Key facts
- Atrial fibrillation causes an irregular heart rhythm originating in the upper chambers of the heart.
- Some people notice palpitations, breathlessness or tiredness, while others have no obvious symptoms.
- An ECG is commonly used to confirm whether atrial fibrillation is present.
- High blood pressure, increasing age and several heart conditions can increase the likelihood of atrial fibrillation.
- Atrial fibrillation can increase the risk of blood clots and stroke, so confirmed AF needs appropriate medical assessment and follow-up.
Signs and symptoms
Atrial fibrillation may cause a racing, fluttering or irregular heartbeat.
Other symptoms can include shortness of breath, dizziness, tiredness, reduced exercise tolerance or chest discomfort. Some people have no noticeable symptoms and the rhythm is discovered during a routine examination or ECG.
Risk factors
Increasing age
High blood pressure
Coronary heart disease or other heart conditions
Heart valve disease
Overactive thyroid
Obesity or obstructive sleep apnoea
Heavy alcohol use
Previous heart surgery or other cardiovascular disease
Common causes
Atrial fibrillation occurs when the electrical signals controlling the upper chambers of the heart become disorganised, causing the atria to beat irregularly.
It can occur alongside high blood pressure, coronary heart disease, heart valve problems, thyroid disease and other cardiovascular conditions. Sometimes no single underlying cause is identified.
How it is checked
Assessment usually begins with your symptoms, pulse and medical history. An electrocardiogram (ECG) can record the heart rhythm and is commonly used to confirm atrial fibrillation.
If episodes come and go, longer heart-rhythm monitoring may sometimes be needed. Blood tests and other investigations may also be considered to look for contributing conditions and assess overall cardiovascular health.
Assessment and investigations
Electrocardiogram (ECG)
An ECG records the electrical activity of the heart and can confirm atrial fibrillation when the abnormal rhythm is present during the recording.
Thyroid Function Test
Thyroid blood tests may be useful because an overactive thyroid can contribute to atrial fibrillation or a fast heart rhythm.
Selected blood tests
Blood tests may be used to look for factors that can affect heart rhythm or influence treatment decisions, depending on the individual clinical situation.
When to see a doctor
Arrange medical assessment if you repeatedly notice an irregular or racing heartbeat, unexplained palpitations, dizziness, breathlessness or a decline in exercise tolerance.
Seek urgent medical attention for severe chest pain, fainting, severe breathing difficulty or sudden symptoms suggestive of a stroke, such as facial weakness, arm weakness or difficulty speaking.
Frequently asked questions
Can atrial fibrillation happen without symptoms?
Yes. Some people have no noticeable symptoms and atrial fibrillation is discovered when an irregular pulse is noticed or an ECG is performed for another reason.
Are heart palpitations always atrial fibrillation?
No. Palpitations can occur for many reasons, including stress, caffeine, medicines, thyroid problems and other heart rhythms. An ECG or other rhythm recording is needed to determine what the heart is actually doing.
How is atrial fibrillation diagnosed?
An ECG is commonly used to confirm atrial fibrillation. If the abnormal rhythm occurs only occasionally, longer rhythm monitoring may sometimes be needed to capture an episode.
Why is atrial fibrillation important?
Atrial fibrillation can affect how efficiently the heart beats and can increase the risk of blood clots and stroke in some people. Once AF is confirmed, the individual’s stroke risk and overall heart health need to be assessed.