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Published by Bupa's health information team, June 2008.
This factsheet is for people who have atrial fibrillation or who would like more information about it.
Atrial fibrillation is a type of abnormal heartbeat (an arrhythmia), in which your heart beats in an irregular way, causing it to pump inefficiently. It happens when the electrical impulses controlling your heartbeat become disorganised.
The different types of arrthythmia
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About atrial fibrillation
Your heart is a muscular pump, responsible for delivering blood to the rest of your body. When your heart doesn't beat in a normal way, it can't do this as efficiently.
In atrial fibrillation, the heart beats irregularly, and often too fast. Atrial fibrillation mostly occurs in older people, affecting about four in 100 people over the age of 65, although it can happen in younger people as well.
The electrical impulses in a normal heart and a heart with atrial fibrillation
What happens in atrial fibrillation?
Your heartbeat is controlled by electrical impulses, which travel through the heart making it contract. The impulses travel from the atria (the upper chambers of the heart) to the ventricles (the lower chambers) through an area called the atrioventricular (AV) node. The AV node helps to synchronise the pumping action of the atria and ventricles.
Atrial fibrillation occurs when the electrical impulses in the atria become disorganised, overriding the heart's normal rate and rhythm. This causes the atria to contract in an irregular manner or 'fibrillate'.
The irregular impulses are partly controlled by the AV node. However, they still cause the ventricles to beat irregularly and usually, too fast.
Atrial fibrillation can sometimes be a temporary problem that has come on suddenly, often as a result of another problem, such as a lung infection. It can also come and go, and stop on its own without treatment. However, if it's caused by a structural abnormality in your heart, the problem is likely to be permanent, and you will need ongoing treatment to correct it.
Symptoms of atrial fibrillation
Symptoms may include:
palpitations (you become aware of your heart beating faster or in an irregular way)
chest pain or discomfort
shortness of breath
dizziness and light-headedness
Many people with atrial fibrillation only have mild symptoms, or don't have any symptoms at all.
Complications of atrial fibrillation
Atrial fibrillation can lead to a blood clot forming in your heart. This is because your blood is not able to flow properly through your heart. If a clot forms, it can travel to your brain and cause a stroke. Because of this, people with atrial fibrillation are five times more likely to have a stroke than people without the condition.
If you have atrial fibrillation, you may need anticoagulant medicine (such as aspirin or warfarin) to prevent a clot forming.
Causes of atrial fibrillation
Many conditions that affect the heart or circulation can cause atrial fibrillation, including:
high blood pressure
heart valve disease
heart muscle disease (cardiomyopathy)
coronary heart disease
There are also a number of factors that can result in a temporary, reversible atrial fibrillation, including:
- thyroid diseases
- chest infection
- surgical procedures
However, no cause is found in approximately 12 percent of people with the condition. Atrial fibrillation with no known cause is sometimes called lone atrial fibrillation.
Diagnosis of atrial fibrillation
You should visit your GP if you are having symptoms such as palpitations, chest discomfort or dizziness. Your GP will ask about your symptoms and examine you. He or she may also ask you about your medical history.
Your GP may perform a number of tests, such as checking your blood pressure, listening to the sound of your heartbeat and taking your pulse. If your pulse is irregular, you are likely to have a test called an electrocardiogram (ECG), which traces your heart beat, giving information about the rhythm and electrical activity of your heart.
If your GP suspects you have atrial fibrillation, he or she may refer you to a cardiologist - a doctor specialising in heart conditions. You may need to have further tests carried out at hospital, including:
- a chest X-ray
- blood tests
- an ambulatory ECG - this takes a recording of your heartbeat while you go about your normal daily activities
- an exercise ECG - this takes a recording of your heartbeat while you are exercising on a treadmill or exercise bike
- an echocardiogram - this is a test that uses ultrasound to create a moving image of the inside of your heart
Treatment of atrial fibrillation
Your treatment will be tailored to you, and will depend on your own symptoms and the cause of your atrial fibrillation. Your GP or cardiologist will discuss your treatment options with you.
