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Atrial fibrillation symptoms

Lesley Dobson / 29 January 2015 ( 21 May 2019 )

Atrial Fibrillation (AF) is a condition that causes heart rhythm disturbance. In fact it is the most common heart rhythm disturbance in the UK. Read our guide to find out more about the symptoms.

Mature woman asleep in a garden chair
Being tired is common symptom of atrial fibrillation and can vary in degrees of severity

Estimates of the number of people affected by AF vary from 800,000 to one million in the UK. However, the real number may be more, because not all cases are diagnosed.

The causes of atrial fibrillation

Some people in the early stages of AF don’t have any symptoms, so don’t realise that they have AF. This is known as ‘asymptomatic ‘AF, and may only be discovered when the person is having tests for a different condition.

There are three different categories of AF, according to the Atrial Fibrillation Association.

1. Paroxysmal AF (PAF) has episodes that stop within seven days without any treatment.

2. People with Persistent AF have episodes that last for longer than seven days, or less when treated.

3. Permanent or longstanding persistent AF is continuous AF that has been happening for over a year.

Symptoms of atrial fibrillation

The most noticeable symptoms of AF are an unusually fast heart rate, and irregular heart beats (palpitations).

Our hearts normally beat at 60 to 100 beats a minute, when you’re at rest. But if you have AF your heart may beat 140 times a minute, or more.

Palpitations are a common symptom. Palpitation generally means being aware that something unusual is happening with your heart – it may feel as if your heart is thumping.

People with AF can have very irregular heart rhythm, with no pattern to their heartbeats.

For much of the time, if you are healthy, you aren’t aware of your heart beating, unless you have been more energetic than you usually are, or have had a sudden shock.

As a result of your abnormal heartbeat you may feel other symptoms. Being tired is common, and can vary from not having as much energy as usual, to being exhausted much of the time.

You may feel breathless, varying from mild to more severe, which develops over a relatively short period of time, from minutes to a few days.

Other symptoms include feeling dizzy or light headed, and even blacking out.

You may have chest pain or feel uncomfortable across your chest (also known as angina). This can be caused by the way AF affects the heart, making it beat irregularly and inefficiently. This can lead to low blood pressure. It can even cause heart failure. If you notice that your heart beat has changed, and you develop chest pain, see a doctor straight away.


The opinions expressed are those of the author and are not held by Saga unless specifically stated. The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.