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Heart disease health centre

Atrial fibrillation - Diagnosing atrial fibrillation

NHS Choices Medical Reference

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If you notice a sudden change in your heartbeat and you have chest pain, see your GP straight away.

Checking your pulse

Follow these four steps to check your pulse:

  • avoid taking any caffeine or other stimulants, then sit down for 5 minutes
  • hold your hand out, palm up, with your elbow slightly bent
  • place your index and middle fingers on your wrist, at the base of your thumb
  • count the beats for 30 seconds, then double that number to get your heart rate in beats per minute

A normal heart rate should be between 60 and 100 beats a minute when you are resting.

You can also download a leaflet from the Arrythmia Alliance on how to check your pulse (PDF, 113kb).

Feeling your pulse can give a strong indication of whether you have atrial fibrillation, but a full medical investigation is needed before a diagnosis can be made.

When to see your GP

Make an appointment to see your GP if:

  • you notice a sudden change in your heartbeat
  • your heart rate is consistently lower than 60 or above 100 - especially if you are experiencing other symptoms of atrial fibrillation

See your GP as soon as possible if you have chest pain.

If your GP suspects atrial fibrillation, you may be given an electrocardiogram and referred to a heart specialist, known as a cardiologist, for more tests. 

A cardiologist who deals exclusively with electrical disturbances of the heart is called an electrophysiologist and this type of cardiologist can perform an operation (catheter ablation) to treat your atrial fibrillation.


An electrocardiogram (ECG) is a test that records the rhythm and electrical activity of your heart.

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 on paper. During atrial fibrillation, your heart rate is irregular and may be over 140 beats a minute.

An ECG is usually carried out in a hospital or GP surgery. It takes about five minutes and is painless. 

If you have the test during an attack of atrial fibrillation, the ECG will record your abnormal heart rate. This will confirm the diagnosis of atrial fibrillation and rule out other conditions.

However, it may be difficult to capture an attack, so you may be asked to wear a small, portable electrocardiogram recorder. This will either trace your heart rate continuously over 24 hours, or when you switch it on at the start of an attack.


An echocardiogram is an ultrasound scan of the heart. It can help identify any other heart problems and assess the structure and function of the heart and valves.

Chest X-ray

A chest X-ray will identify any lung problems that may have caused the atrial fibrillation.

Blood tests

Blood tests can also be useful in the diagnosis. They may show anaemia, which may be complicating the situation, problems with kidney function or hyperthyroidism (overactive thyroid gland).

Medical Review: July 07, 2013
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