Condition: Blackouts and Fainting

Fainting or a blackout is a temporary loss of consciousness.


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What is fainting or a blackout?

Fainting or a blackout is a temporary loss of consciousness. If someone loses consciousness for a few seconds or minutes, they are often said to have had a blackout.

What causes fainting or a blackout?

Most unexplained blackouts are caused by syncope

Many people, including doctors, assume that blackouts are due to epileptic seizures, but much more commonly they are due to syncope (pronounced sin-co-pee) – a type of blackout which is caused by a problem in the regulation of blood pressure or sometimes with the heart. Up to 40% of the population will lose consciousness at some point in their life due to syncope. Syncope can affect all age groups but the causes vary with age, and in older adults multiple causes often exist.

Many syncopal attacks only require reassurance from your GP

Many syncopal attacks require only explanation and reassurance from a GP or trained nurse regarding the likely absence of anything being seriously wrong. Consultation with a specialist will be necessary, though, if the cause of the syncope remains uncertain or if there are particularly concerning symptoms or there is a family history of a heart condition.

There are three major reasons for why people may experience a blackout(s):

  • Syncope: a sudden lack of blood supply to the brain. Syncope is caused by a problem in the regulation of blood pressure or by a problem with the heart.
  • Epilepsy: an electrical ‘short-circuiting’ in the brain. Epileptic attacks are usually called seizures. Diagnosis of epilepsy is made by a neurologist.
  • Psychogenic blackouts: resulting from stress or anxiety. Psychogenic blackouts occur most often in young adults. They may be very difficult to diagnose. ‘Psychogenic’ does not mean that people are ‘putting it on’. However there is often underlying stress due to extreme pressure at school or work. In exceptional cases it may be that some people have experienced ill treatment or abuse in childhood.

Misdiagnosis is common but avoidable:

  • Many syncopal attacks are mistaken for epilepsy.
  • However epilepsy only affects slightly less than 1% of the population.
  • UK research has shown that approximately 30% of adults and up to 40% of children diagnosed with epilepsy in the UK do not have the condition.
  • Many elements of a syncopal attack, such as random jerking of limbs, are similar to those experienced during an epileptic seizure.
  • It can be difficult to tell the causes of the blackout apart.

Syncope causes falls:

  • Syncope causes a significant number of falls in older adults, particularly where the falls are sudden and not obviously the result of a trip or slip.
  • Many older adults will only recall a fall and will not realise they have blacked out.
  • Greater awareness of syncope as a cause of falls is key to effective treatment and prevention of recurring falls.

How are blackouts investigated?

Every patient presenting with an unexplained blackout should be given a 12-lead ECG (heart rhythm check)

It is important that the ECG is passed as normal.

Learn more about blackouts in more detail in this article

Treatments for blackouts

Treatment will often depend on the rhythm of the heart.

Slow heart rhythms causing blackouts will be treated with a device called a pacemaker. This is much more common in older people because the cause of the blackout is a slow heart rhythm caused by gradual wearing out of the hearts electrical system.

Fast heart rhythms that cause blackouts, may be dangerous/life threatening. Treatment can include:

  • Preventing the rhythm - with medication that slow or control the heart rhythm such as betablockers.
  • Treat the rhythm – for rhythms that are potentially life threatening it may also be prudent to give the patient the protection of an automatic implantable defibrillator. Alternatively, surgical procedures such as Atrial Fibrillation (AF) Ablation can be performed to treat rhythm problems such as Atrial Fibrillation if deemed appropriate.

Blackouts and Fainting Specialists

The consultants at OneWelbeck Heart Health have been assembled based on their hard-earned international reputations and expertise. Together, they cover the major London teaching hospitals and leading cardiac services, making up the largest independent cardiology group in the UK.