Blood pressure offers a new window on heart problems.

Researchers at Cardiovascular Engineering Inc. in Waltham, Mass., looked at the association between pulse pressure - the difference between systolic and diastolic blood pressure - and the development of atrial fibrillation, or AF. The study included 5,331 people ages 35 or older and initially free from AF.

After 16 years, 363 men and 335 women developed AF. The study 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 developing AF.

Cumulative 20-year AF incidence rates were 5.6 percent for pulse pressure of 40 mm Hg or less and 23.3 percent for pulse pressure more than 61 mm Hg.

AF is the most common chronic heart arrhythmia in adults and is associated with increased risk for death and stroke. An estimated 2.3 million adults in the United States have AF, and the incidence increases with age.

The study appears in the February issue of the Journal of the American Medical Association.