title: Evaluation of baroreflex sensitivity by the sequence method using blood pressure oscillations and R-R interval changes during deep respiration.
abstract: BACKGROUND
  Baroreflex sensitivity assessments have been considered to be important to evaluate cardiac autonomic neuropathy. The phenylephrine method, Valsalva maneuver or sequence method at rest caused several problems. We evaluated the usefulness of the sequence method during deep respiration.
  
  
  METHODS
  Baroreflex sensitivity was evaluated in 20 normal volunteers and 50 patients with Parkinson's disease. R-R intervals and systolic blood pressures were obtained by electrocardiogram and tonometry using a continuous blood pressure monitoring system. The sequence method is an evaluation of baroreflex sensitivity using sequences of 3 or more consecutive beats for 4 min. Baroreflex sensitivity was also assessed by the Valsalva maneuver at 5 beats before the peak systolic blood pressure of phase IV. The slope of the linear interrelationship between systolic blood pressure and the following R-R interval, i.e. baroreflex sensitivity (ms/mm Hg), was calculated with a correlation coefficient greater than 0.8.
  
  
  RESULTS
  The mean value of baroreflex sensitivity obtained by the Valsalva maneuver was 7.91 in normal volunteers and 5.35 in patients with Parkinson's disease; the one obtained by the sequence method at rest was 9.10 in normal volunteers and 8.42 in patients with Parkinson's disease, and the one obtained by the sequence method during deep respiration was 10.23 in normal volunteers and 6.73 in patients with Parkinson's disease. In some cases with Parkinson's disease, baroreflex sensitivities could not be found, whereas in all patients with Parkinson's disease, the sequence method during deep respiration could be used for evaluations. Significant correlations were found among the baroreflex sensitivities obtained by the Valsalva maneuver, and the sequence method at rest or during deep respiration in normal volunteers and patients with Parkinson's disease.
  
  
  CONCLUSIONS
  The baroreflex sensitivity obtained by the sequence method during deep respiration could be investigated noninvasively in all cases with PD, being thus a useful method for clinical evaluation of baroreflex sensitivity.
authors.affiliation: Department of Neurology, Aoto Hospital, Jikei University School of Medicine, Tokyo, Japan. h.oka@jikei.ac.jp
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Oka
authors.forename: Soichiro
authors.initials: S
authors.lastname: Mochio
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yoshioka
authors.forename: Masayo
authors.initials: M
authors.lastname: Morita
authors.forename: Kiyoharu
authors.initials: K
authors.lastname: Inoue
mesh_terms: D000368:Aged; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D016022:Case-Control Studies; D015259:Dopamine Agents / Q000627:therapeutic use; D004562:Electrocardiography / Q000379:methods; D006801:Humans; D007024:Hypotension, Orthostatic / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D016014:Linear Models; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D012119:Respiration; D012146:Rest / Q000502:physiology; D013997:Time Factors; D014636:Valsalva Maneuver / Q000502:physiology
chemical_list: D015259:Dopamine Agents