title: External Counterpulsation Increases Beat-to-Beat Heart Rate Variability in Patients with Ischemic Stroke.
abstract: OBJECTIVE
  External counterpulsation (ECP) is a noninvasive method used to augment cerebral perfusion in ischemic stroke. However, the response of beat-to-beat heart rate variability (HRV) in patients with ischemic stroke during ECP remains unknown.
  
  
  METHODS
  Forty-eight patients with unilateral ischemic stroke at the subacute stage and 14 healthy controls were recruited. Beat-to-beat heart rate before, during, and after ECP was monitored. The frequency components of HRV were calculated using power spectral analysis. Very low frequency (VLF; <.04 Hz), low frequency (LF; .04-.15 Hz), high frequency (HF; .15-.40 Hz), total power spectral density (TP; <.40 Hz), and LF/HF ratio were calculated.
  
  
  RESULTS
  In stroke patients, although there were no statistical differences in all of the HRV components, the HRV at VLF showed a trend of increase during ECP compared with baseline in the left-sided stroke patients (P = .083). After ECP, the HRV at LF and TP remained higher than baseline in the right-sided stroke patients (LF, 209.4 versus 117.9, P = .050; TP, 1275.6 versus 390.2, P = .017, respectively). Besides, the HRV at TP also increased after ECP compared with baseline in the left-sided stroke patients (563.0 versus 298.3, P = .029).
  
  
  CONCLUSIONS
  Irrespective of the side of the ischemia, patients showed an increased beat-to-beat HRV after ECP. Additionally, sympathetic and parasympathetic cardiac modulations were increased after ECP in patients after right-sided subacute stroke.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xiong
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Ge
authors.initials: G
authors.lastname: Tian
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Lin
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Xiangyan
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Thomas Wai Hong
authors.initials: TWH
authors.lastname: Leung
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Yannie Oi Yan
authors.initials: YOY
authors.lastname: Soo
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China. Electronic address: ks-wong@cuhk.edu.hk.
authors.forename: Lawrence Ka Sing
authors.initials: LKS
authors.lastname: Wong
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D002560:Cerebrovascular Circulation; D015908:Counterpulsation / Q000009:adverse effects; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D020521:Stroke / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D013564:Sympathetic Nervous System / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome
keywords: External counterpulsation; heart rate variability; infarct location; ischemic stroke