Atrial fibrillation

At a glance

  • Atrial fibrillation is an irregular and often fast heart rate.
  • It can cause symptoms such as palpitations (a pounding or racing heart) and dizziness.
  • Atrial fibrillation isn’t immediately life-threatening, but it increases your risk of a stroke over time.
  • Medication can reduce the symptoms and prevent strokes.
  • Sometimes a procedure to restore the heart rhythm is considered too.


Photo of a man holding his chest

Atrial fibrillation is an abnormal heart rhythm (arrhythmia). It is usually chronic. The heartbeat is continuously irregular and often so fast that the heart pumps less blood into the body. Atrial fibrillation is one of the most common types of irregular heart rate.

Atrial fibrillation isn’t immediately life-threatening. In the long term, though, it increases your risk of a stroke. Thanks to various treatments, most people can live a normal life despite having .


The most common symptom is a pounding or racing heart (palpitations) that can be felt in the chest or neck. The person's pulse is then usually higher and less regular than normal. A healthy resting heart rate usually ranges between 60 and 90 beats per minute. In people who have , this can increase to between 120 and 160 beats per minute.

Other possible symptoms include feeling weak, exhausted, light-headed and dizzy. But up to 30 out of 100 people don’t notice that they have .

People who also have other heart problems may have other symptoms as well. For instance, heart failure (cardiac insufficiency) can lead to shortness of breath and exhaustion, particularly during physical activity.


Every time the heart beats, it contracts (squeezes) and pumps blood into the body. The heartbeat is regulated by electrical signals. The signal that starts a heartbeat is generated in the sinus node, which is found in the wall of the right atrium (the upper right chamber of the heart). This signal spreads like a wave across both atria (upper heart chambers), causing them to squeeze. The sinus node is sometimes described as the heart’s “natural .” A normal heartbeat is known as the sinus rhythm.

Illustration: Normal heartbeat and atrial fibrillation – as described in the article

In , the electrical signals spread across the upper chambers in a chaotic way. This makes them quiver (“fibrillate”) uncontrollably.

The upper chambers of the heart usually help the lower chambers (ventricles) to fill up with blood. They provide about 20% of the heart’s pumping power. In , the heart doesn’t have this extra pumping power. The lower chambers still pump blood into the body, but not as much and in a less regular rhythm.

Atrial fibrillation can be caused by various things. The most common causes include:

Sometimes is caused by a treatable condition such as a leaky heart valve or an overactive thyroid gland. If that is the case, the might go away following heart valve surgery or thyroid treatment.

In about one third of all people who have , the cause remains unknown.

Risk factors

The biggest risk factor is older age. It is estimated that about 2% of the total population and about 7% of people over the age of 65 are affected.

If you have close relatives (parents, brothers or sisters) who have , you are more likely to develop it yourself. Some types of heart surgery can cause too.

The risk factors that you can influence include the following:

  • Alcohol (drinking too much or too regularly)
  • Smoking
  • Diabetes
  • High blood pressure
  • Being very overweight
  • Sleep apnea (pauses in breathing during sleep)


Atrial fibrillation typically occurs in rare, short episodes at first. Over time, it can then gradually progress to longer episodes or permanent . There are four different types, depending on how long the episodes last:

But this classification can only serve as a rough guideline: It often isn’t clear whether someone has already had episodes of in the past, or how long they have already had it for.

The main thing to know is that all types of increase the risk of a stroke. So the specific type of isn’t all that relevant when deciding whether or not to have treatment with anticoagulants (anti-clotting medication).


Although can cause various noticeable symptoms, it is usually not an acutely life-threatening condition. But it can lead to various health problems in the long term. The main ones are:

  • Heart failure (a weak heart, also known as cardiac insufficiency): If the atria (upper heart chambers) no longer squeeze properly, the rest of the heart has to work harder to provide the body with blood. This can become too much for the heart to handle, making it weaker over time. If someone already has heart failure, can make it worse.
  • Stroke: In , the upper heart chambers no longer pump enough blood. As a result, it takes longer for blood to pass through these chambers and it builds up there. This increases the likelihood of blood clots forming. If a blood clot is carried to the brain in the bloodstream, it may block a blood vessel there and cause a stroke.

A person’s individual risk of stroke will depend on whether they have risk factors other than . People who have often have other medical conditions too, such as high blood pressure or coronary artery disease.


