Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Atrial fibrillation is an irregular and often fast beating of the upper part of the heart. The main job of the upper part of the heart is to push blood into the lower part of the heart. The lower part of the heart then pushes blood out to the body. Atrial fibrillation can decrease the amount of blood that reaches the lower chambers and then the body. Blood can also pool in the upper heart. This increases the risk of blood clots and stroke. Atrial fibrillation 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
  • Permanent

Atrial Fibrillation

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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 top part of the heart should beat first, then the lower chambers. Any problem in this system can cause atrial fibrillation. Problems may 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.

Risk Factors

Atrial fibrillation is more common in men. It also happens more often in people aged 55 years and older. Other factors that may increase your chance of atrial fibrillation include:

Certain habits and food or drink choices can stimulate the heart. They can increase the risk of atrial fibrillation:

  • Smoking
  • Excessive alcohol use
  • Excessive use of stimulants like caffeine
  • Physical and/or emotional stress


Atrial fibrillation 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 atrial fibrillation is decreasing the amount of blood that is being pumped out to the body you may have:

  • Lightheadedness, which can lead to fainting
  • Sweating
  • 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. To see the electrical activity of the heart, the doctor may do one or more of the following:

  • ECG—pads are put on the skin. Wires connect to a machine that shows the pattern of your heartbeat. This test may be used while at office or hospital.
  • Holter monitor—ECG that is worn over a 24-48 hours period while you do a normal day. It can help show problems that do not occur all the time.
  • Stress testing—ECG during exercise to see changes that only happen with physical activity.


The goal of treatment will depend on the cause of the atrial fibrillation and how much it affects your life. When possible, the fibrillation will be stopped.

  • If it cannot be stopped, the doctor will try to slow it down. This will help to decrease the risk of complications.
  • If a cause is found, treating the cause may stop the fibrillation. This may include stopping or changing medicine that was causing the problem.
  • For some people, atrial fibrillation will go away without treatment.

Some atrial fibrillation keeps coming back or is permanent. This type may need treatment to reduce the risk of other related problems.

Heart Rhythm Control

Steps that may help slow or stop atrial fibrillation include:

  • Medication—to slow the heart rate or keep the heart in a regular rhythm
  • Cardioversion—this procedure that uses an electrical current or drugs to get a normal heart rhythm
  • Surgical procedures—to redirect or slow the electrical signals of the heart
    • Ablation—an area of the heart that is causing the fibrillation may be removed or scarred
    • Maze procedure and mini-maze procedure—a pattern of scar tissue is created to block fast or irregular electrical signals

Clot and Stroke Prevention

If the atrial fibrillation continues, medicine may be needed to decrease the chance of blood clots. Atrial fibrillation 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 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.

Reducing Triggers

Certain habits can trigger an episode of atrial fibrillation or make it worse. To decrease the chance of making the atrial fibrillation worse:

  • Stop smoking
  • Reduce or eliminate caffeine
  • Reduce stress
  • Eliminate or reduce alcohol intake


It is not always possible to prevent atrial fibrillation.