Syncope is a common phenomenon, well-known to all pediatricians: it is defined as a sudden transient loss of consciousness associated with inability to maintain postural tone that is incompatible with a seizure disorder, vertigo, dizziness, coma, shock or other states of altered consciousness. The purpose of this study are to analyse the multiple causes of syncope, to determine the characteristics of pediatric patients with syncope, to define the pathophysiologic mechanisms that result in neurally mediated syncope.