title: Comparison of 24-hour cardiovascular and autonomic function in paraplegia, tetraplegia, and control groups: implications for cardiovascular risk.
abstract: BACKGROUND
  Fluctuations in 24-hour cardiovascular hemodynamics, specifically heart rate (HR) and blood pressure (BP), are thought to reflect autonomic nervous system (ANS) activity. Persons with spinal cord injury (SCI) represent a model of ANS dysfunction, which may affect 24-hour hemodynamics and predispose these individuals to increased cardiovascular disease risk.
  
  
  OBJECTIVE
  To determine 24-hour cardiovascular and ANS function among individuals with tetraplegia (n=20; TETRA: C4-C8), high paraplegia (n=10; HP: T2-T5), low paraplegia (n=9; LP: T7-T12), and non-SCI controls (n=10). Twenty-four-hour ANS function was assessed by time domain parameters of heart rate variability (HRV); the standard deviation of the 5-minute average R-R intervals (SDANN; milliseconds/ms), and the root-mean square of the standard deviation of the R-R intervals (rMSSD; ms). Subjects wore 24-hour ambulatory monitors to record HR, HRV, and BP. Mixed analysis of variance (ANOVA) revealed significantly lower 24-hour BP in the tetraplegic group; however, BP did not differ between the HP, LP, and control groups. Mixed ANOVA suggested significantly elevated 24-hour HR in the HP and LP groups compared to the TETRA and control groups (P<0.05); daytime HR was higher in both paraplegic groups compared to the TETRA and control groups (P<0.01) and nighttime HR was significantly elevated in the LP group compared to the TETRA and control groups (P<0.01). Twenty-four-hour SDANN was significantly increased in the HP group compared to the LP and TETRA groups (P<0.05) and rMSSD was significantly lower in the LP compared to the other three groups (P<0.05). Elevated 24-hour HR in persons with paraplegia, in concert with altered HRV dynamics, may impart significant adverse cardiovascular consequences, which are currently unappreciated.
authors: James J. Peters VAMC, Bronx, NY, Center of Excellence, USA.
authors: Dwindally
authors: D
authors: Rosado-Rivera
authors: M
authors: M
authors: Radulovic
authors: John P
authors: JP
authors: Handrakis
authors: Christopher M
authors: CM
authors: Cirnigliaro
authors: A Marley
authors: AM
authors: Jensen
authors: Steve
authors: S
authors: Kirshblum
authors: William A
authors: WA
authors: Bauman
authors: Jill Maria
authors: JM
authors: Wecht
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001342:Autonomic Nervous System Diseases / Q000209:etiology*; D001794:Blood Pressure / Q000502:physiology; D002318:Cardiovascular Diseases / Q000209:etiology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010264:Paraplegia / Q000150:complications*; D011782:Quadriplegia / Q000150:complications*; D013997:Time Factors