Diagnosis

See your GP immediately if you have chest pain and notice a sudden change in your heartbeat.

Checking your pulse

Follow the four steps below to check your pulse.

• sit down for five minutes and avoid smoking or drinking caffeine before taking the reading
• hold your left hand out with your palm facing up and elbow slightly bent
• firmly place the index and middle finger of your right handon your left wrist, at the base of the thumb (between the wrist and the tendon attached to the thumb)
• using the second hand on a clock or watch, count the number of beats for 30 seconds, and then double that number to get your heart rate in beats per minute

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 further information on knowing your pulse and how to check it (PDF, 113kb) .

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.

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 (particularly if you're experiencing other symptoms of atrial fibrillation )

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

If atrial fibrillation is suspected, your GP may give you an electrocardiogram (ECG) and refer you to a heart specialist (cardiologist) for further tests.

A cardiologist who specialises in electrical disturbances of the heart is known as an electrophysiologist. They can carry out a procedure called catheter ablation to treat your atrial fibrillation.

Electrocardiogram (ECG)

An ECG is a test that records your heart's rhythm and electrical activity. It's usually carried out in a hospital orGP surgery, takes about five minutes and is painless.

During an ECG, small stickers, called electrodes, areattached 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.

However, as it can often be difficult to capture an episode of atrial fibrillation, 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 startof an episode.

Other tests

According to guidance produced by the National Institute for Health and Care Excellence (NICE) , if you have atrial fibrillation, a number of other tests should be carried out. These include:

• an echocardiogram which is an ultrasound scan of the heart; it can help to identify any other heart-related problems, and is used to assess the structure and function of the heart and valves
• a chest X-ray which can help to identify any lung problems that may be causing atrial fibrillation
• blood tests which can highlight anaemia , problems with kidney function, or an overactive thyroid gland (hyperthyroidism)