Transient loss of consciousness ('blackouts') in over 16s

Exercise testing

Exercise testing involves having changes in your heart rate, breathing and blood pressure measured while you are doing different levels of exercise. If your blackout happened during some form of physical exercise (and not after exercising), you should be offered exercise testing within 7 days to try to find out why you had a blackout during exercise. This may help with your diagnosis. However, you shouldn't be offered exercise testing if there is a medical reason why this type of test is not suitable for you (for example, if it is suspected you have certain heart conditions). Your healthcare professional should discuss with you what kind of exercise you normally do, and how much is appropriate for you until you have had further assessment and have been told that it is fine to exercise again.

If testing shows how exercise triggers your blackout, you should be offered further tests or treatments according to your particular condition.

Ambulatory ECG

An ambulatory ECG is a test that uses a device to monitor and record your heart activity over a period of time to find out if you have an abnormal heart rhythm. This device will not stop you from having another blackout, and is only used to record your heart activity.

You should be offered this test if the specialist team thinks that your blackout may have been caused by a change in your heartbeat (also known as a 'cardiac arrhythmia') or if they are not certain what caused your blackout.

Whether you are offered a device that you wear, or a small device that is implanted under the skin during a hospital operation, will depend on your history and how often you have a blackout. If you are offered a device that is implanted under your skin, you and your family or carers should be shown how to use it. If you have another blackout after the device has been fitted, you should be advised to see a member of the specialist team as soon as possible so that the details that have been recorded by the device can be checked.

Carotid sinus massage

If the cause of your blackout is unexplained and you are aged 60 or over, or if the specialist team thinks you may have had a blackout due to an over-sensitive artery in your neck (this is also known as 'carotid sinus syncope'), you should be offered a test called carotid sinus massage. This test involves a trained healthcare professional pressing on an artery in your neck while watching an ECG monitor, and this may cause a blackout. Reproducing your blackout may help to show that it is caused by a drop in your heart rate triggered by pressure on the artery in your neck. If this test does not lead to a diagnosis, you should then be offered an ambulatory ECG (see above).

Tilt test

A tilt test involves having your heart rate and blood pressure monitored while being tilted (head up) on a special examination couch in the hospital to see if this leads to you having a blackout. You may be offered this test if the specialist team knows you keep having blackouts and thinks they are affecting your quality of life or could cause you harm.

Cardiac imaging and other tests

If it is suspected that you have a condition known as 'structural heart disease' (where the structural parts of your heart, such as the muscle or valves, are abnormal), you may be offered tests such as cardiac imaging where pictures of your heart are taken and examined.

You may be offered some other tests that the specialist thinks will help with your diagnosis, for example, if there is an inherited heart condition in your family, or any family members have died from heart problems at a young age (under 40).