Cardiologist, Electrophysiologist

Fainting: When Should I be Worried?

Fainting (Syncope): When Should I be Worried?

Fainting (or syncope) can be a scary experience for everyone involved. One moment the person is conscious and the next, they are flat on their back. This sudden loss of consciousness may be due to a drop in blood pressure, and while the situation can be visually shocking, the experience is rather common. It is estimated that 3-5% of all emergency department admissions in Australia are related to such episodes.

For most people, fainting occurs once in a great while; triggered by things like, the sight of blood, or experiencing extreme emotional distress. However, in some cases, syncopal episodes are the result of serious medical conditions. These may include hormonal changes, neurological conditions and significant cardiac events, such as potentially lethal arrhythmias.

As a consequence of a sudden fainting episode, it is common for people to sustain limb and facial injuries from falling, which in itself can be very dangerous. However, syncope may be a symptom of a more sinister underlying problem, so understanding when you need to see a doctor may be vital in preventing further injuries.


There are many common causes of fainting. These include;

  • Cardiac conditions – slow heart rates (bradycardia), rapid heart rate (tachycardia)
  • Psychiatric causes – fright, panic or hysteria (types of emotional distress)
  • Structural heart diseases – aortic stenosis or hypertrophic obstructive cardiomyopathy
  • Metabolic issues – low blood pressure, hyperventilation, hypoglycaemia
  • Neurological issues – epilepsy, transient ischaemic attacks (mini-stroke)

Those that frequently experience syncope episodes may “feel” when an event is about to occur. This feeling is referred to as “prodrome”, which can include symptoms of nausea, sweating and loss of colour.

Dr Vincent Deen, Brisbane Cardiologist and Electrophysiologist said, “Syncope has significant impacts on a patient’s quality of life. They live with uncertainty and anxiety because they have no control over the events.”

While some syncope events can be classified as “one-off” episodes, identifying the “red flags” associated with fainting can act as early warning signs to more serious, undiagnosed conditions.

“It is important that doctors evaluate patients properly, and institute therapy quickly.”

Cardiac related syncope episodes are especially dangerous. Gold Coast Cardiologist and Electrophysiologist, Dr John Meulet explains syncope episodes related to structural and valvular heart disease, have a 30% adverse outcome within twelve months if left untreated.

“If a patient has an episode of syncope with physical exertion, that is always abnormal and they should be referred for exclusion of an underlying cardiovascular cause,” Dr Meulet said.


Red flags of fainting can include but are not limited to;

  • Slow heart rate (less than 60bpm)
  • Cardiac murmurs
  • Fainting whilst exercising
  • Fainting whilst at rest (in bed or seated)
  • Family history of heart conditions

Patient diagnosis can involve a number of routine tests, such as blood tests, electrocardiograph (ECG), echocardiograms and external heart monitors. The tests rely on how often the episodes of syncope occur and range from 24hr Holter monitoring to 3 years implanted loop recording.

“The best test to try and find the cause of syncope starts with basic history and physical examination. This can reveal the cause in about 50% of cases. From there we can do some bedside investigation such as Holter monitoring and external loop monitoring, ” Dr Vince Deen said.

While these tests are common practice in diagnosing cardiac related syncope, the frequency of the episodes may make diagnosis difficult as many patients experience syncope events infrequently.

As a result, the quality of life for those patients with syncope but no formal diagnosis can dwindle over time, as patients become anxious and dependent on others to help with everyday tasks, in fear of sudden episodes.

Fainting can be a serious issue and should never be ignored. If in doubt, see your local doctor for an assessment and discussion.


Written by Bella Schwarzenecker

and edited by Shane Bassett, Clinical Content Director, Connect The Docs, RN/BN/CCRN

Image Credit: Sarvodaya Healthcare



All information contained in this article has been derived from Hope For Hearts, cardiac resource centre.

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