Heart Rhythm Center

What Is Atrial Fibrillation?

Atrial Fibrillation (AF) is an irregular and often rapid heart rate that commonly causes poor blood flow to the body. During Atrial Fibrillation, the heart’s two upper chambers (the atria) beat chaotically and irregularly—out of coordination with the two lower chambers (the ventricles) of the heart. Atrial Fibrillation symptoms include heart palpitations, shortness of breath, and weakness.

Episodes of Atrial Fibrillation can come and go, or you may have it continually. Although Atrial Fibrillation itself usually isn’t life-threatening, it is a serious medical condition that sometimes requires urgent treatment.

Types of Atrial Fibrillation

  • Paroxysmal Atrial Fibrillation refers to Atrial Fibrillation that occurs occasionally and then stops. The Atrial Fibrillation stops by itself and the heart returns to normal rhythm. The Atrial Fibrillation may last for seconds, minutes, hours, or days before the heart returns to its normal rhythm. People with this type of Atrial Fibrillation usually have more symptoms than others. As the heart goes in and out of Atrial Fibrillation, the pulse rate may change from slow to fast and back again in short periods of time.
  • Persistent Atrial Fibrillation is when the Atrial Fibrillation does not stop by itself. Medications or a special type of electrical shock (called a cardioversion) is used to help the heart return to normal rhythm.
  • Permanent Atrial Fibrillation is when the Atrial Fibrillation cannot be fixed. Medications and controlled electrical shock have failed to return the heart to normal rhythm, and the patient will remain in Atrial Fibrillation for the long term.


A heart in Atrial Fibrillation doesn’t beat efficiently. It may not be able to pump enough blood out to your body with each heartbeat. Many people with Atrial Fibrillation have no symptoms and are unaware of their condition until it’s discovered during a physical examination. Those who do have Atrial Fibrillation symptoms may experience:

  • Palpitations *
  • Decreased blood pressure
  • Weakness
  • Lightheadedness
  • Confusion
  • Shortness of breath
  • Chest pain

* Palpitations are sensations of a racing, uncomfortable, irregular heartbeat or a flopping in your chest.

Possible Causes of Atrial Fibrillation

Abnormalities or damage to the heart’s structure are the most common cause of Atrial Fibrillation.

Possible causes of Atrial Fibrillation include:

  • High blood pressure
  • Heart attacks
  • Abnormal heart valves
  • Heart defects you’re born with (congenital)
  • Overactive thyroid gland or other metabolic imbalance
  • Exposure to stimulants (such as medications, caffeine, or tobacco) or to alcohol
  • Sick sinus syndrome (improper functioning of the heart’s natural pacemaker)
  • Emphysema or other lung diseases
  • Previous heart surgery
  • Viral infections
  • Stress due to pneumonia, surgery or other illnesses
  • Sleep apnea

Risk Factors for Atrial Fibrillation

  • Age. The older you are, the greater your risk of developing Atrial Fibrillation.
  • Heart disease. Anyone with heart disease, including valve problems and a history of heart attack and heart surgery, has an increased risk of Atrial Fibrillation.
  • High blood pressure. Having high blood pressure, especially if it’s not well controlled with lifestyle changes or medications, can increase your risk of Atrial Fibrillation.
  • Other chronic conditions. People with thyroid problems, sleep apnea, and other medical problems have an increased risk of Atrial Fibrillation.
  • Drinking alcohol. For some people, drinking alcohol can trigger an episode of Atrial Fibrillation. Binge drinking (having five drinks in two hours for men or four drinks for women) may put you at higher risk.
  • Family history. An increased risk of Atrial Fibrillation runs in some families.

Complications Caused from Atrial Fibrillation

Sometimes Atrial Fibrillation can cause the following complications:

  • Stroke. In Atrial Fibrillation, the chaotic rhythm may cause blood to pool in your heart’s upper chambers (atria) and form clots. If a blood clot forms, it could dislodge from your heart and travel to your brain. There it might block blood flow—causing a stroke. The risk of stroke in Atrial Fibrillation depends on your age (you have a higher risk as you age) and on whether you have high blood pressure, diabetes, or a history of heart failure or previous stroke, and other factors. Medications called blood thinners can greatly lower your risk of stroke or damage to other organs caused by blood clots. Your doctor will discuss whether you need blood thinning medications, such as Coumadin or Pradaxa, as part of your treatment.
  • Heart failure. Atrial Fibrillation, especially if not controlled, may weaken the heart, leading to heart failure—a condition in which your heart can’t circulate enough blood to meet your body’s needs.

