Baroreceptor sensitivity response to phase IV of the Valsalva maneuver in spinal cord injury

Due to the increased prevalence of ischemic heart disease and hypertension reported in individuals with chronic spinal cord injury (SCI), we investigated whether subjects with low level SCI (paraplegia), without apparent evidence of coronary artery disease, exhibit normal baroreceptor and autonomic...

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Bibliographic Details
Published in:Clinical autonomic research 1998-04, Vol.8 (2), p.111-118
Main Authors: Grimm, D R, Almenoff, P L, Bauman, W A, De Meersman, R E
Format: Article
Language:English
Subjects:
Adult
Humans
Hypertension - complications
Hypertension - physiopathology
Male
Middle Aged
Paraplegia - complications
Paraplegia - physiopathology
Pressoreceptors - physiopathology
Reference Values
Sinus of Valsalva - physiopathology
Spinal Cord Injuries - complications
Spinal Cord Injuries - physiopathology
Valsalva Maneuver
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Summary:Due to the increased prevalence of ischemic heart disease and hypertension reported in individuals with chronic spinal cord injury (SCI), we investigated whether subjects with low level SCI (paraplegia), without apparent evidence of coronary artery disease, exhibit normal baroreceptor and autonomic function. Eighteen males participated in this study: seven normotensive with paraplegia, five hypertensive with paraplegia and six normotensive non-SCI controls. The Valsalva maneuver was performed by maintaining a pressure of 40 mmHg over 15 s and R-R intervals (RRI) and arterial blood pressure were measured continuously. Phase IV of the Valsalva maneuver was determined by linear regression analysis between RRI and systolic pressure, with a final slope calculated. The power spectra for RRI and blood pressure variability parameters were also analyzed, in addition to the index alpha, a frequency domain estimate of the overall gain in baroreceptor control of the RRI-arterial blood pressure. The normotensive subjects with paraplegia were found to have an impaired baroreceptor response when compared with age-matched, non-SCI controls. In addition, the levels of both the low frequency and high frequency spectral components of RRI and the index alpha were reduced in these individuals at rest. These cumulative findings strongly suggest that the integrity of the sinoaortic baroreceptors, as well as efferent parasympathetic function, may be compromised in otherwise apparently healthy individuals with chronic paraplegia.
ISSN:0959-9851
1619-1560
DOI:10.1007/bf02267821