Some people have an irregular, and often rapid, heartbeat (known as atrial fibrillation), which makes them more likely to experience a stroke. This condition is often associated with other diseases that affect the heart, such as high blood pressure, an overactive thyroid gland, heart failure, faulty heart valves, lung disease, and stimulant or alcohol abuse. (1)


How common is an irregular heartbeat?

Millions of people worldwide have a heart that does not beat at a steady, normal pace. It is estimated that atrial fibrillation increases a person’s risk of having a stroke by four to six times on average. The risk increases with age and, in people over 80, irregular heartbeat is the direct cause of one in four strokes. (1) Studies suggest that the total number of people affected by atrial fibrillation in Europe will rise to 17.9 million by 2060. (2)


What are the symptoms of an irregular heartbeat?

Some people don’t have any symptoms and are unaware of their condition until it is revealed during a physical examination. Others may experience heart palpitations (such as pounding or fluttering), shortness of breath, chest pain, extreme tiredness, general weakness, dizziness and confusion. (1)


What causes an irregular heartbeat?

The exact cause of atrial fibrillation isn’t known. It could be caused by several factors. However, we do know that it is more common with age and is more likely to affect people with previous heart problems. Some pre-existing medical conditions are also associated with atrial fibrillation, including diabetes, hyperthyroidism and some lung conditions. The overall number of men and women with atrial fibrillation is similar, but around 60% of AF patients aged over 75 are women and therefore, older females who have atrial fibrillation also have a higher risk of stroke (3).


How can this lead to a stroke?

When the two upper chambers of the heart (atria) are out of sync with the two lower chambers (ventricles), this causes an irregular heartbeat (atrial fibrillation) which can lead to blood clots. These clots can travel to the blood vessels in the brain, causing stroke. (4) An abnormal heartbeat is estimated to make someone 3–5 times more likely to have a stroke. It is also associated with more severe strokes, leading to a higher chance of death and disability. (5)


How is an irregular heartbeat diagnosed and treated?

Sometimes simply checking your pulse can detect atrial fibrillation. If your pulse rate is lower than 60 or higher than 100, your doctor may recommend blood tests or an electrocardiogram (ECG), where sensors are attached to skin and heart electrical activity is registered. If an irregular heartbeat is detected, you will be prescribed medications and other interventions to try to alter its pattern.

People with atrial fibrillation who have a medium to high risk of stroke may be prescribed novel oral anticoagulants (NOACs). These drugs stop the blood from forming clots and travelling to the brain, leading to stroke (6).


Can an irregular heartbeat be prevented?

Atrial fibrillation increases the risk of stroke by around 500%. Novel oral anticoagulants (NOACs) are now recommended as the most effective therapy for preventing a stroke due to atrial fibrillation, followed by Vitamin K antagonists (VKAs), which affect how the liver uses Vitamin K to regulate blood clotting. (7)

As well as taking anticoagulant medicine, you can reduce the chance of developing an irregular heartbeat, which is a known risk factor for stroke, by leading a healthy lifestyle. This includes managing your weight, reducing the fat in your diet and lowering alcohol consumption. (8)


If you’ve had a stroke, you’re at greater risk of having another one

At least 1 in 4 people who had a stroke will have another stroke within 5 years (9)

Finding out what caused your stroke will help your physician take steps to minimise the risk of having another one.

People with atrial fibrillation are 5 times more likely to have a stroke (10). However, Atrial fibrillation is hard to detect because it can happen infrequently and you may not feel any symptoms. If detected, atrial fibrillation is treatable.

You may be asked to wear a portable heart monitor for several days to try to detect atrial fibrillation but in some cases a long-term option like an insertable heart monitor may be needed. By monitoring your heart continuously, an insertable heart monitor is more likely to give your doctor a complete picture of your heart health.

Insertion of an insertable heart monitor only takes a few minutes and does not require general anesthesia.


  2. Morillo CA, Banerjee A, Perel P, Wood D, Jouven X. Atrial fibrillation: the current epidemic. J Geriatr Cardiol. 2017;14(3):195-203. doi:10.11909/j.issn.1671-5411.2017.03.011.
  6. Jan Steffel et al. 2021 European Heart Rhythm Association Practical Guide on the Use of Non-Vitamin K Antagonist Oral Anticoagulants in Patients with Atrial Fibrillation. Europace (2021) 23, 1612–1676. doi:10.1093/europace/euab065.
  7. AF association, SAFE et al. Oral Anticoagulant Therapy Booklet
  9. Mohan KM, et al. Stroke. 2011;42:1489-1494.

  10. Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation as an independent risk factor for stroke: The Framingham Study. Stroke. August 1991;22(8):983-988.


Updated December 2023

Next review 2024