Atrial fibrillation

At a glance

  • Atrial fibrillation is a type of abnormal heartbeat (arrhythmia) where the heart rate is irregular and too fast.
  • It can cause symptoms such as a racing heart, heart failure and dizziness.
  • It increases the risk of stroke.
  • Effective treatment options are available that can reduce the symptoms and lower the risk of stroke.


Photo of a man holding his chest

In 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 (bpm). Atrial fibrillation causes the heart rate to increase to between 120 and 160 bpm, and even up to 200 bpm in some people.

Other possible symptoms include feeling weak, becoming exhausted faster, chest tightness, light-headedness and dizziness. More than half of all people with don’t notice that they have it – at least at the start.

People with other heart problems may have additional symptoms. For instance, heart failure 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.

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. 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 is usually caused by one of these cardiovascular diseases:

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.

Risk factors

The biggest risk factor is older age.

If you have close relatives (parents, brothers or sisters) who have , you are more likely to develop it yourself. Men have a higher risk than women do. Atrial fibrillation is also more common in people with lighter skin than it is in people with darker skin.

The risk factors that you can influence include the following:

Prevalence and outlook

Atrial fibrillation is the most common type of abnormal heartbeat (arrhythmia). It is estimated that about 2% of the total population is affected. The risk increases with age, to 8% in people over the age of 65.

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.


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). Besides the risk of a stroke, the main things that will determine the type of treatment are whether there are symptoms and how severe they are, and whether the person also has other medical conditions.


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 options for achieving both of these aims:

Treating the symptoms

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

If that doesn’t make a big enough difference, doctors can try to restore the heart’s normal rhythm (rhythm control). This is usually done 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 the has weakened the heart, for instance.

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.

Besides treating the symptoms and preventing a stroke, it is also important to treat any other medical conditions, such as high blood pressure or coronary artery disease.

Everyday life

Most people aren’t aware of their heart if it beats normally. That’s different in people who have : They 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. In our "Health care in Germany" topic you can read about how to find the right doctor – and our list of questions can help you to prepare for your appointment.

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Risom SS, Zwisler AD, Johansen PP et al. Exercise-based cardiac rehabilitation for adults with atrial fibrillation. Cochrane Database Syst Rev 2017; (2): CD011197.

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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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Updated on January 31, 2023

Next planned update: 2026


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

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