Syncope is the temporary loss of consciousness due to a sudden decline in blood flow to the brain. It may be caused by an irregular cardiac rate or rhythm or by changes of blood volume or distribution. Syncope can occur in otherwise healthy people. The patient feels faint, dizzy, or lightheaded (presyncope), or loses consciousness (syncope).

Non-cardiac syncope is treated acutely by lying down with the legs elevated. Infrequent episodes of non-cardiac syncope usually do not require treatment.

Syncope is a dramatic event and can even be life-threatening if not treated appropriately. Generally, however, recovery is usually complete within minutes to hours.

Prepared by the National Institutes of Health