title: Autonomic dysfunction in reversible cerebral vasoconstriction syndromes.
abstract: BACKGROUND
  Autonomic imbalance may play an important role in the pathogenesis of reversible cerebral vasoconstriction syndromes (RCVS). This study aimed to assess the autonomic function by analyzing heart rate variability (HRV) in patients with RCVS.
  
  
  METHODS
  Patients with RCVS and age- and gender-matched controls were consecutively recruited. All patients (both ictal and remission stage) and controls underwent 24-hour ambulatory electrocardiographic (ECG) recordings. HRV measures covering time and frequency domains were used to assess autonomic functioning.
  
  
  RESULTS
  Thirty-nine patients with RCVS and 39 controls completed the study. Compared to the controls, RCVS patients during the ictal stage showed reductions in parasympathetic-related indices, including the root mean square of difference of consecutive interbeat intervals (RMSSD) (22.1 ± 7.0 vs. 35.2 ± 14.2, p < 0.001), the percentage of adjacent intervals that varied by more than 50 ms (pNN50) (3.7 ± 3.4 vs. 10.6 ± 8.1, p < 0.001), and high-frequency power (HF) (5.82 ± 0.73 vs. 6.77 ± 0.74; p < 0.001), and increased low-frequency/high-frequency (LF/HF) ratio (index of sympathovagal balance) (3.38 ± 1.32 vs. 2.48 ± 1.07; p =0.001). These HRV indices improved partially but remained significantly different from controls during remission.
  
  
  CONCLUSIONS
  Decreased parasympathetic modulations and accentuated sympathetic activity might be a biological trait in patients with RCVS.
authors.affiliation: Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan. sjwang@vghtpe.gov.tw.
authors.forename: Shih-Pin
authors.initials: SP
authors.lastname: Chen
authors.forename: Albert C
authors.initials: AC
authors.lastname: Yang
authors.forename: Jong-Ling
authors.initials: JL
authors.lastname: Fuh
authors.forename: Shuu-Jiun
authors.initials: SJ
authors.lastname: Wang
mesh_terms: D001342:Autonomic Nervous System Diseases / Q000150:complications*; D001921:Brain / Q000098:blood supply*; D002561:Cerebrovascular Disorders / Q000150:complications / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D051270:Headache Disorders, Primary / Q000150:complications* / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014661:Vasoconstriction / Q000502:physiology*