How Is Atrial Fibrillation Diagnosed?

Pulse check

Checking your own pulse is an easy way to detect a potential heart-related condition such as atrial fibrillation (AF), especially if you have any of the signs or symptoms. To check your pulse, you need to follow the steps below:1-3

  1. Be seated 5 minutes prior to the time you plan to check your pulse.
  2. Make sure you are in the vicinity of a clock or you have a watch (if you only have a watch, place it on a stable surface where you can see it).
  3. Avoid taking any stimulants that may alter your heart rate such as caffeine or nicotine before conducting this test.
  4. Hold your left hand out with your palm facing up and your elbow slightly bent.
  5. Place the index and middle fingers of your right hand on your left wrist, at the base of your thumb. Your fingers should sit between the bone on the edge of your wrist and the tendon attached to your thumb.
  6. Move the fingers around until you can find the pulse on your left wrist (you may need to apply a slight pressure on your left wrist with your fingers in order to feel the pulse).
  7. Use the second hand on your clock or watch to count the number of beats in 30 seconds. Multiply this number by 2 and this will give you the number of beats per minute.

A normal resting heart rate is usually between 60 and 100 beats per minute, but in patients with AF this number can be significantly higher.1 If the number of beats per minute is significantly higher than 100, significantly lower than 60, or if you have an irregular heartbeat, you should seek medical attention.

Electrocardiogram (ECG)1,2

An ECG is a non-invasive and pain-free test that monitors the electrical activity and rhythm of your heart.1 It is commonly undertaken at a GP surgery or local hospital and usually takes about 5 minutes to complete.

When completing an ECG, your doctor will attach stickers containing electrodes to various parts of your body. These stickers are connected by wires, which feed into an ECG machine. This machine detects the electric activity generated by each heartbeat and traces this onto paper. To diagnose AF and rule out any similar conditions of the heart, the pattern of your heartbeat must be erratic and over 100 beats per minute.

If you are frequently experiencing symptoms of AF (particularly palpitations), your doctor may suggest using an ambulatory ECG monitor to monitor the activity of your heart for 24 hours or more. This can be used to diagnose a specific form of AF known as paroxysmal AF, which is ‘intermittent’, or ‘episodic’ AF.1 The ambulatory ECG monitor will keep track of your heart’s beating pattern and your doctor can download the results from the monitor once you have returned it to them. 

Picture showing the phases of an ECG


If your doctor diagnoses you with AF, they may perform an echocardiograph on you, which is an ultrasound scan used to determine the structure and functioning of your heart and valves.1 It is also a non-invasive and painless test that can reveal any heart abnormalities so that your doctor can take further action, if needed.4

Differential diagnosis

The symptoms common in AF can also be caused by other conditions such as:

  • Atrial flutter – similar to AF. The difference between atrial flutter and AF is that in AF the top chambers of the heart (atria) do not beat regularly. In atrial flutter the atria do beat regularly – just a lot faster than they should5,6
Diagram of the heart.

A full medical examination is required by your doctor before diagnosing AF and you may be referred to a doctor who specializes in heart conditions (a cardiologist) for further tests.

What factors increase the risk of AF?

There are certain factors that increase the likelihood that AF will develop. These are:7,8

  • Hypertension (high blood pressure)
  • Diabetes
  • Atherosclerosis
  • Heart failure
Previous: Signs and symptoms
Next: Treatments