[Observation and provocation in diagnostics of syncope].

Despite a large number of modern examination techniques, possibilities for differential diagnostics of syncope remain limited even at the beginning of the 21st century. Up to 35% of patients get discharged from hospitals without knowing the exact nature of loss of consciousness. The main reason for this is that a syncopal attack is a symptom of a range of diseases and conditions, and a large number of examination methods may be necessary to establish its cause. One group of methods helps find the supposed morphological substrate of attacks, while other methods serve as evidence of its pathogenetic mechanism. What is their real diagnostic value? And which strategy--waiting for a spontaneous attack and observing it or provocation of syncope--is the best one when a patient with syncope is being examined? The article discusses advantages and disadvantages of diagnostic methods that are commonly used in diagnostics of reasons for loss of consciousness.