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Syncope: Temporary Loss of Consciousness or Fainting

The information below will help you understand why patients sometimes experience a temporary loss of consciousness or fainting, also known as syncope. The described symptoms do not necessarily mean that you have significant health problems, but if the symptoms persist and you feel concerned, please contact your physician. 

Woman leaning against a pole

What is Syncope

Syncope is the medical term for fainting or passing out. That means, you temporarily lose consciousness. The loss of consciousness happens suddenly, does not last long, and you recover from it quickly and fully. Syncope is fairly common and affects 3 to 4 percent of the population worldwide.

The Different Types of Syncope

As fainting is quite common it is usually not seen as something too serious. Unfortunately, fainting can be due to underlying health problems though. Let’s take a closer look at some of the different types of syncope. 

Reflex Syncope Cardiac Syncope Orthostatic Syncope Cerebrovascular Syncope
occurs when the body’s reflexes are not properly regulated which can lead to a sudden drop in blood pressure. This results in not enough blood getting to the brain—so you faint.   happens when your heart is unable to work as it should and cannot provide your brain with enough blood. This may be caused by various heart conditions.  occurs when the blood pressure drops when a person is standing up. This is due to gravity reducing the blood return to the heart. Usually, the brain overcomes this by stabilizing blood pressure. But in orthostatic syncope, brain coordination does not take place and you loose consciousness due to the sudden drop in blood pressure.  happens when diseases affect the blood vessels in and around the brain. The most common examples are stroke, carotid artery stenosis, brain aneurysms, and other vessel diseases of the brain. 


What Causes Syncope?

As explained in “The Different Types of Syncope”, there are various types and therefore various reasons why syncope can happen. These include: 

  • Sudden drop in blood pressure 
  • Standing for long hours 
  • Intense pain 
  • Extreme fear 
  • Feeling distressed 
  • Coughing, laughing or crying hard 
  • Pressure to the carotid sinus (this can be caused by wearing too tight collars or applying pressure to the neck) 
  • Dehydration 
  • Vomiting 
  • Diarrhea 
  • Blood loss 
  • Alcohol use 
  • Certain medications 
  • Parkinson’s disease 
  • Stroke 
  • Carotid artery stenosis 
  • Brain aneurysms 
  • Various vessel diseases of the brain

What are the Symptoms of Syncope?

Syncope can be associated with different symptoms that are experienced immediately before fainting: 

  • Feeling lightheaded 
  • Cool and clammy skin 
  • Feeling of weakness 
  • Unsteadiness 
  • Headache 
  • Nausea 
  • Seeing spots or blurred vision 
  • Ringing in the ears 
  • Blacking out 

Some people might also be confused immediately after regaining consciousness and will need a few minutes to completely recover.  

Man holding his head

How is Syncope Diagnosed?

If you only faint once and it was brought on by standing for a long time or being dehydrated, the cause is most likely harmless. Many people experience one or more episodes of syncope in their lives. However, without a medical check, you cannot know whether your fainting was harmless or a symptom of a serious health problem. To find the cause of syncope, your doctor will probably ask you questions about what you were doing shortly before fainting. In addition to a thorough physical examination, your doctor will most likely perform an electrocardiogram (ECG) while laying down and a stress test to take a closer look at your heart rhythm. Maybe they will also recommend a tilt table test (TTT). For this test, you will be attached to an ECG and blood pressure measuring machine to see if your heart rhythm or blood pressure changes when you change from lying to upright. But even with these tests, it will sometimes not be possible to find out what caused your fainting. In these cases, further examinations are required. 

Your doctor will most likely run some lab tests as well. Many doctors also prefer taking a closer look at your heart functions to understand the underlying reasons for the reoccurring syncope. The cause of a cardiac syncope, for instance, is not always visible with an electrocardiogram.  

Since cardiac arrhythmias may occur only temporarily it may be recommended to perform a long-term ECG. A Holter monitoring is a continuous 24-hour tape recording of an ECG. It is done with a portable device, which can be worn during daily activities. An external loop recorder (ELR) is fastened to the patient's belt and measures the ECG over several days. The data can be transmitted automatically to the physician or the patient can initiate data transfer. 

The implantation of a subcutaneous cardiac monitor or an insertable cardiac monitor (ICM) like the BIOMONITOR from BIOTRONIK is very useful to observe the heart rhythm over a longer period. This device may show the causes of previously inexplicable fainting episodes. 

In addition, an electrophysiological examination of the heart may be performed. This enables the physician with the help of special electrode catheters to analyze previously unclear cardiac arrhythmias in greater detail. If the cardiac arrhythmia does not occur by itself, the physician stimulates the heart with electrical impulses via the catheter to determine its type and origin. This invasive procedure is performed in an EP laboratory and monitored by X-ray. 


Man getting examined by physician

How is Syncope Treated?

Treatment for syncope depends on the underlying cause. If the reason for the fainting is a heart rhythm disorder, your doctor needs to determine which sort of disorder or arrhythmia is causing you to faint. Under “Related Topics” you will find links to various arrhythmias and how they are treated as well as tips on how to make lifestyle changes to live a heart-healthy life.



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