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Epidemiological and mechanistic studies of atrial fibrillation as a basis for treatment strategies.

In this issue of Circulation , Benjamin et al1 provide evidence from the Framingham cohort that atrial fibrillation (AF) increases the mortality rate and that this association persists when adjusted for age, hypertension, smoking, diabetes, electrocardiographic left ventricular hypertrophy, myocardial infarction, congestive heart failure, valvular heart disease, and stroke or transient ischemic attack. The current analysis showed that of the 5209 residents of Framingham who originally enrolled in this population study, 621 developed AF during follow-up. Participants who developed AF were more likely to have hypertension, a smoking habit, electrocardiographic left ventricular hypertrophy, myocardial infarction, congestive heart failure, valvular heart disease, and stroke or transient ischemic attack at baseline. Echocardiographic left atrial dimension was not available for analysis. The age-adjusted odds ratios for death with AF were 2.4 for men and 3.5 for women. After adjusting for risk factor status at each biennial examination, the odds ratios for death were 1.5 for men and 1.9 for women. Much of the excess death attributable to AF occurred soon after diagnosis of AF, but after the first 30-day mortality experience was excluded, there was still a significant association of AF with death during follow-up. There was no interaction between age and AF for death during follow-up; ie, AF increased the likelihood of dying at all ages.

There was a significant interaction between AF and sex with respect to mortality; the presence of AF substantially decreased the survival advantage women usually have over men. The morbidity of patients with AF is well known. The present study documents an independent mortality burden for AF as well. This finding extends previous studies2 3 and motivates the renaissance of research in AF that is currently underway.

The high incidence of AF (more than 2 million Americans), particularly in elderly men,2 and the morbidity …