title: Cardiovascular autonomic control in patients undergoing left ventricular assist device (LVAD) support and pharmacologic therapy.
abstract: OBJECTIVE
  The objective of the study is to determine cardiac autonomic control in patients undergoing assessment for and/or LVAD therapy.
  
  
  METHODS
  Heart rate variability (HRV) was measured in 17 explanted LVAD, 17 implanted LVAD and 23 NYHA III-IV classified chronic heart failure (CHF) patients and ten healthy matched controls under three conditions: supine free breathing, standing and supine controlled breathing. Five measures of HRV were assessed: mean R-R interval (mR-R), high frequency (HF) and low frequency (LF) spectral power, LF in normalised units (LFnu), and LF to HF (LF:HF) ratio.
  
  
  RESULTS
  Repeat measures ANOVA showed significant (p < 0.05) differences in HRV between all three conditions within groups. Lower values were observed in CHF for LF(in log natural units) compared with explanted patients (-1.4 [95% CI -2.6 to -0.7], p = 0.04) and controls (-2.1 [-3.5 to -0.7], p = 0.001) and for LF:HF compared with implanted patients under paced breathing conditions (z = -2.7, p = 0.007) and controls in standing (z = -2.9, p = 0.004) and paced breathing conditions (z = -2.3, p = 0.02). However, no significant differences were seen between explanted, implanted and control groups under any condition.
  
  
  CONCLUSIONS
  Patients implanted with an LVAD and explanted from a LVAD following myocardial recovery demonstrate a more normal dynamic response to autonomic stimuli and have a lower HRV risk profile compared to CHF patients.
authors.affiliation: Department of Primary Care Health Sciences, University of Oxford, Oxford, UK. Electronic address: david.nunan@phc.ox.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Nunan
authors.forename: Gavin R H
authors.initials: GR
authors.lastname: Sandercock
authors.forename: Robert S
authors.initials: RS
authors.lastname: George
authors.forename: Djordje G
authors.initials: DG
authors.lastname: Jakovljevic
authors.forename: Gay
authors.initials: G
authors.lastname: Donovan
authors.forename: Robert
authors.initials: R
authors.lastname: Bougard
authors.forename: Magdi H
authors.initials: MH
authors.lastname: Yacoub
authors.forename: David A
authors.initials: DA
authors.lastname: Brodie
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Birks
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000187:drug effects / Q000502:physiology*; D002317:Cardiovascular Agents / Q000494:pharmacology / Q000627:therapeutic use; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology / Q000601:surgery*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006353:Heart-Assist Devices / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D002317:Cardiovascular Agents
keywords: Bridge-to-recovery; Heart rate variability; Normalisation; Prognosis; Reverse remodelling