About one in four adults in the US who are 40 years of age or older will experience an abnormal heart rhythm, also referred to as atrial fibrillation (AF), before they die, according to a report in the rapid access issue of Circulation: Journal of the American Heart Association. The authors note that this is the first time that the lifetime risk of this condition has been determined.
The risk uncovered in the study came as a surprise to lead researcher Dr. Donald M. Lloyd-Jones, from Northwestern University in Chicago. “I was shocked by the finding,” he told Reuters Health. “I was expecting a rate more along the lines of 1 in 10, certainly not 1 in 4.” “I think my expectation was clouded by the fact that the patients we see are often just the symptomatic ones,” he said. This study, however, was able to capture AF patients without symptoms, along with those with symptomatic disease. The findings are based on an analysis of data from 3,999 men and 4,726 women who participated in the Framingham Heart Study and were followed from 1968 to 1999. All of the subjects were at least 40 years of age and free from AF at enrollment. During follow-up, 936 subjects developed AF and 2621 subjects died without developing AF, the authors state. At age 40, the lifetime risks for AF in men and women were 26 percent and 23 percent, respectively. The authors note that a rapid age-related rise in AF rate, coupled with the decrease in remaining years of life, meant that these lifetime risks held fairly stable with increasing age. However, when patients who had heart failure or a heart attack were excluded from the analysis, the risk of AF was reduced to about 16 percent. Lloyd-Jones conceded that some asymptomatic cases of AF will probably never be become serious enough to require medical attention. Still, “we know that patients with one AF event are at risk for having more and that paroxysmal AF confers a risk for stroke that is nearly as high as persistent or chronic AF. So, I don’t think it’s something that we can comfortably ignore.” (SOURCE: Circulation 2004;110: Reuters Health News: Anthony J. Brown, MD : August 2004.)