Preparing for Your Appointment

If you think you may have Atrial Fibrillation, it is critical that you make an appointment with your doctor. If Atrial Fibrillation is found early, your treatment may be easier and more effective. Here’s some information to help you get ready for your appointment, and what to expect from your doctor:

  • Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there’s anything you need to do in advance, such as restrict your dietary intake. You may need to do this if your doctor orders blood tests.
  • Write down any symptoms you’re experiencing, including any that may seem unrelated to Atrial Fibrillation.
  • Write down key personal information, including any family history of heart disease, stroke, high blood pressure, or diabetes, and any major stresses or recent life changes.
  • Make a list of all medications, as well as any vitamins or supplements that you’re taking.
  • Take a family member or friend along, if possible. Sometimes it can be difficult to understand and remember all the information provided to you during an appointment.
  • Write down questions to ask your doctor.

Questions to Ask Your Doctor

  • What is likely causing my symptoms or condition?
  • What are other possible causes for my symptoms or condition?
  • What kinds of tests will I need?
  • What’s the best treatment?
  • What foods should I eat or avoid?
  • What’s an appropriate level of physical activity?
  • How often should I be screened for heart disease or other complications of Atrial Fibrillation?
  • What are the alternatives to the primary approach that you’re suggesting?
  • I have other health conditions. How can I best manage them together?
  • Are there any restrictions that I need to follow?
  • Is there a generic alternative to the medicine you’re prescribing?
  • Are there any brochures or other printed material that I can take home with me?
  • What websites do you recommend visiting?

What to expect from your doctors?

Your doctor is likely to ask you a number of questions. Being ready to answer them may save time to go over any points you want to spend more time on. Your doctor may ask:

  • When did you begin experiencing symptoms?
  • Have your symptoms been continuous or occasional?
  • How severe are your symptoms?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?

Tests & Diagnosis

To diagnose Atrial Fibrillation, your doctor may do tests that involve the following:

  • Electrocardiogram (ECG). In this noninvasive test, patches with wires (electrodes) are attached to your skin to measure electrical impulses given off by your heart. Impulses are recorded as waves displayed on a monitor or printed.
  • Holter Monitor. This is a portable machine that records all of your heartbeats. You wear the monitor under your clothing. It records information about the electrical activity of your heart as you go about your normal activities for a day or two. You can press a button if you feel symptoms, so your doctor can know what heart rhythm was present at that moment.
  • Event Recorder. This device is similar to a Holter monitor except that not all of your heartbeats are recorded. There are two recorder types: One uses a phone to transmit signals from the recorder while you’re experiencing symptoms. The other type is worn all the time (except while showering) for as long as a month. Event recorders are especially useful in diagnosing rhythm disturbances that occur at unpredictable times.
  • Echocardiogram. In this noninvasive test, sound waves are used to produce a video image of your heart. Sound waves are directed at your heart from a wand-like device (transducer) that’s held on your chest. The sound waves that bounce off your heart are reflected through your chest wall and processed electronically to provide video images of your heart in motion, to detect underlying structural heart disease.
  • Blood Tests. These help your doctor rule out thyroid problems or other substances in your blood that may lead to Atrial Fibrillation.
  • Chest X-Ray. X-ray images help your doctor see the condition of your lungs and heart. Your doctor can also use an X-ray to diagnose conditions.

Treatment for Atrial Fibrillation

Treatment of Atrial Fibrillation is complex and depends on whether you are currently experiencing symptoms, how long you have been in Atrial Fibrillation, your overall health, and the size and function of the heart’s chambers.

Generally, the goals of treating Atrial Fibrillation are to:

  • Control your heart rate
  • Reset the rhythm back to normal
  • Prevent blood clots

The strategy you and your doctor choose depends on many factors, including whether you have other problems with your heart and if you’re able to take medications that can control your heart rhythm. Your treatment plan will likely first consist of medications to slow your heart rate and blood thinners to prevent clots. Some of these medications can also reset your heart back to its normal rhythm.

When medications do not work to correct or control Atrial Fibrillation, or when medications are not tolerated, a procedure may be necessary to treat the abnormal heart rhythm. These procedures include electrical cardioversion and cardiac catheter ablation. Your doctor will discuss which treatments are best for you.

Lifestyle & Prevention

You may need to make lifestyle changes that improve the overall health of your heart, especially to prevent or treat conditions such as high blood pressure. Your doctor may suggest that you:

  • Eat heart-healthy foods
  • Use less salt, which can help lower blood pressure
  • Increase your physical activity
  • Quit smoking
  • Avoid drinking more than one drink of alcohol for women or more than two drinks a day for men

Educational Resources

The Heart Rhythm Society for information on A-Fib. Click on "AF 360".

A support group for patients and others interested in A-Fib.

Excellent articles, research, and expert medical opinions on A-Fib.

The American Heart Association Web site for heart disease information.

HCMA — the Hypertrophic Cardiomyopathy Association for the heart disorder HCM. 25 to 30 percent of those with the genetic condition HCM experience Atrial Fibrillation sometime during their lives.

A health search engine.

The federally sponsored health site for general medical research.

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