Increased pulse pressure appears to be an important predictor of risk for new onset atrial fibrillation, according to an article in the February 21 issue of the Journal of the American Medical Association.

Atrial fibrillation is the most common chronic arrhythmia in adults and is associated with increased risk for death and stroke. An estimated 2.3 million adults in the United States have it, and the number is expected to increase substantially as the population ages, making identification of modifiable risk factors important. The prevalence of the arrhythmia increases with age, with a substantial overall lifetime risk of approximately 1 in 4 for both men and women, according to background information in the article. The increase in incidence with age coincides with a rapid age-related increase in aortic stiffness, which is associated with increased pulse pressure, which increases cardiac load and may increase risk for atrial fibrillation.

Gary F. Mitchell, MD, of Cardiovascular Engineering Inc., Waltham, Mass., and colleagues examined the association between pulse pressure and development of atrial fibrillation in 5,331 participants of the Framingham Heart Study who were 35 years r older at baseline and initially without the arrhythmia (median age, 57 years; 55 percent women).

During an average of 16 years of follow-up, 363 men and 335 women developed atrial fibrillation with a median time-to-event of 12 years after pulse pressure assessment. The researchers found that after adjusting for age and sex, a 20 mm Hg increase in pulse pressure was associated with a 34 percent increase in risk for the arrhythmia. The association between pulse pressure and atrial fibrillation remained significant after further adjusting for average arterial pressure and known clinical risk factors; each 20 mm Hg increase in pulse pressure was associated with a 24 percent increase in risk for developing the arrhythmia. In contrast, average arterial pressure was not associated with increased risk for developing atrial fibrillation.

Cumulative 20-year atrial fibrillation incidence rates were 5.6 percent for pulse pressure of 40 mm Hg or less (25th percentile) and 23.3 percent for pulse pressure greater than 61 mm Hg (75th percentile).

"In summary, we have shown that increased pulse pressure, a simple and readily accessible if somewhat indirect measure of arterial stiffness, is likely an important risk factor for development of atrial fibrillation in a community-based sample. Arterial stiffness increases with advancing age, even in a relatively healthy sample. However, increased arterial stiffness with advancing age is not inevitable and appears to be modifiable [such as by reducing various cardiovascular disease risk factors]. As a result, increased arterial stiffness may represent a major modifiable risk factor for development of atrial fibrillation."

"Given the aging of the population, further research is needed to determine whether interventions aimed at reducing pulse pressure or preventing the increase in pulse pressure with advancing age effectively reduce the incidence of atrial fibrillation. In light of the variable and often substantial increase in pulse pressure that accompanies advancing age, lifestyle modifications or therapy aimed specifically at reducing or limiting the increase in pulse pressure with advancing age may markedly reduce the substantial and rapidly growing incidence of atrial fibrillation in our aging society," the authors concluded.