Atrial fibrillation causes

Lesley Dobson / 29 January 2015

The causes of Atrial Fibrillation (AF) vary, and aren’t always entirely clear. However, AF becomes more common with age, and about 10% of people have this condition. Read our guide to find out more.



We all have an in-built pacemaker in our hearts. The pacemaker keeps our hearts pumping at a steady rate by producing regular electrical impulses. AF happens when your pacemaker starts sending out very erratic impulses from different places in your atria. These are the chambers at the top of your heart.

You are more likely to develop AF if you already have other heart conditions. The most common cause of AF is high blood pressure. This is because it can strain the heart muscle.

Read our guide to find out more about blood pressure

Atherosclerosis is another quite common cause. This condition happens when your arteries, especially those supplying blood to your heart, neck and legs become narrowed by fibrous and fatty material. These are called plaques or atheroma. This can cause chest pain (angina) and can cause dangerous conditions including stroke and heart attacks.

Atherosclerosis is one of a number of conditions that affect your blood flow. Together these are known as cardiovascular disease. The other conditions include coronary heart disease, when the plaques block or interfere with the blood supply to your heart.

Read our guide to cardiovascular disease

Other heart conditions that can lead to AF include mitral heart valve disease and congenital heart disease (a condition you are born with). Atrial fibrillation may also be connected with thyroid gland disorders, pneumonia, overactive thyroid, lung cancer and chest infections, and drinking too much alcohol and having too much caffeine (through drinking tea and coffee)

Know your pulse

According to the Atrial Fibrillation Association (AFA), you can find out if you have AF – or heart rhythm disorders generally, by taking your pulse. It is important to have this carried out by a GP or nurse if you are at risk of heart conditions, or have any of the symptoms, but you and your family can take your own pulse as a first step.

1. To find out the resting pulse rate in your writs, first sit down calmly for five minutes. If you have any stimulants, such as caffeine or nicotine, before doing this it will affect your pulse rate. Make sure you have a watch or clock with a second hand on it with you, but not on you.

2. Hold your hand out with your palm facing up and your elbow slightly bent.

3. With your other hand put your index and middle fingers on your wrist, at the base of your thumb. Your fingers should sit between the bone on the edge of your wrist and the tendon attached to your thumb. You may need to move your fingers around a bit to find the pulse. Make sure you keep up firm pressure on your wrist with your fingers, so you can feel your pulse.

4. Count for 30 seconds then multiply by 2 to get your heart rate in beats per minute. If your heart rate is irregular, count for 60 seconds and don’t multiply the amount.

Read our guide to find out more about pulse rate

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.