title: Adaptive servo-ventilation therapy improves cardiac sympathetic nerve activity in patients with heart failure.
abstract: OBJECTIVE
  This study investigated whether abnormal cardiac sympathetic nerve activity (SNA) is associated with the severity of central sleep apnoea (CSA) and whether adaptive servo-ventilation (ASV) therapy can improve cardiac SNA in heart failure (HF) patients with predominant CSA.
  
  
  RESULTS
  Overnight polysomnography was conducted to diagnose CSA. Cardiac SNA was analysed by [123I]metaiodobenzylguanidine scintigraphy in 26 consecutive HF patients with predominant CSA. Of the 26 patients, 10 agreed to ASV therapy. Cardiac SNA was analysed 6 months after initiating ASV based on a non-randomized protocol. The apnoea-hypopnoea index and central apnoea index were significantly correlated with the washout rate (WR) and a delayed heart to mediastinal (H/M) ratio, suggesting that SNA is associated with abnormal breathing patterns. The WR, H/M ratio, plasma BNP level, and LVEF were significantly improved (WR, 40.0 ± 11.6% vs. 34.6 ± 11.4%, P = 0.046; H/M ratio, 1.5 ± 0.1 vs.1.8 ± 0.3, P = 0.013; ln BNP, 5.4 ± 1.0 vs. 4.6 ± 1.2, P = 0.007; and LVEF, 43.8 ± 10.4% vs. 47.0 ± 10.6%, P < 0.001) in the ASV group patients, but not in the non-ASV group patients. Multiple linear regression analyses showed that a decreased WR was strongly associated with an increased LVEF (coefficient = -0.454, P = 0.013).
  
  
  CONCLUSIONS
  Abnormal cardiac SNA could be significantly correlated with the severity of CSA in HF patients. ASV therapy might improve cardiac function in these patients by partially mediating cardiac SNA regulation.
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Akita University Graduate School of Medicine, Hondoh1-1-1, Akita, 010-8543, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Koyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Watanabe
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tamura
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Oguma
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Kosaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
mesh_terms: D000368:Aged; D015331:Cohort Studies; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D017286:Polysomnography; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D012720:Severity of Illness Index; D020182:Sleep Apnea, Central / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D016896:Treatment Outcome
keywords: Adaptive servo-ventilation; Cardiac sympathetic nerve activity; Heart failure; Sleep-disordered breathing; [123I]MIBG cardiac scintigraphy