What is atrial fibrillation?
Your heart’s pumping action is controlled by tiny electrical messages produced by a part of the heart called the sinus node. The sinus node is sometimes called your heart’s ‘natural pacemaker’.
Normally, the electrical messages are sent out regularly, with each message telling your heart to contract and pump blood around your body. This is felt as a normal, regular heartbeat, or pulse.
Atrial fibrillation happens because, as well as the sinus node sending out regular electrical impulses, different places in and around the atria (the upper chambers of the heart) also produce electrical messages, in an uncoordinated way. These multiple, irregular messages make the atria quiver or twitch, which is known as fibrillation. This is felt as an irregular and sometimes fast heartbeat, or pulse.
What are the symptoms of atrial fibrillation?
Symptoms can include:
- palpitation (being aware of your heart beat)
- shortness of breath
- dizziness or feeling faint
An irregular pulse could be a sign that you have an atrial fibrillation. However, some people only have mild symptoms, while other people have no symptoms at all.
How can I check for atrial fibrillation?
AF can be detected by feeling the pulse at your wrist. If you are in AF, your pulse will feel irregular and beats may vary in strength. You might also feel this pattern if you have missed beats or extra beats, which are very common and usually nothing to worry about. Some people have AF which comes and goes, so sometimes their pulse may feel normal at times and other times it will be irregular.
Make sure you know your pulse by using our guide to checking your pulse and listening to the sound clips below. If your pulse is irregular or if you’re concerned in any way about your pulse you should make an appointment to see your GP.
Examples of pulse sounds:
What causes atrial fibrillation?
It’s also associated with coronary heart disease. But in many patients no underlying cause can be found. Sometimes AF can be resolved once the underlying condition has been dealt with.
What are the treatments for atrial fibrillation?
Some people with AF need medications to help control the rate and rhythm of their heart. These medications are most commonly beta-blockers and anti-arrhythmic drugs. Occasionally, a procedure such as ablation or cardioversion may be needed.
Can atrial fibrillation lead to a stroke?
AF can increase the risk of a blood clot forming inside the heart. If the clot travels to the brain, it can lead to a stroke. AF increases stroke risk by around four to five times.
However, with appropriate treatment the risk of stroke can be substantially reduced. Anticoagulant (blood thinning) drugs like warfarin and a newer class of drugs called NOACs are the most effective treatments to reduce the risk of stroke in people with AF.
Although AF can greatly increase the risk of stroke, there are other factors that can contribute to a stroke. These include smoking, high cholesterol, high blood pressure, physical inactivity, being overweight and diabetes. The good news is some of these factors are modifiable — this means you can do something about them to reduce your chance of a stroke, whether or not you have AF.
Living with atrial fibrillation
You can find out more about AF by reading our article on living with atrial fibrillation and an inspiring story about pursuing dreams after a diagnosis of atrial fibrillation.
Atrial fibrillation booklet
This booklet describes the heart's normal rhythm, what atrial fibrillation is, diagnosis, complications, and different types of treatment.
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This booklet is also available to download in large print.
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Research into atrial fibrillation and stroke
Over one million people in the UK suffer with an abnormal heart rhythm, including atrial fibrillation which increases the risk of stroke.
Thanks to our supporters, we are the UK’s major independent funder of cardiovascular research, which includes vital stroke and atrial fibrillation research. Our researchers are helping to find people with these conditions and give them the best chance of living long, healthy lives.
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