arrhythmia key facts Atrial fibrillation (AF) is one of the major risk factors for stroke.1 In 1999, a total of 66,875 deaths with AF as a contributing cause occurred, resulting in an age-adjusted death rate of 24.7 per 100,000 population. 2 Of these deaths, 56,138 (84.0%) were among persons age 75 and older. 3 The greatest proportion of these AF-related deaths occurred among persons age 85 or older (47.4%), followed by those aged 75--84 years (36.6%), aged 65--74 years (12.3%), and aged <65 years (3.7%). 4 Age-adjusted death rates for AF were highest among whites (25.7) and blacks (16.4) and higher for men (34.7) than women (22.8). 5 In 1999, for all deceased who had AF, the most common underlying causes of death were coronary heart disease (28.0%), AF (12.4%), and stroke (10.8%). 6 In 1999, a total of 1,765,304 hospitalizations (137.1 per 1,000 Medicare enrollees) were reported among persons with AF in the Medicare population. Rates increased among successive age groups. 7 The rate of hospitalization among persons with AF was higher among whites (142.7) than among blacks (100.4). Although 55.7% of these hospitalizations were among women, men (162.9) had a higher rate of AF-related hospitalization than women (121.2). 8 The most common diseases listed as the primary diagnosis for persons hospitalized with AF were congestive heart failure (11.8%), followed by AF (10.9%), coronary heart disease (9.9%), and stroke (4.9%). 9 According to the National Heart, Lung, and Blood Institute, there is a gene variant when combined with other factors that increases the risk of life-threatening arrhythmias in blacks. 1MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 2MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 3MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 4MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 5MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 6MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 7MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 8MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999. 9MMWR, February 21, 2003/52(07); 128-131: Public Health and Aging: Atrial Fibrillation as a Contributing Cause of Death and Medicare Hospitalization --- United States, 1999.