[Management of patients with syncope: from guidelines to clinical practice].

Syncope is defined as the transient loss of consciousness with spontaneous recovery, as a result of cerebral hypoperfusion. It is a very common clinical entity.1 Although it is difficult to establish the prevalence and incidence of syncopal episodes, recent data indicate that 9-35% of the Spanish population present some syncopal episode in their lifetime.2,3 There are a variety of causes which may trigger a syncopal episode.1 The most common is the neurally mediated response, in which a distinction should be made between vasovagal syncope, situational syncope, and syncope resulting from carotid sinus hypersensitivity. The second major cause is arrhythmia, whether this be bradyarrhythmia or tachyarrhythmia, which are common in patients with abnormal electrocardiograms (ECG) or different grades of structural heart disease. Syncope as a result of orthostatic hypotension is less common and is usually secondary to dysautonomia or the administration of drugs. Occasionally, syncope can be a clinical manifestation of different acute cardiopulmonary conditions, such as pulmonary embolism, myocardial infarction, or cardiac tamponade. On rare occasions it may be caused by subclavian steal syndrome. The severity and clinical impact of syncopal episodes are determined not only by their etiology, but also by other circumstances, such as how the episodes present themselves, the recurrence rate or the patient’s professional circumstances. Occasional syncopal episodes of a vasovagal etiology, with recognisable triggers and prodromes, therefore constitute a benign clinical episode Management of Patients With Syncope: From Guidelines to Clinical Practice