Syncope

Purpose

Syncope is a common clinical problem characterized by a transient, spontaneously self-terminating loss of consciousness with complete and prompt recovery, the cause of which is insufficiency of cerebral blood flow creating generalized anoxia, most commonly due to a transient fall of systemic arterial pressure to levels below those tolerated by the cerebrovascular autoregulation mechanism. A thorough evaluation of the underlying cause of syncope is warranted in all patients to precisely diagnose the underlying mechanism or cause in order to provide the appropriate treatment of syncope since it is challenging for many reasons. The purpose of this review on syncope is to provide a thorough differential diagnosis as to the underlying cardiac and non-cardiac causes with methods of assessment of the specific causes. Knowledge of the specific cause, especially in the setting of structural heart disease or primary electrical cardiac disease, has an increased incidence of sudden death and overall mortality. It is also important to establish whether or not syncope is due to orthostatic hypotension since it is associated with a twofold increased mortality, whereas those individuals with neurally mediated syncope have an excellent prognosis.