Heart rhythm disorders (arrhythmias)

At a glance

  • In heart rhythm disorders (arrhythmias), the heart may beat too slowly, too fast or at an irregular rate.
  • Typical symptoms include a fluttering, pounding or racing feeling in your chest.
  • The abnormal heartbeat is often caused by a heart disease, like coronary artery disease or a leaky heart valve.
  • There are various treatment options, depending on the cause and severity of the symptoms. These include medication and surgical procedures.


Photo of a grandmother with her grandchild

The beating of the heart is triggered by electrical signals that start in the right upper chamber (atrium) of the heart. These signals are normally given off at a regular rate and quickly spread across the entire heart muscle. Depending on what you’re doing, your heart beats slower or faster to make sure that enough blood is always pumped around the body. Even in a healthy heart, the rhythm of the heartbeat isn’t always completely regular. It is normal to briefly have “extra” heartbeats several times a day (known as premature heartbeats, or extrasystoles).

But if the heartbeat is always irregular – or so different to a normal heart rhythm that it causes symptoms – it is considered to be a heart rhythm disorder (arrhythmia). Then the heart may beat

  • too slowly (bradycardia),
  • too fast (tachycardia), or
  • at irregular intervals.

Sometimes, there are several problems at the same time – like in atrial fibrillation, where the heart often beats too fast and at an irregular rhythm.


Some people notice that they have an irregular heartbeat because they have a fluttering or pounding feeling in their chest (palpitations). If your heart beats very fast while you’re at rest, you might feel the high pulse as a racing heart. But if the heart only briefly “skips a beat,” a heart rhythm disorder may go unnoticed.

Other symptoms usually only develop if the heart beats so abnormally that it can no longer pump enough blood around the body: If your brain doesn’t get enough oxygen as a result, you may become dizzy or unconscious.

The heart muscle itself needs oxygen too. If it gets too little oxygen because of an abnormal heartbeat, you may have chest pain. Some people have difficulty breathing and feel weak too.

Causes and risk factors

A heartbeat that is too slow (bradycardia) is usually caused by something known as AV block. Here the electrical signals that travel from the upper heart to the lower heart are passed on later than usual, or aren’t passed on at all for short amounts of time. Bradycardia may also occur if the heart’s natural (the sinus node) fails to send some signals or can no longer send them properly.

People with often have a fast heartbeat (tachycardia) together with an irregular heart rate. Other causes of a fast heartbeat include atrial flutter and scar tissue in the heart.

Heart problems like , AV block and scarring are usually caused by heart diseases too, such as

Because of this, factors that damage the heart (like high blood pressure, smoking, drug abuse and too much alcohol) can also increase the risk of abnormal heartbeats.

Some people are born with a heart rhythm disorder – for instance, due to defects affecting electrical pathways in the heart. Then additional pathways carry electrical signals from the upper heart to the lower heart, which may cause the heart to suddenly beat very fast. This can also happen if you inherit heart cells that don’t work properly.

Further possible causes of an abnormal heartbeat include certain other diseases, like an overactive thyroid, chronic kidney disease or diabetes. Electricity-related accidents and injuries can affect your heart rhythm too.

Sometimes, though, abnormal heartbeats develop in people with a healthy heart and without other medical conditions. Then the abnormal heartbeat is said to be “idiopathic.”

Abnormal heartbeats can occur as a side effect of certain medicines, including some heart medicines and blood-pressure-lowering medicines, as well as some antidepressants and cancer medicines.

Prevalence and outlook

Heart rhythm disorders are common – especially in older people and those who already have another heart condition. In those cases, the abnormal heartbeat usually has to be treated. In younger people who are otherwise healthy, an abnormal heartbeat is often less of a problem. Genetically inherited heart rhythm disorders are different, though. They can sometimes be life-threatening.

Abnormal heartbeats can start suddenly and then go away again after a few seconds or minutes. Sometimes these episodes repeat regularly. In certain disorders, the heart rhythm is never normal.


Abnormal heartbeats sometimes lead to sudden fainting – with a risk of falls and injuries. They can also result in heart failure or make existing heart failure worse.

In , blood clots may form in the heart. If these clots break loose, they can travel through the bloodstream to the brain and cause a stroke.

