Atrial fibrillation (AF) is a heart condition that causes an irregular and often abnormally fast heart rate. It is one of the most common forms of abnormal heart rhythm and a major cause of stroke.
What is atrial fibrillation?
When the heart beats normally, its muscular walls contract (tighten and squeeze) to force blood out and around the body. They then relax, so the heart can fill with blood again. This process is repeated every time the heart beats.
In atrial fibrillation, the heart's upper chambers (atria) contract randomly and sometimes so fast that the heart muscle can't relax properly between contractions. This reduces the heart's efficiency and performance.
Atrial fibrillation occurs when abnormal electrical impulses suddenly start firing in the atria. These impulses override the heart's natural pacemaker, which can no longer control the rhythm of the heart. This causes the person to have a highly irregular pulse rate.
The cause isn't fully understood, but it tends to become more common as you get older. It may be triggered by certain situations, such as drinking excessive amounts of alcohol or smoking.
Read more about the causes of atrial fibrillation.
What are the symptoms of atrial fibrillation?
You may be aware of noticeable heart palpitations, where your heart feels like it's pounding, fluttering or beating irregularly, often for a few seconds or, in some cases, a few minutes.
Sometimes, atrial fibrillation doesn't cause any symptoms and a person is completely unaware that their heart rate isn't regular.
Read more about the symptoms of atrial fibrillation.
How can I check for atrial fibrillation?
A normal heart rate should be regular and between 60 and 100 beats per minute when resting.
In atrial fibrillation, the heart rate is irregular and can sometimes be very fast. In some cases, it can be considerably higher than 100 beats per minute.
You can measure your heart rate by feeling the pulse in your neck or wrist. Use the British Heart Foundation guide to make sure you know how to check your pulse.
When to see your GP?
You should make an appointment to see your GP if:
- you notice a sudden change in your heartbeat
- your heart rate is consistently lower than 60 or above 100 - particularly if you're experiencing other symptoms of atrial fibrillation, such as dizziness and shortness of breath
See your GP as soon as possible if you have chest pain.
Treating atrial fibrillation
Most people with AF will require an anticoagulant, but a small number of these won't as it depends on the risk.
Anticoagulation means that you take a medicine to reduce the chance of a blood clot forming and having an AF-related stroke.
If I've got AF, what can I do to reduce the risk of having 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.
Atrial fibrillation increases the risk of a stroke by around four to five times. However, with appropriate treatment the risk of stroke can be substantially reduced.
Most people with AF will require an anticoagulant, but a small number won't, as it depends on risk.
Depending on your level of risk, you may be prescribed warfarin or a newer type of anticoagulant, such as dabigatran, rivaroxaban, apixaban or edoxaban.
They work by slowing down the blood's blotting process, and reduce the risk of stroke by nearly two thirds for people with AF. In other words, these treatments can prevent about six out of ten strokes.
Your GP or pharmacist will be able to discuss your options with you.
Aspirin isn't recommended to prevent strokes caused by AF, but is still used for other heart conditions.
Although AF can greatly increase the risk of stroke, there are other factors that can contribute to a stroke, including:
- high cholesterol
- high blood pressure
- physical inactivity
- being overweight
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.