Atrial fibrillation (AFib) is an erratic and often fast beating of the upper part of the heart. The main job of this part of the heart is to push blood into the lower section of the heart. The heart then pushes blood out to the body.
AFib can decrease the amount of blood that reaches the lower section of the heart. Less blood in the heart means there will be less blood pumped out to the body. Blood can also become trapped and pool in the upper heart. This increases the risk of blood clots and stroke. AFib may be:
- Occasional (paroxysmal)—atrial fibrillation starts and stops over short periods usually less than 48 hours
- Persistent—constant over more than 7 days
- Longstanding persistent—continues for more than a year
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The beating of the heart is started and controlled by electrical signals. Normally these signals start from an area of the heart called the SA node. The signals move from the SA node through the heart in an organized way. The upper chambers contract first followed by the lower chambers. AFib is when the upper chambers of the heart activate in an irregular way. It makes the contraction less effective. Causes of Afib include:
- Problem with how the heart developed or damage to the heart
- Metabolic disorders—how your body processes food
- Endocrine disorders—abnormal amounts of hormone in your body
- Certain medications
Sometimes the cause is not known.
AFib is more common in:
- People aged 55 years and older
Other factors that may increase your chance of AFib include:
- Family history of atrial fibrillation
- High blood pressure
- Injury or disease of the heart such as:
- Lung diseases, such as emphysema, asthma, blood clots in the lungs
- Chronic endocrine disorders such as overactive thyroid or diabetes
- Long term prescription medications such as opioids for pain relief
- Receiving general anesthesia
Certain habits and food or drink choices can stimulate the heart. They can increase the risk of AFib:
AFib may not cause any symptoms. Symptoms that do occur may range from mild to severe.
Fast beating in the upper part of the heart may cause:
- Irregular or rapid pulse or heart beat
- Racing feeling in the chest
- A pounding feeling in the chest
If the AFib is decreasing the amount of blood that is being pumped out to the body you may have:
- Lightheadedness, which can lead to fainting
- Pain or pressure in the chest
- Shortness of breath
- Fatigue or weakness
- Hard time exercising
The doctor will ask about your symptoms and medical history. A physical exam will be done to look for any signs of heart disease. The doctor may suspect a problem after listening to the heart and taking a pulse. The doctor may do one or more of the following:
For some people, AFib will go away without treatment. For others, goals of treatment may include:
- Stopping AFib (when possible).
- Slowing the fibrillation down; especially if you are having symptoms.
- Decreasing the risk of other problems such as blood clots and stroke. Very important in AFib that keeps coming back or is permanent.
The exact plan will depend on the cause of your AFib. If a cause is found, that may need to be managed first. For example, stopping or changing medicine may stop the AFib.
Heart Rhythm Control
Steps that may help slow or stop AFib include:
- Medication—to slow the heart rate or keep the heart in a regular rhythm
- Cardioversion —uses an electrical current or drugs to get a normal heart rhythm
- Surgical procedures—to redirect or slow the electrical signals of the heart
Clot and Stroke Prevention
AFib allows blood to pool in the upper part of the heart. Blood clots can form in this pool, travel out of the heart, and cause a stroke. Medicine will help to stop these clots from forming. However, it can also increase the risk of severe bleeding. Most anti-clotting medicine will need close watching by your care team.
A procedure called left atrial appendage closure (LAAC) may be considered if medicine is not an option. This procedure seals off a small area of the upper heart where clots tend to form.
Certain habits can trigger an episode of AFib or make it worse. To decrease the chance of making the AFib worse:
- Stop smoking
- Reduce or eliminate caffeine
- Reduce stress
- Eliminate or reduce alcohol intake
It is not always possible to prevent AFib. Talk to your doctor about your overall heart health. A healthy heart may reduce the risk of some AFib.
American Heart Association
Heart Rhythm Society
Canadian Heart Rhythm Society
Heart and Stroke Foundation of Canada
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Electrical cardioversion. Cleveland Clinic website. Available at: https://my.clevelandclinic.org/health/articles/electrical-cardioversion. Accessed November 28, 2017.
Explore atrial fibrillation. National Heart,Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/af. Updated July 1, 2011. Accessed November 28, 2017.
Left atrial appendage and closure. Cleveland Clinic website. Available at: https://my.clevelandclinic.org/health/articles/left-atrial-appendage-closure. Updated June 2016. Accessed July 14, 2016.
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Last reviewed November 2018 by EBSCO Medical Review Board Michael J. Fucci, DO, FACC Last Updated: 2/2/2018