Carotid Sinus Hypersensitivity - PubMed

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan.

2022 Oct 17.

Carotid sinus hypersensitivity (CSH) is a condition that commonly manifests as syncope. Hypersensitive receptors in the carotid sinus cause an exaggerated response when stimulated, leading to CSH. The place where the internal and external carotid arteries meet to make the common carotid artery is called the carotid sinus (dilated area in the carotid bifurcation); this is a kind of neurovascular structure, which contains baroreceptors ("baro" is the Greek word for pressure or stretch) (see Graphic. Pathophysiology of Carotid Hypersensitivity Syndrome).

The baroreceptors at the carotid sinus shoot neural signals through the glossopharyngeal nerve to the solitary nucleus in the medulla. Increased pressure or stretch sensed via baroreceptors activates the parasympathetic nervous system, with the net effect of vasodilation, bradycardia, and hypotension. Hypotension further eliminates the inhibitory effect of baroreceptors.

However, the objective definition of CSH includes the evolution of 3 seconds or more of cardiac pause "asystole" (cardioinhibitory) or a decrease in the systolic blood pressure 50 mmHg "hypotension" or more (vasopressor) if the massage results in hypotension and bradycardia then it is called mixed (cardioinhibitory and vasopressor), while a carotid sinus massage is made regardless of symptoms occurrence (ie, might fulfill the criteria but be asymptomatic).

There are three subtypes of CSH: cardioinhibitory, vasodepressor, and a mixed type (cardioinhibitory and vasopressor) (see Graphic. The Three Types of Carotid Sinus Hypersensitivity).

Disclosure: Antoine Kharsa declares no relevant financial relationships with ineligible companies.

Disclosure: Roopma Wadhwa declares no relevant financial relationships with ineligible companies.

1. 1. Wu TC. What is the Real Clinical Significance of Carotid Sinus Hypersensitivity in Clinical Practice? A Dilemma Still Waiting for Answers. Arq Bras Cardiol. 2020 Feb;114(2):254-255. - PMC - PubMed
2. 1. Zhang S, Wei C, Zhang M, Su M, He S, He Y. Syncope and hypotension associated with carotid sinus hypersensitivity in a patient with nasopharyngeal carcinoma: A case report. Medicine (Baltimore) 2018 Sep;97(37):e12335. - PMC - PubMed
3. 1. Andani R, Khan YS. StatPearls [Internet] StatPearls Publishing; Treasure Island (FL): 2023. Jul 24, Anatomy, Head and Neck: Carotid Sinus. - PubMed
4. 1. Miller VM, Kenny RA, Slade JY, Oakley AE, Kalaria RN. Medullary autonomic pathology in carotid sinus hypersensitivity. Neuropathol Appl Neurobiol. 2008 Aug;34(4):403-11. - PubMed
5. 1. da Silva RM. Syncope: epidemiology, etiology, and prognosis. Front Physiol. 2014;5:471. - PMC - PubMed