title: Non-invasive measurement of baroreflex during Valsalva maneuver: Evaluation of alpha and beta-adrenergic components.
abstract: OBJECTIVE
  To evaluate alpha and beta components of adrenergic baroreflex sensitivity (BRSa) in Valsalva maneuver (VM).
  
  
  METHODS
  BRSa was studied in 89 healthy subjects aged 30±13 [16-75] years. Subjects were divided into three groups per blood pressure (BP) patterns associated with relatively balanced or increased alpha-adrenergic modulation: (1) BAR (n=43) - Balanced Autonomic Response with a BP dip below baseline in late phase II (IIL) and recovery in phase IV; (2) SAR (n=16) - Suppressed Autonomic Response with a non-dipping BP; and (3) AAR (n=30) - Augmented Autonomic Response with a BP recovery in phase IIL. Discrete (alpha and beta) BRSa formulae were produced using alpha- or beta-adrenergic phases: α-BRSa (phase IIL) and β-BRSa (phase IV), respectively. Discrete BRSa were studied to determine potential correlations to BRSa1 (validated BRSa evaluation) and evaluated for reliability.
  
  
  RESULTS
  Patterns with higher α-adrenergic influence showed correlation between α-BRSa and BRSa1 (AAR: r=0.447, p<0.05; SAR: r=0.774, p<0.01). BAR showed correlation between β-BRSa and BRSa1 (r=-0.566, p<0.01), and α- and β-adrenergic coefficients (r=-0.381, p<0.05). Discrete BRSa were more reliable than BRSa1 (n=33; p<0.05).
  
  
  CONCLUSIONS
  Discrete BRSa are reproducible and correlated with BRSa1.
  
  
  CONCLUSIONS
  If validated, discrete BRSa may differentiate physiologic variances and vague dysautonomia.
authors.affiliation: Department of Clinical Neurological Sciences, University Hospital, London Health Sciences Centre, London, Ontario, Canada; Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
authors.forename: Iryna S
authors.initials: IS
authors.lastname: Palamarchuk
authors.affiliation: Department of Clinical Neurological Sciences, University Hospital, London Health Sciences Centre, London, Ontario, Canada.
authors.forename: Jacquie
authors.initials: J
authors.lastname: Baker
authors.affiliation: Department of Clinical Neurological Sciences, University Hospital, London Health Sciences Centre, London, Ontario, Canada; Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada. Electronic address: kkimpin@uwo.ca.
authors.forename: Kurt
authors.initials: K
authors.lastname: Kimpinski
mesh_terms: D000293:Adolescent; D059331:Adrenergic Neurons / Q000502:physiology*; D000328:Adult; D000368:Aged; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014636:Valsalva Maneuver / Q000502:physiology*; D055815:Young Adult
keywords: Adrenergic baroreflex; Alpha and beta-adrenergic indices; Hemodynamic patterns; Valsalva maneuver