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Clinical Autonomic Research

, Volume 11, Issue 2, pp 109–113 | Cite as

Carotid sinus “irritability” rather than hypersensitivity: a new name for an old syndrome?

  • Christopher R. Cole
  • Julie Zuckerman
  • Benjamin D. Levine
Research Article

Abstract

Carotid sinus hypersensitivity (CSH) is a well-described cause of syncope, resulting in bradycardia and/or hypotension in response to neck pressure. The authors hypothesized that (CSH) represents an inappropriate response of the baroreflex system to a nonphysiologic stimulus, rather than a truly hypersensitive carotid carotid sinus (ie, excessive vagotonia and sympathoinhibition in response to arterial hypertension). To test their hypothesis, the authors used a neck chamber to deliver stepped, R-wave-triggered changes in transmural carotid sinus pressure, from +40 to −60 mm Hg, during a single held expiration. The authors studied 7 men (age 69±8y; mean age ±SD) with carotid sinus syndrome and 10 age- and sex-matched controls. Seven repetitions of pressure changes were averaged, and the carotid sinus response described by changes in the R-R interval. There was no statistical difference in carotid-cardiac baroreflex gain (R-R interval/pressure change; mean gain ±SD, 3.0±2.1 msec/mm Hg and 2.2±3.0 msec/mm Hg, respectively) or other markers of carotid baroreflex responses between the subjects and controls. These preliminary results suggest that (CSH) may not be a “hypersensitive” reflex, but rather an inappropriate response, or “irritability,” of the baroreflex system to nonphysiologic deformation of the carotid sinus and/or surrounding tissues.

Key words

syncope carotid arteries baroreceptors 

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Copyright information

© Lippincott Williams & Wilkins 2001

Authors and Affiliations

  • Christopher R. Cole
    • 1
    • 2
  • Julie Zuckerman
    • 1
  • Benjamin D. Levine
    • 1
    • 2
  1. 1.The Institute of Exercise and Environmental MedicinePresbyterian Hospital of DallasDallasUSA
  2. 2.Division of Cardiology, Dept. of Internal MedicineUniversity of Texas Southwestern Medical Center at DallasDallasUSA

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