For years, doctors have known that atrial fibrillation (AF), or irregular heartbeat, increases the risk for stroke.
But now researchers at Wake Forest Baptist Medical Center have shown that it also increases the risk for heart attack. In fact, for women and African Americans, it more than doubles the risk.
The study is published in the Nov. 4 issue of JAMA Internal Medicine
Approximately three million people in the United States have AF and that number is expected to double in the next couple of decades, according to Elsayed Z. Soliman, M.D., director of the Epidemiological Cardiology Research Center (EPICARE) at Wake Forest Baptist and lead author of the study. Patients with AF have three to five times the risk of stroke and double the risk of mortality compared to those without AF.
"AF is a disease of aging and it is common, costly and has lots of complications," Soliman said. "Our study showed that patients with AF, especially women and African-Americans, are at an increased risk of heart attack compared to those without AF."
The prospective study included 23,928 participants without coronary heart disease from Reasons for Geographic and Racial Differences in Stroke (REGARDS), a large biracial population-based cohort study. The participants were enrolled between 2003 and 2007 and were followed through December 2009.
In the study, the overall increase in risk of heart attack in those with AF, compared to those without AF, was about 70 percent, even after taking into account other cardiovascular disease risk factors, such as hypertension, high cholesterol, body mass index and history of stroke and vascular disease. That risk was more than double in women and African Americans, but less than 50 percent for men and whites, Soliman said.
These findings add to the growing concerns of the seriousness of AF as a public health burden.
"Traditionally, blood thinners are used to manage AF complications such as stroke, but now there is another dimension to the problem. We need to determine the best strategy to prevent heart attack in AF patients while still dealing with potential stroke risk," Soliman said. "In our study, individuals taking blood thinners were at lower risk for heart attack from AF, suggesting a potential role for blood thinners in prevention of heart attacks in AF patients."
Funding for the REGARDS study was provided by a cooperative agreement U01NS041588 from the National Institute of Neurological Disorders and Stroke, National Institutes of Health, Department of Health and Human Services. Additional funding was provided by R01HL080477 from the National Heart, Lung and Blood Institute.
Co-authors include Farah Dawood, M.D., and David Herrington, M.D., Wake Forest Baptist; Monika Safford, M.D., Paul Muntner, Ph.D., Yulia Khodneva, M.D., Ph.D., Evan Thacker, Ph.D., Virginia Howard, Ph.D., George Howard, Dr.PH., and Suzanne Judd, Ph.D., University of Alabama at Birmingham; Neil Zakai, M.D., and Mary Cushman, M.D., University of Vermont.