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Carotid sinus hypersensitivity

Brian Olshansky, MD
Section Editor
Leonard I Ganz, MD, FHRS, FACC
Deputy Editor
Brian C Downey, MD, FACC


Hypersensitivity of the afferent or efferent limbs of the carotid sinus reflex arc results in vagal activation and/or sympathetic inhibition, which leads to bradycardia and/or vasodilation; this is also called the carotid sinus syndrome or carotid sinus syncope.

Carotid sinus syncope is similar to vasovagal (neurocardiogenic) syncope since both are forms of reflex syncope reflecting alterations in autonomic tone with similar clinical manifestations. However, precipitating factors for these two types of syncope differ and carotid sinus hypersensitivity tends to occur in older patients. (See 'Prevalence and clinical features' below.)

Carotid sinus hypersensitivity will be reviewed here. Other types of reflex syncope including vasovagal syncope and general discussions of the pathogenesis, etiology, and evaluation of syncope are discussed separately. (See "Reflex syncope in adults: Clinical presentation and diagnostic evaluation" and "Syncope in adults: Epidemiology, pathogenesis, and etiologies" and "Syncope in adults: Clinical manifestations and diagnostic evaluation" and "Overview of craniofacial pain", section on 'Glossopharyngeal neuralgia'.)


The frequency of carotid sinus hypersensitivity in patients with syncope depends upon how it is defined [1]:

"Spontaneous carotid sinus syndrome" is diagnosed when by history spontaneous syncope occurs after accidental mechanical manipulation (eg, pressure from shaving or tight collars) of the carotid sinuses. Syncope can often be reproduced by carotid sinus massage. This clinical syndrome is rare, accounting for about 1 percent of syncope cases [2].

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Literature review current through: Sep 2017. | This topic last updated: Aug 28, 2017.
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