Cerebral autoregulation is impaired in cardioinhibitory carotid sinus syndrome

Parry, Steve W.; Steen, Nick; Baptist, M; Fiaschi, Kathia; Parry, O.; Kenny, Rose Anne

doi:10.1136/hrt.2004.053348

Cited by 30 publications

(17 citation statements)

References 29 publications

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“…In four patients with Shy-Drager syndrome, Briebach et al [15] suggested that CA was preserved in at least three of the individuals studied. In secondary causes of syncope, CA was deemed to be impaired in patients with diabetes [24,57,83,123,159] as well as in carotid sinus syndrome [72,113].…”

Section: Ca In Syncope and Ans Conditionsmentioning

confidence: 99%

Transcranial Doppler for evaluation of cerebral autoregulation

2009

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Transcranial Doppler ultrasound (TCD) can measure cerebral blood flow velocity in the main intracranial vessels non-invasively and with high accuracy. Combined with the availability of non-invasive devices for continuous measurement of arterial blood pressure, the relatively low cost, ease-of-use, and excellent temporal resolution of TCD have stimulated the development of new techniques to assess cerebral autoregulation in the laboratory or bedside using a dynamic approach, instead of the more classical 'static' method. Clinical applications have shown consistent results in certain conditions such as severe head injury and carotid artery disease. Studies in syncopal patients revealed a more complex pattern due to aetiological non-homogeneity and methodological limitations mainly due to inadequate sample-size. Different analytical models to quantify autoregulatory performance have also contributed to the diversity of results in the literature. The review concludes with specific recommendations for areas where further validation and research are needed to improve the reliability and usefulness of TCD in clinical practice.

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Section: Ca In Syncope and Ans Conditionsmentioning

confidence: 99%

Transcranial Doppler for evaluation of cerebral autoregulation

2009

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“…They had, however, documented large increases in cerebrovascular resistance following CSM with no pacing (OOO), but attributed this to the CPP dropping below the lower limit of autoregulation . A subsequent study by our group suggested that cerebral autoregulation is impaired in symptomatic CSH through the observation of an overall reduction in cerebral blood flow velocity and increase in cerebrovascular resistance in subjects with symptomatic CSH compared with healthy older controls whose CSH status was unknown. These previous studies had not considered individuals with asymptomatic CSH.…”

Section: Discussionmentioning

confidence: 92%

Symptomatic Presentation of Carotid Sinus Hypersensitivity Is Associated With Impaired Cerebral Autoregulation

Tan

Chadwick

Kerr

et al. 2014

JAHA

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BackgroundCarotid sinus hypersensitivity (CSH) is associated with syncope, unexplained falls, and drop attacks in older people but occurs asymptomatically in 35% of community‐dwelling elders. We hypothesized that impaired cerebral autoregulation is associated with the conversion of asymptomatic CSH to symptomatic CSH. We therefore conducted a case–control study evaluating individuals with CSH with and without the symptoms of syncope or unexplained falls, as well as non‐CSH controls, to determine whether the blood pressure and heart rate changes associated with CSH are associated with symptoms only when cerebral autoregulation is altered.Methods and ResultsBilateral middle cerebral artery blood flow velocities (BFV) were measured in consecutive patients with symptomatic CSH (n=22) and asymptomatic controls with (n=18) and without CSH (n=14) using transcranial Doppler ultrasonography during lower body negative pressure‐induced systemic hypotension. Within‐group comparisons revealed significantly lower cerebrovascular resistance index (CVRi) at nadir for the asymptomatic CSH group (right, mean [95% CI]: 2.2 [1.8, 2.8] versus 2.6 [2.2, 3.0]; P=0.005; left: 2.8 [2.4, 3.3] versus 3.1 [2.7, 3.8]; P=0.016). Between‐group comparisons showed higher mean BFV (right: estimated mean difference, B=5.49 [1.98, 8.80], P=0.003; left: 4.82 [1.52, 8.11], P=0.005) and lower CVRi (right: B=0.08 [0.03, 0.12], P=0.003, left: B=0.07 [0.02, 0.12], P=0.006) in asymptomatic CSH versus symptomatic CSH groups. There were no significant differences in bilateral mean BFV or right CVRi between the non‐CSH and symptomatic CSH groups but differences were present for left CVRi (B=0.07 [0.02, 0.013], P=0.015).ConclusionCerebral autoregulation is altered in symptomatic CSH and therefore appears to be associated with the development of hypotension‐related symptoms in individuals with CSH.

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“…Age and baseline blood pressure has only a minor effect on the lower limit of blood pressure necessary to maintain consciousness. 32 Cerebral autoregulation is also impaired in CSS, with alterations in cerebral blood flow velocities detected by transcranial Doppler during lower body negative pressureinduced hypotension 33 and CSM 34 in patients with CSS versus control individuals. However, the pathophysiologic and potential therapeutic implications of this finding have yet to be elucidated.…”

Section: Neurally Mediated Syncopementioning

confidence: 99%