Atrial fibrillation (AF) is known to be associated with increased mortality in patients with heart disease,1,2 but the clinical significance of AF in middle-aged persons without heart disease has not been established.
Conen et al,3 in this well-executed analysis of data from the Women's Health Study, shed light on the consequences of new-onset AF in relatively healthy women. Patients with no known history of AF, myocardial infarction, congestive heart failure, or stroke were observed for incident AF and all-cause mortality during a median follow-up period of 15.4 years. Of 34 722 patients, 1011 (2.9%) developed AF during the study period. Among AF cases, 656 (65%) were paroxysmal, defined as self-terminating and lasting less than 7 days, and 74 (7.3%) were lone, defined as occurring in those younger than 60 years of age and without hypertension or heart failure at the time of diagnosis. Not unexpectedly, hypertension was strongly associated with incident AF: 44% of women who went on to develop AF had hypertension at baseline, compared with 26% of those who remained free of AF. In adjusted analyses, incident AF was associated with a hazard ratio of 2.14 (95% confidence interval, 1.64-2.77) for all-cause mortality. Consistent with prior studies, subjects who developed paroxysmal AF had significantly higher mortality than those who did not develop AF, but lower mortality than those who developed persistent or permanent AF.4,5 Women who developed lone AF had no increase in all-cause or cardiovascular mortality compared with those who did not develop AF.