Checking your pulse is a useful first step in helping to diagnose atrial fibrillation.
To check your pulse:
At rest, a normal heart rate should be 60 to 100 beats per minute. In atrial fibrillation, the heart rate can often be considerably higher than 100 beats per minute, and each individual beat is erratic.
Heart rhythm charity Arrythmia Alliance has more information about knowing your pulse and how to check it.
Checking and assessing your pulse can give you a good indication of whether you have atrial fibrillation, but a full medical investigation will be needed before a diagnosis can be made.
If atrial fibrillation is suspected, a GP may give you an electrocardiogram (ECG) and refer you to a heart specialist (cardiologist) for further tests.
An electrophysiologist is a cardiologist who specialises in electrical disturbances of the heart.
They can carry out a procedure called catheter ablation to treat your atrial fibrillation.
An ECG is a test that records your heart's rhythm and electrical activity. It's usually carried out in a hospital or GP surgery, takes about 5 minutes, and is painless.
During an ECG, small stickers called electrodes are attached to your arms, legs and chest, and connected by wires to an ECG machine.
Every time your heart beats, it produces tiny electrical signals. An ECG machine traces these signals onto paper.
During an episode of atrial fibrillation, your heart rate will be irregular and over 100 beats per minute.
If you have an episode of atrial fibrillation during an ECG, your abnormal heart rate will be recorded. This will confirm the diagnosis of atrial fibrillation and rule out other conditions.
But often it can be difficult to capture an episode of atrial fibrillation, so you may be asked to wear a small portable ECG recorder.
The recorder will either trace your heart rate continuously over 24 hours or when you switch it on at the start of an episode.
If you have atrial fibrillation, a number of other tests may be carried out, including: