What Is Atrial Fibrillation (AFib) and How Can It Lead to Stroke?

AFib is a common heart rhythm condition that occurs when the upper 
chambers of the heart beat irregularly, or too quickly, and do not pump all of 
the blood to the lower chambers, causing some blood to pool, and potentially form clots. If a clot breaks loose, it can travel to the brain and lead to a stroke.1

Hummingbird Fluttering Icon

There really is no one symptom of AFib. I've heard 
some people describe a fluttering sensation or a 
rapid pulse. I've heard others say it feels like a fish flip-flopping out of water in their chest, or like a hummingbird flopping around inside trying to get out.

–Dr. David McManus, Cardiologist, UMass Memorial Medical Center

Dr. David McManus explains the surprising way his father was diagnosed with
AFib in this article about keeping in mind the signs and symptoms of AFib on The Atlantic.

Signs and Symptoms of AFib

Some people living with AFib have no symptoms; those who do show
signs may experience symptoms, such as:2

  • Orange Irregular Heartbeat Icon an irregular heartbeat
  • Orange Heart With Blue Hummingbird Icon heart palpitations
    (rapid, fluttering or pounding)
  • Man With Chest Pain Icon chest pain
  • Orange Patient With Light Headedness Icon light-headedness
  • Orange Shortness Of Breath Lungs Icon shortness of breath
  • Orange Zzz Icon fatigue

Risk Factors of AFib

Risk factors for AFib can include:2,3

  • advancing age
  • diabetes
  • high blood pressure
  • sleep apnea
  • heavy alcohol use
  • heart disease, such as congestive heart failure
    and coronary artery disease
  • prior heart attacks

The prevalence of AFib is higher in people aged 65 and older.4 Talk to your doctor for more information.

Did You Know?

Orange 5 Times Icon

People with AFib have 
~5 times greater risk
of stroke.4,5

Caution With Heart Icon

Strokes related to AFib are
more likely to be severe than non-AFib strokes.4,6

8 Million Map

In 2020 approximately 8.4 million people in 
the US
are projected to be affected by AFib.7

Some people don’t know 
they have AFib
the condition can have no symptoms.2

Person With Question Mark On Chest Icon
Aging People Walking Icon

As the US population ages, the number of people with AFib
is projected to increase and the condition could affect up to
~12 million Americans by 2030.7

Detecting AFib


  1. National Heart, Lung, and Blood Institute (NHLBI). Atrial fibrillation.  
    https://www.nhlbi.nih.gov/health-topics/atrial-fibrillation. Accessed March 1, 2019.
  2. Centers for Disease Control and Prevention (CDC). Atrial Fibrillation. https://www.cdc.gov/heartdisease/atrial_fibrillation.htm. Accessed August 6, 2020.
  3. Heart Rhythm Society. Risk factors for atrial fibrillation.  
    https://www.hrsonline.org/Patient-Resources/Heart-Diseases-Disorders/Atrial-Fibrillation-AFib/Risk-Factors-for-AFib. Accessed October 10, 2018.
  4. January CT, Wann LS, Alpert JS, et al. American College of Cardiology/American Heart Association Task Force on Practice Guidelines. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation. A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2014;64(21):e1-e76.
  5. Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation is an independent risk factor for stroke: The Framingham Study. Stroke. 1991;22(8):983-988.
  6. Lin H-J, Wolf PA, Kelly-Hayes M, et al. Stroke severity in atrial fibrillation: The Framingham Study. Stroke. 1996;27(10):1760-1764.
  7. Colilla S, Crow A, Petkun W, Singer DE, Simon T, Liu X. Estimates of current and future incidence and prevalence of atrial fibrillation in the U.S. adult population. Am J Cardiol. 2013;112(8):1142–1147.
  8. MedlinePlus. Pulse. https://medlineplus.gov/ency/article/003399.htm. Accessed June 10, 2019.
  9. MedlinePlus. Electrocardiogram. https://medlineplus.gov/ency/article/003868.htm. Accessed June 10, 2019.
  10. MedlinePlus. Auscultation. https://medlineplus.gov/ency/article/002226.htm. Accessed June 10, 2019.
  11. National Heart Lung and Blood Institute (NHLBI). Electrocardiogram. https://www.nhlbi.nih.gov/health-topics/electrocardiogram. Accessed June 10, 2019.
  12. National Heart, Lung, and Blood Institute (NHLBI). Holter and Event Monitors. https://www.nhlbi.nih.gov/health-topics/holter-and-event-monitors. Accessed January 28, 2020.