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Atrial Fibrillation

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What is Atrial Fibrillation?

Atrial Fibrillation (also known as AF) is the most common type of heart arrhythmia (an irregular heartbeat).

Atrial fibrillation refers to:

Atrial: involving the “atria”, the upper chambers of your heart

Fibrillation: rapid, irregular contractions of the muscles

In atrial fibrillation, the electrical signals in the chambers of your heart become chaotic and disorganised, making them contract very rapidly and in an irregular way.

This fast, irregular rhythm prevents the heart from pumping effectively, which can mean that the blood does not circulate properly around your body.

Some types of AF can be treated by a process called cardioversion. This is a procedure which uses a controlled electric shock to you heart, from a machine called a defibrillator, to get your heart rhythm back to normal.

The different types of Atrial Fibrillation

  • Paroxysmal atrial fibrillation comes and goes and usually stops within 48 hours without any treatment.
  • Persistent atrial fibrillation lasts for longer than 7 days. It can be treated with drugs or by cardioversion to help the heart return to beating normally.
  • Permanent or chronic atrial fibrillation lasts for a long time (usually longer than a year). Cardioversion is rarely used in this case and is usually unsuccessful. Drug treatment can be used to help control your heart rate.
  • Acute-onset atrial fibrillationis an episode of AF that either starts suddenly for the first time or is worse than existing symptoms. This kind of AF can cause potentially dangerous symptoms (e.g. a very fast heart rate) which may need to be treated in hospital.

Symptoms of Atrial Fibrillation

Some people have no symptoms, and AF may only be discovered when a nurse or doctor feels your pulse and finds it to be fast and irregular. In other cases, poor blood circulation can cause some or all of:

  • Dizziness
  • Tiredness
  • Chest pain
  • Shortness of breath
  • Palpitations (increased awareness of your heartbeat, or a sense that your heart is beating too fast or too hard)

If you notice a sudden change in your heartbeat and have chest pain, look for medical advice as soon as possible.

What are the risks of Atrial Fibrillation?

  • Stroke: The main risk of AF is that it can lead to a stroke. When the atria are working poorly, they may not empty completely, leaving a pool of blood in the chamber. This blood can become sludgy and may clot. If a blood clot enters the blood stream it can lead to a stroke. You will usually be prescribed a blood thinning drug (e.g. warfarin, heparin or aspirin) to try and prevent clots like this from forming.
  • Heart failure: Over time, AF can weaken the heart. When the heart muscle cannot meet the body’s demands for blood and oxygen, the body can develop many different symptoms. When this happens, it is referred to as heart failure because of the failure of the heart to work efficiently.

The risks caused by atrial fibrillation are higher for women than for men, although it is not clear why this is.

Causes of Atrial Fibrillation

Sometimes AF develops without a clear cause. However, sometimes AF can develop alongside other medical conditions such as:

  • Heart conditions like:
    • High blood pressure
    • Coronary heart disease (especially if you have had a heart attack or heart surgery)
    • Heart valve disease
    • Congenital heart disease
    • Cardiomyopathy
  • Lung conditions like:
    • Pulmonary embolism
    • Asthma
    • Emphysema
    • Chronic obstructive pulmonary disease (COPD)
    • Pneumonia
    • Lung cancer
  • An overactive thyroid gland
  • Diabetes
  • Imbalances of the chemicals in your blood e.g., potassium, calcium

What triggers Atrial Fibrillation?

AF may be triggered, in whole or in part, by:

  • Drinking excessive amounts of alcohol, particularly ‘binge drinking’ (where you drink a very large amount of alcohol in a short time)
  • Being significantly overweight or underweight
  • Drinking a lot of caffeine, which is found in coffee, tea, and energy drinks, or taking caffeine pills.
  • Taking recreational drugs, particularly those that stimulate the heart.
  • Smoking

Maintaining a healthy lifestyle

Learning to recognise your individual trigger factors, so that you can reduce or avoid them, can sometimes help to minimise your symptoms of AF. This could mean that you make significant changes to your way of living. You may need to make changes in your daily habits, like stopping smoking or cutting out alcohol.

This can be a difficult transition. If you tell your loved ones that you are making these changes, they are often able to support you and get involved. Habit change is often easier with someone to help you. Make sure that you get into healthy habits: drink plenty of water every day, eat healthily, and stay active wherever possible.

Visit our Living with a Heart Condition section for more information about how to manage your condition at home, how to stay well, and how to reduce your risk of future heart conditions.

Call our Advice Line for free on 0808 801 0899 or text NURSE to 66777 if you’d like information on support groups, AF or even just a trained listening ear. We’re here to support you and help you to build a healthier life.

This page was last updated on May 2, 2023 and is under regular review. If you feel anything is missing or incorrect, please contact to provide feedback.

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