Various things can help to get an accurate , find out the cause, and plan the treatment:

  • A talk about your medical history (anamnesis): The doctor asks questions about your symptoms, other medical conditions, age and family history, as well as risk factors for heart disease.
  • Physical examination: This includes measuring your pulse rate and blood pressure.
  • Electrocardiogram (ECG): An ECG measures the electrical activity that regulates the heartbeat. This is a reliable way to diagnose . ECGs can be done when you are at rest, exercising or over a period of 24 hours (Holter monitor).
  • Blood test: Blood tests can be used to check various things, including thyroid function. Atrial fibrillation is sometimes caused by an overactive thyroid gland, or taking too high a dose of thyroid medication. The electrolytes (salts and minerals) in your blood can be measured too. Atrial fibrillation is sometimes associated with an electrolyte imbalance.
  • Ultrasound scan of the heart (echocardiography): This is commonly known as an “echo.” It can be used to, for example, see how big the heart chambers are and check for heart valve problems.

Some tests are particularly helpful when planning treatment: For example, kidney and liver function tests are important because some medications aren’t suitable for people with kidney or liver problems.

Because doesn’t always cause symptoms, it is sometimes discovered by chance, for instance if an ECG is done for a different reason.


There’s a lot you can do yourself to keep your heart healthy – which helps to prevent too:

  • Quit smoking
  • Get more exercise
  • Lose weight (if you’re overweight)
  • Eat less salt (if you have high blood pressure)
  • Drink less alcohol

Research has shown, for instance, that people who have have fewer episodes if they generally avoid alcohol. One study also found that losing weight reduced the symptoms and frequency of episodes.


The treatments for have two main aims: One aim is to get rid of – or at least reduce – the symptoms caused by the irregular heartbeat. The other is to prevent strokes.

There are various medications for each of these aims, with their own advantages and disadvantages.

Treating the symptoms

It is sometimes enough to reduce the too-high heart rate with medication – usually a beta blocker. This treatment takes the strain off the heart and helps to reduce the symptoms. It is referred to as heart rate control.

If that doesn’t make a big enough difference, doctors can try to reset the rhythm of the heart. This approach is known as cardioversion. It attempts to stop the irregular quivering (“fibrillation”) and restore a normal rhythm. Cardioversion is usually done in a hospital by delivering controlled electric shocks to the heart. But the rhythm of the heart may become irregular again afterwards. The risk of this happening can be reduced by treatment with medication or a procedure known as ablation. This is a good idea if your risk is high, or if the has already returned several times.

In rare cases, can become dangerous and, for example, lead to a big drop in blood pressure If that happens, the heart rhythm is usually quickly restored using controlled electric shocks.

Stroke prevention

Most people who have are advised to take medication to prevent strokes. Medications called oral anticoagulants reduce blood clotting and can greatly lower the risk of a stroke.

It is best to talk with your doctor about whether or not to use anticoagulants, and decide together. Here it is a good idea to carefully weigh the pros (stroke prevention) and cons (risk of bleeding). Your personal risk of a stroke and bleeding will depend on your personal risk factors Special calculators can help to determine your risk.

Everyday life

Most people aren’t aware of their heart if it beats normally. That’s different in people who have : They often notice that their heart is not beating as it should. Many find this so worrying that they see a doctor about it. Being diagnosed with might come as a shock at first, but the symptoms can usually be effectively managed using various treatments. Patient education courses can be helpful too: Here people can learn how to cope with the condition in everyday life, and how to use their anticoagulant medication properly. The doctor will help you to apply for patient education.

But many people still feel worried. Some wonder whether they should try to avoid strenuous activities, and whether they can continue living as usual and do things like sports. There’s no medical reason not to. Research has even shown that moderate exercise can improve your physical fitness. It’s best to talk to your doctor about which type of exercise would be suitable.

Further information

There are various sources of support for people who have cardiovascular (heart and blood vessel) disease. These include support groups and information centers. Support services in Germany are often organized quite differently from region to region, though. Our list may help you to find useful places to turn to.

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.

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IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Please note that we do not provide individual advice on matters of health. You can read about where to find help and support in Germany in our information “How can I find self-help groups and information centers?

Updated on January 5, 2021
Next planned update: 2024


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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