The risk of life-threatening complications is greater if the heart is already damaged – for instance, because of a heart attack. Then abnormal heartbeats can cause circulatory failure, cardiac arrest or ventricular fibrillation (V-fib). In V-fib, the heart rate is so fast that the individual beats aren't strong enough to pump blood around the body. Without resuscitation, people can die as a result (sudden cardiac death).


An abnormal heartbeat may be felt as a racing, fluttering or pounding sensation in the chest. Sometimes, a doctor notices that the heartbeat is too slow, too fast, or irregular when measuring someone's pulse or listening to their heart with a stethoscope.

An electrocardiogram (ECG) can be used to find out exactly what type of abnormal heartbeat it is. If there's reason to believe you have a heart rhythm disorder, but the ECG readings are normal, that might be because your heartbeat only becomes abnormal every now and then, or only under physical strain. For this reason, a continuous ECG recording or stress test ECG is often done to be sure.

Other examinations may help to find out the causes or effects of the abnormal heartbeat. For example, an ultrasound scan of the heart (echocardiogram) can detect heart failure.


The treatment options for an abnormal heartbeat will depend on the answers to the following questions:

  • What kind of abnormal heartbeat is it?
  • What is causing it, and can the cause be treated?
  • How severe is it?
  • Is it causing symptoms?
  • Is there a higher risk of complications such as stroke or life-threatening ventricular fibrillation?

Because of this, different people may have very different treatments: Some don’t need any treatment. Those with a type of rapid heartbeat called PSVT can sometimes make it go away themselves using a special breathing technique. Others take medicine to stabilize their heart rhythm. Some need treatment with brief, controlled electric shocks to restore a normal rhythm (cardioversion). Certain surgical procedures can help too. One example is catheter ablation, which aims to destroy (ablate) the heart tissue that is causing the abnormal heartbeat.

If the heart needs support on a more permanent basis, special electrical devices may be considered: People whose heartbeat is too slow – for instance, due to AV block or because the sinus node isn't working properly – may need a pacemaker. Abnormal heartbeats that could lead to life-threatening ventricular fibrillation can be treated with a device called a defibrillator.

Sometimes there are a number of treatment options that have different pros and cons. Then you can use our decision aid to help choose a treatment that is suitable for you, together with your doctor.

Everyday life

Symptoms like and difficulty breathing can mean that you’re less fit in daily life or need help with everyday activities. But treating an abnormal heartbeat can be bothersome too – for instance, if you have to regularly take anticoagulants ("blood-thinning" medicines) because of . People who permanently have a (e.g. because of AV block) – and those who have had a defibrillator implanted due to ventricular tachycardia – also have limitations in everyday life.

Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: Executive Summary. Circulation 2018; 138(13): e210-e271.

European Society of Cardiology (ESC), Association for European Paediatric and Congenital Cardiology (AEPC). Guidelines for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death. Eur Heart J 2015; 36(41): 2793-2867.

Glikson M, Nielsen JC, Kronborg MB et al. 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. Europace 2022; 24(1): 71-164.

Hindricks G, Potpara T, Dagres N et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS): The Task Force for the diagnosis and management of atrial fibrillation of the European Society of Cardiology (ESC) Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC. Eur Heart J 2021; 42(5): 373-498.

Kasper DL, Fauci AS, Hauser SL, Longo DL, Jameson JL, Loscalzo J. Harrison's Principles of Internal Medicine. New York: McGraw-Hill; 2015.

Menche N (Ed). Biologie Anatomie Physiologie. München: Urban und Fischer; 2016.

National Institute for Health and Care Excellence (NICE). Atrial fibrillation: diagnosis and management. (NICE Guidelines; No. 196). 2021.

Pschyrembel Online. 2022.

Schmidt R, Lang F, Heckmann M. Physiologie des Menschen: mit Pathophysiologie. Berlin: Springer; 2017.

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. informedhealth.org 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.

Comment on this page

What would you like to share with us?

We welcome any feedback and ideas - either via our form or by gi-kontakt@iqwig.de. We will review, but not publish, your ratings and comments. Your information will of course be treated confidentially. Fields marked with an asterisk (*) are required fields.

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?

Über diese Seite

Created on November 27, 2023

Next planned update: 2026


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

How we keep you informed

Follow us on Twitter or subscribe to our newsletter or newsfeed. You can find all of our films online on YouTube.