Lloyd-Jones in a news release.

Key risk factors for atrial fibrillation include increasing age, high blood pressure, heart attack, heart failure, and problems with heart values, write the researchers.

Atrial fibrillation is "almost certain" to become more common in the coming decades as the American population ages, write the researchers.

The best advice: Get your pulse checked for irregularities seen in atrial fibrillation during every doctor's visit and learn to do it yourself, says Lloyd-Jones.

Show Sources

SOURCES: Lloyd-Jones, D. Circulation: Journal of the American Heart Association, Aug. 31, 2004. News release, American Heart Association.
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