Arrhythmia (abnormal heart rhythm)

An arrhythmia is an abnormal heart rhythm. The heart may beat too slowly, too quickly, or irregularly. Most people with an abnormal heart rhythm can lead a normal life if it's diagnosed and treated. This page has information on common types of arrhythmia and symptoms linked to the condition.

Symptoms of arrhythmias 

Symptoms of arrhythmias include:

However, having these symptoms does not always mean you have a heart rhythm problem. You should see your GP if you have any of these symptoms.

Common types of arrhythmia 

The most common types of arrhythmia include:

  • atrial fibrillation (AF) – this is the most common type, where the heart beats irregularly and faster than normal
  • supraventricular tachycardia/ventricular tachycardia  – episodes of abnormally fast heart rate at rest
  • bradycardia – the heart beats more slowly than normal
  • heart block – the heart beats more slowly than normal and can cause people to collapse
  • ventricular fibrillation – a rare, rapid and disorganised rhythm of heartbeats that rapidly leads to loss of consciousness and sudden death if not treated immediately
  • extrasystoles/ectopic beats (extra heartbeats)

Arrhythmias can affect all age groups. However, atrial fibrillation is more common in older people.

Drinking alcohol in excess or being overweight increases your risk of developing atrial fibrillation.

You may also be at risk of developing an arrhythmia if your heart tissue is damaged because of an illness – for example, if you have had a heart attack or have heart failure.

Atrial fibrillation is a common cause of stroke. Having atrial fibrillation means your risk of stroke is five times higher than for someone whose heart rhythm is normal.

Certain types of arrhythmia occur in people with severe heart conditions. These can cause sudden cardiac death. Some of these deaths could be avoided if the arrhythmias were diagnosed earlier.

Common triggers for an arrhythmia include:

  • viral illnesses
  • alcohol, tobacco
  • changes in posture
  • exercise
  • drinks containing caffeine
  • certain over-the-counter and prescribed medications  
  •  illegal recreational drugs

Other causes of arrhythmia

Lowering your risk of an arrhythmia 

It is not always possible to prevent an arrhythmia developing. However, a healthy lifestyle can lower your risk of developing a heart condition.

Treatment aims to prevent future episodes. You can also make lifestyle changes so you avoid some of the triggers for your heart rhythm problem.

Your heart's electrical system 

The heart's rhythm is controlled by electrical signals. An arrhythmia is an abnormality of the heart's rhythm. It may beat too slowly, too quickly, or irregularly.

These abnormalities range from a minor inconvenience or discomfort to a potentially fatal problem.

Diagnosing arrhythmias 

If your symptoms persist or there's a history of unexplained sudden death in your family, it's important for your GP to refer you to a heart specialist.

The most effective way to diagnose an arrhythmia is with an electrical recording of your heart rhythm called an electrocardiogram (ECG). If the ECG doesn't find a problem, you may need further monitoring of your heart.

This may involve wearing a small portable ECG recording device for 24 hours or longer. This is called a Holter monitor or ambulatory ECG monitoring.

If your symptoms seem to be triggered by exercise, an exercise ECG may be needed to record your heart rhythm while you are using a treadmill or exercise bike.

Other tests used in diagnosing arrhythmias include:

  • cardiac event recorder – a device to record occasional symptoms over a period of time whenever you have them
  • electrophysiological (EP) study – a test to find problems with the electrical signals in your heart by passing soft wires up a vein in your leg and into your heart while you are sedated
  • echocardiogram (echo) – an ultrasound scan of your heart

Treatment for arrhythmias 

How your arrhythmia will be treated will depend on whether it is a fast or slow arrhythmia or heart block. Any underlying causes of your arrhythmia, such as heart failure, will need to be treated as well.

The treatments used for arrhythmias include:

  • medication – to stop or prevent an arrhythmia or control the rate of an arrhythmia
  • cardioversion – a treatment that uses electricity to shock the heart back into a normal rhythm while you are anaesthetised or sedated
  • catheter ablation – a keyhole treatment under local or general anaesthetic that carefully destroys the diseased tissue in your heart that causes the arrhythmia
  • pacemaker – a small device containing its own battery that is implanted in your chest under local anaesthetic; it produces electrical signals to do the work of the natural pacemaker in your heart to help it beat at a normal rate
  • ICD – a device similar to a pacemaker that monitors your heart rhythm and shocks your heart back into a normal rhythm whenever this is needed

Staying safe with an arrhythmia 

If you have an arrhythmia that affects your driving, you must tell the Driver & Vehicle Agency (DVA).

If your job involves working at height or with machinery that could be dangerous, you will need to stop work at least until your arrhythmia is diagnosed or you get treatment for your underlying condition. Get advice from your GP or cardiologist.

The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was reviewed January 2019

This page is due for review October 2021

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