Patient information from BMJ

Atrial fibrillation: what is it?

Last published:Aug 05, 2021

Atrial fibrillation can be alarming, especially the first time it happens. Your heart beats very fast. It may go away on its own, or you may need treatment to make your heart beat smoothly again.

What happens?

Atrial fibrillation is when your heart doesn't beat regularly. For some people it lasts only a short time - from a few minutes to a day or two. For others it comes and goes and can last a long time.

Your heartbeat is controlled by electrical signals from a 'pacemaker' in your heart. If you have atrial fibrillation the pacemaker sends out too many signals at once. Your heart rate will probably be fast and not have its regular pattern.

Men are more likely than women to get atrial fibrillation. It's also more common if you:

• are older

• have high blood pressure, or

• have heart problems.

Atrial fibrillation can also sometimes be linked to drinking a lot of alcohol, or to medical problems such as:

• diabetes

• lung diseases, and

• problems with your thyroid gland.

Atrial fibrillation can make you more likely to have a stroke. But there are good treatments to help prevent this.

What are the symptoms?

The most common symptom is feeling your heart racing.

But this doesn't happen to everyone. Some people only find out that they have atrial fibrillation after they have a stroke. Signs of a stroke include feeling numb down one side of your body, problems with your vision, and having trouble speaking or swallowing.

If you have atrial fibrillation you might also feel chest pain, get breathless, and feel dizzy. If you get these symptoms you should call an ambulance or go to hospital straight away. They could also be signs of a heart attack.

Tests for atrial fibrillation include:

• An ECG (electrocardiogram), which shows how your heart is beating

• An echocardiogram, which is an ultrasound scan to produce a picture of your heart.

What will happen to me?

More than half the people who have short-term atrial fibrillation get their normal heart rhythm back in less than two days without any treatment. But for some people it's a long-term condition.

Atrial fibrillation increases your risk of having a stroke. But having treatment can help reduce this risk. To learn more, see Atrial fibrillation: what treatments work?