Atrial fibrillation is a heart condition that causes an irregular and often abnormally fast heart rate. A normal heart rate should be between 60 and 100 beats a minute when you’re resting. You can measure your heart rate by feeling the pulse in your wrist or neck. In atrial fibrillation, the heart rate may be over 140 beats a minute.
What happens in 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 upper chambers of the heart, called the atria, contract randomly and sometimes so fast that the heart muscle cannot relax properly between contractions. This reduces the heart’s efficiency and performance.
This may lead to a number of problems, including dizziness and shortness of breath. You may also be aware of a fast and irregular heartbeat (palpitations) and feel very tired. Some people with atrial fibrillation have no symptoms and are completely unaware that their heart rate is not regular.
Atrial fibrillation is more likely to occur in people with other conditions, such as high blood pressure or atherosclerosis
Atrial fibrillation is generally not life threatening, but it can be uncomfortable and often needs treatment. If your heart rate is over 120 beats per minute you should seek medical attention.
Learn to check your own pulse:
Treatment may involve medication to control the heart rate or rhythm, and medication to prevent a stroke.
Symptoms of Atrial Fibrillation
Some people with atrial fibrillation have no symptoms and it is only discovered during routine tests or investigations for another condition.
The most obvious symptom of atrial fibrillation is a fast and irregular heartbeat, usually over 140 beats a minute. You can determine your heart rate by feeling the pulse in your wrist or neck.
You may also experience:
- chest pain (angina)
The way the heart beats in atrial fibrillation reduces the heart’s efficiency and performance. This can result in low blood pressure and heart failure.
If you notice a sudden change in your heartbeat and have chest pain, see your doctor immediately
Treating Atrial Fibrillation
The treatment of atrial fibrillation varies from person to person and depends on:
- the type of atrial fibrillation
- treatment of any underlying cause
- overall health
Medicines to control Atrial Fibrillation
Medicines called anti-arrhythmics can control atrial fibrillation by:
- restoring a normal heart rhythm
- controlling the rate at which the heart beats
Medicines to reduce the risk of a Stroke
The way the heart beats in atrial fibrillation means that there is a risk of blood clots forming in the heart chambers. If these get into the bloodstream, they can cause a stroke. Depending on your level of risk, you may be prescribed warfarin or aspirin.
Warfarin is an anticoagulant, which means it stops the blood from clotting. There is an increased risk of bleeding in people who take warfarin, but this small risk is usually outweighed by the benefits of preventing a stroke. See this leaflet for more advice on whether to have anti-coagulant therapy or not: Atrial Fibrillation antithrombotic therapy Patient decision aid.
It is very important to take warfarin as directed by the doctor. People on warfarin need to have regular blood tests and, following these, their dose may be changed this is done in our INR clinic.
Many medicines can interact with warfarin and cause serious problems, so check that any new medicines are safe to take with warfarin. Drinking more than moderate amounts of alcohol or drinking cranberry juice can also affect your warfarin and is not recommended.
Aspirin: People with atrial fibrillation who have a low risk of a stroke are likely to be given a low dose of aspirin to take every day instead of warfarin. People who are unable to take warfarin may also be given aspirin instead.