Neurocardiogenic Syncope and Rlated Syndromes of Orthostatic Intolerance

The medical term “syncope” is derived from the Greek word “synkoptein,” meaning “to cut short” and refers to the transient loss of consciousness and postural tone with spontaneous recovery. Recurrent syncope is perhaps one of the most challenging and, at the same time, most frustrating problems that is encountered in clinical practice. The large and varied number of possible causes can make the evaluation of patients with recurrent syncope a particularly daunting endeavor. Over the last decade, it has become clear that transient alterations in autonomic nervous system tone leading to hypotension and bradycardia are important causes of syncope. Rather than a single entity, these autonomic disturbances represent a heterogeneous group of disorders that, although sharing certain characteristics, are nonetheless distinct entities. This brief review will attempt to provide some basic background material on syncope, review some aspects of pathophysiology of neurocardiogenic syncope, and present current concepts in the diagnosis and management of these autonomically mediated disorders of orthostatic tolerance.