Reduced prevalence of atrial fibrillation in black patients compared with white patients attending an urban hospital: an electrocardiographic study.

Electrocardiographic differences occur between African-American and white persons. The cardiac rhythms of 2123 African-American and white hospital patients from 20 through 99 years of age were studied in a consecutive manner. The prevalence of atrial fibrillation increases dramatically with advancing age in both African-American and white patients. The prevalence of atrial fibrillation begins to increase at age 60 years and continues to increase through the 10th decade of life, although the rate of rise of the prevalence of atrial fibrillation is less in African-American patients compared with white patients. The cause of the reduced prevalence of atrial fibrillation in African-American patients remains unexplained. Atrial fibrillation occurs in 2.5% of African-American patients compared with 7.8% of white patients attending an urban hospital. There is little difference in the prevalence of atrial fibrillation between men and women. Atrial fibrillation occurs nearly seven times more often than does atrial flutter.