Sep. 9, 1998 DALLAS, September 8-- Atrial fibrillation -- a condition in which the heart beats irregularly -- significantly increases the risk of dying, particularly for women, report scientists in today's Circulation: Journal of the American Heart Association.
According to the study, men with atrial fibrillation (AF) had a risk of death 1.5 times greater than men without AF. For women, the risk of death was 1.9 times greater in women with AF when compared to women without AF.
Prior research has shown that the condition results in more disability, but in this study researchers looked specifically at death rates and found people with atrial fibrillation had an increased risk of death.
"Women tend to live longer than men," says the study's lead author Emelia J. Benjamin, M.D., associate professor of medicine at Boston University School of Medicine and director of echocardiology for the Framingham Heart Study. "However, in our study, the risk of dying for women with atrial fibrillation at any given age looked similar to men of the same age who had atrial fibrillation."
In the study, the risk for men is heavily influenced by death in the first 30 days after diagnosis, while the increased risk of death for women continues throughout life, says Benjamin. The odds that a woman with AF would die prematurely were actually higher than those for men with the disorder, eliminating the survival advantage that women generally have over men.
AF is caused by a disruption in the rhythm of the atria, the heart's upper two chambers. It causes an irregular heartbeat that results in the heart pumping blood less effectively. About 2 million Americans have AF, according to an editorial in Circulation: Journal of the American Heart Association by J. Thomas Bigger Jr., M.D., professor of medicine and of pharmacology at Columbia University in New York City.
As the Baby Boom generation ages, AF and the sickness and deaths it causes will increase, says Bigger. He also urges greater effort to treat and prevent the disorder.
Because AF often occurs along with other cardiovascular disorders, including heart attacks and stroke, physicians have debated whether it increases a person's risk of death or if it merely reflects the presence of other serious problems.
"We wanted to establish if there was an increased mortality associated with atrial fibrillation," Benjamin explains. "We wanted to answer this question: Are people with atrial fibrillation more likely to die than people without it after adjusting for other risk factors which are known to cause excess death?"
To find the answer, the researchers used data gathered in the Framingham Heart Study. For 50 years, the study, sponsored by the National Heart, Lung, and Blood Institute, has tracked the cardiovascular health of a group of people living in Framingham, Mass.
The scientists examined the medical records of the 5,209 people in the study and found that 621 of them -- 296 men and 325 women -- developed AF between the ages of 55 and 94. Statistical models were used for such risk factors as age, smoking, diabetes, and cardiovascular disorders, including heart attacks, congestive heart failure, and strokes.
People who had AF were more likely to have other cardiovascular risk factors. When the researchers examined this, AF proved an independent risk factor for death.
The researchers also found the risk of dying increased with AF for both sexes in all the age groups studied. For example, men diagnosed with AF between 55 and 64 lived a median of 12.6 years after diagnosis; men of the same age without AF lived 18.1 years. Women in the same age group with the disease had a median survival of 12.1 years compared to 21.3 years for women without it.
"Within the age range we studied, we showed that atrial fibrillation is bad for you," Benjamin says.
The study did not look at the effectiveness of treating AF. However, clinical studies have found some benefit from giving patients the blood-thinning drug warfarin.
In the editorial, Bigger notes a number of therapies for AF are in development or human testing. They include new antiarrhythmic drugs, several new strategies using pacemakers, new surgical and catheter techniques, and implanted atrial defibrillators.
Co-authors of the paper are Philip A. Wolf, M.D.; Ralph B. D'Agostino, Ph.D.; Halit Silbershatz, Ph.D.; William B. Kannel, M.D.; and Daniel Levy, M.D.
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