- If there is an underlying cause for your atrial fibrillation, such as overactive thyroid, this will be treated.
- If you have atrial fibrillation which has come on quite suddenly, your treatment will be aimed at restoring your normal heart rhythm with either medicine or an electrical current (this is called cardioversion).
- If your atrial fibrillation is a permanent problem or comes and goes on its own, you may be offered tablets to try and maintain a normal rhythm, or an ablation - a procedure which can cure atrial fibrillation.
- You may not need any treatment at all if your atrial fibrillation is not bothering you.
- Whichever type of atrial fibrillation you have, you will probably be offered medicines to reduce your risk of getting a blood clot.
There are a number of different types of medicine that can help control atrial fibrillation, including beta-blockers, calcium channel blockers, anti-arrhythmic drugs and a drug called digoxin. They all work in different ways to control your heart rate or restore a normal rhythm.
Your GP or cardiologist may prescribe you a combination of any of these drugs. You may just have to take them for a short period until you get back to normal or until you have a cardioversion procedure, or you may have to take them over the long-term. You may also be given medicine to take just when you get symptoms.
If your atrial fibrillation has come on suddenly, you may be given medicine through a vein to try and get your heart rhythm back to normal. This is called pharmacological cardioversion, and is normally given within the first couple of days of your atrial fibrillation starting.
Medicines to reduce your risk of blood clotting are called anticoagulants. These include warfarin, heparin and aspirin. You will probably be offered one of these drugs in addition to any other treatments you have.
In this treatment, a controlled electrical current is applied to your chest via a machine called a defibrillator, to help restore your heart to its normal rhythm. You will have a general anaesthetic before the procedure begins, so you will be asleep throughout the procedure and feel no pain.
You will probably be given this treatment if your atrial fibrillation has come on recently. It doesn't normally work if you have had atrial fibrillation for a long time.
The following two procedures are only used in selected cases, when your atrial fibrillation has not responded very well to other treatments.
In this procedure, the abnormal areas of your heart are identified and destroyed. A small hole (puncture) is made in the area of your groin, and small tubes called electrode catheters are inserted into one of your veins or arteries. These are then threaded up to your heart. The catheter tip is heated by radio frequency energy, destroying the area that is causing the abnormal rhythm.
The procedure is normally done under a local anaesthetic, which means you will stay awake but feeling from the groin will be blocked, so you will not feel any pain. Catheter ablation can cure atrial fibrillation, but it carries a small risk of serious complication, including stroke - so it is only usually advised if your symptoms are severe and treatment with medicines hasn't worked.
Catheter ablation for atrial fibrillation often involves destroying the AV node, which controls the transmission of impulses from the upper to the lower chambers of your heart. In these cases, you will need a pacemaker implanted to regulate your heart beat. A pacemaker is a small device, usually implanted under the skin in the upper chest. It monitors your heartbeat and produces electrical impulses to correct the heartbeat if it becomes too slow.
You may also be advised to have a pacemaker if your atrial fibrillation is triggered by your heart beating too slowly.
Atrial fibrillation Q&As
See our answers to common questions about atrial fibrillation, including:
- Palpitation. British Heart Foundation, January 2005, Health information series number 14. www.bhf.org.uk
- Simon C, Everitt H, Kendrick T. Oxford Handbook of General Practice. 2nd ed. Oxford: Oxford University Press, 2005:344-345
- Atrial fibrillation - information for the general public. National Institute for Health and Clinical Excellence (NICE), June 2006. www.nice.org.uk
- Atrial fibrillation. Arrhythmia Alliance. www.heartrhythmcharity.org.uk, accessed 9 April 2008
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Dr Tim Cripps DM FRCP, Consultant Cardiologist, specialist in electrophysiology, Bristol Royal Infirmary, and by Bupa doctors. It has also been reviewed by Arrhythmia Alliance. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
Publication date: June 2008