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Atrial Fibrillation Fact Sheet

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In the normal heart, the electrical activity proceeds in an organized manner, going from the atrium and into the ventricles. In a heart with atrial fibrillation, the electrical activity occurs in an unorganized manner rather than being sequential. The irregular line in the electrocardiogram on the right reflects the disorganized electrical activity producing the fine (fibrillating) wavy lines.

Electrical activity of a normal heart (left) and a heart with atrial fibrillation (right).

Atrial fibrillation, often called AFib or AF, is the most common type of heart arrhythmia. An arrhythmia is when the heart beats too slowly, too fast, or in an irregular way. When a person has AFib, the normal beating in the upper chambers of the heart (the two atria) is irregular, and blood doesn’t flow as well as it should from the atria to the lower chambers of the heart (the two ventricles). AFib may occur in brief episodes, or it may be a permanent condition.

AFib Facts1

  • An estimated 2.7–6.1 million people in the United States have AFib. With the aging of the U.S. population, this number is expected to increase.
  • Approximately 2% of people younger than age 65 have AFib, while about 9% of people aged 65 years or older have AFib.
  • African Americans are less likely than those of European descent to have AFib.
  • Because AFib cases increase with age and women generally live longer than men, more women than men experience AFib.

AFib Symptoms

Some people who have AFib don’t know they have it and don’t have any symptoms. Others may experience one or more of the following symptoms:

  • Irregular heartbeat
  • Heart palpitations (rapid, fluttering, or pounding)
  • Lightheadedness
  • Extreme fatigue
  • Shortness of breath
  • Chest pain

AFib Risk Factors

The risk for AFib increases with age. High blood pressure, which also increases in risk with advancing age, accounts for 14% to 22% of AFib cases.2

Risk factors for AFib include2:

  • Advancing age
  • High blood pressure
  • Obesity
  • European ancestry
  • Diabetes
  • Heart failure
  • Ischemic heart disease
  • Hyperthyroidism
  • Chronic kidney disease
  • Heavy alcohol use
  • Enlargement of the chambers on the left side of the heart

AFib increases a person’s risk for stroke by four to five times compared with stroke risk for people who do not have AFib. Strokes caused by complications from AFib tend to be more severe than strokes with other underlying causes. AFib causes 15%–20% of ischemic strokes, which occur when blood flow to the brain is blocked by a clot or by fatty deposits called plaque in the blood vessel lining.2

AFib Costs and Consequences

More than 750,000 hospitalizations occur each year because of AFib. The condition contributes to an estimated 130,000 deaths each year. The death rate from AFib as the primary or a contributing cause of death has been rising for more than two decades.3,4

AFib costs the United States about $6 billion each year. Medical costs for people who have AFib are about $8,705 higher per year than for people who do not have AFib.1,2

AFib Treatment

Treatment for AFib can include:

  • Medications to control the heart’s rhythm and rate.
  • Blood-thinning medication to prevent blood clots from forming and reduce stroke risk.
  • Surgery.
  • Medication and healthy lifestyle changes to manage AFib risk factors.

CDC’s Public Health Efforts Related to AFib

This is a county-level map of atrial fibrillation hospitalization rates in the U.S. Medicare fee-for-service population, ages 65 years and older, 2007-2012. The counties with the highest rates are located from east Texas, Oklahoma, and Missouri to the east and northeast.

U.S. atrial fibrillation hospitalization rates, Medicare beneficiaries aged 65+ years, 2007–2012


  1. January CT, Wann LS, Alpert JS, Calkins H, Cigarroa JE, Cleveland JC Jr, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation. Journal of the American College of Cardiology. 2014;64(21):2246–80.
  2. Mozaffarian D, Benjamin EJ, Go AS, Arnett DK, Blaha MJ, Cushman M, et al. Heart disease and stroke statistics—2015 update: a report from the American Heart Association. Circulation. 2015;131:e29–e322
  3. Agency for Healthcare Research and Quality. Weighted national estimates. HCUP National Inpatient Sample [online]. 2012. [cited 2015 Feb 9]. Available from:
  4. Centers for Disease Control and Prevention. About multiple cause of death 1999–2011. CDC WONDER Online Database. 2014. [cited 2014 Oct 2]. Available from: