What is Syncope?
Syncope is the medical term for fainting or passing out. It is a temporary loss of consciousness characterised by rapid onset, short duration, and spontaneous recovery. Usually, an abrupt lack of blood supply to the brain leads to fainting. Syncope can either occur suddenly without any warning symptoms or can be preceded by sweating, nausea, blurred vision, pale skin and light-headedness.
There is a wide range of causes for syncope. Fainting may be caused by emotional stress, intense pain, sudden changes in body position, medication, overheating, dehydration, exhaustion, pressure to the carotid sinus in the neck, or even heavy coughing. It may also be the result of diseases of the heart or the lungs or neurologic, psychiatric and/or metabolic disorders.
The most serious causes for syncope are heart-related because they may lead to acute life threatening events. These include heart arrhythmias, diseases of the heart valves or the heart muscle as well as coronary artery disease (CAD) .
As there are so many possible causes for fainting and these causes may be transient, a physician will not always be able to identify the cause of a single syncope. If you have experienced only one syncope accompanied by some of the warning signs mentioned above and recovered completely afterwards, it was most likely harmless. In fact, 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 be safe, a physician should examine you after you have experienced syncope.
In order to detect the cause of syncope, a physician asks you specific questions about the events preceding the syncope and your medical history. After a thorough physical examination, he performs an electrocardiogram (ECG or EKG) while resting and a stress test to measure the heart rhythm. A tilt table test (TTT) enables physicians to monitor a patient’s ECG and blood pressure as they change from lying to an upright position. Sometimes these tests determine neither the cause of your fainting nor will they be able to exclude underlying cardiac arrhythmias. In these cases, further examinations are required.
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 implant of a subcutaneous cardiac monitor or an insertable cardiac monitor (ICM) is very useful to observe the ECG over a longer period (over years, if necessary) and to detect arrhythmias. This device may show the causes of previously inexplicable syncope episodes.
An electrophysiological examination of the heart enables the physician with the help of special electrode catheters to analyse previously unclear cardiac arrhythmia in greater detail and to determine its origin. If the cardiac arrhythmia does not occur by itself, the physician stimulates the heart with electrical impulses via the catheter in order to determine its type and origin. This invasive procedure is performed in an EP laboratory and monitored by X-ray.
In addition, other potential causes of fainting must be considered, e.g., seizure, stroke, concussion, low blood oxygen level, low blood sugar, intoxication and some psychiatric disorders. Treatment for syncope depends on the underlying cause. To learn more about the treatment of heart rhythm disorders, please click here .