[From loss of consciousness to syncope].

Syncope is the most frequent cause for transient loss of consciousness. Recent ESC guidelines pinpoint the position of syncope within the context of loss of consciousness. The individual risk of syncope is determined by various factors. Odds are that almost one in two women and one in four men suffers from syncope at least once in their lives. Age-dependent risk is highest at both the age of 15 and after the 60(th) birthday. Only a fraction of cases are witnessed by a doctor, which makes it difficult to analyze. Prognosis after syncope is strictly related to the existence of structural heart disease. Therefore, its diagnosis and therapy should be given priority. In case of high risk of recurrence, syncope should be adequately treated to prevent further relapse, regardless of the primary disease. Syncopes are classified on the basis of their pathophysiological cause: reflex syncope, orthostatic syncope, arrhythmic cardiac syncope, mechanically caused syncope due to structural cardiovascular disease, and syncope due to cerebrovascular disease. The cause of up to one third of syncopes remains unknown; however, the majority of which are probably reflex syncopes.