title: Assessment of respiratory disturbance index determined with a non-restrictive monitor and of autonomic nervous system parameters in heart failure patients: A pilot study.
abstract: BACKGROUND
  There is a link between sympathetic overactivity and sleep-disordered breathing (SDB), and both of which are important indicators of the development of heart failure. To manage the increasing numbers of heart failure patients, any method used to check for them needs to be as non-invasive, simple, and cost-effective as possible. The purpose of this study is to assess screening of SDB with a non-restrictive monitor and the autonomic nervous system in heart failure patients.
  
  
  METHODS
  The subjects were 49 patients (mean age: 67 years; male: 78%) hospitalized for worsening heart failure. After stabilization with appropriate medical therapy, each patient simultaneously underwent sleep apnea syndrome (SAS) screening with the SD-101 (Kenzmedico Co. Ltd., Saitama, Japan), which is a novel, non-restrictive, sheet-like monitor for SAS screening, and assessment of heart rate variability (HRV) with a Holter monitor. In addition, we assessed daytime sleepiness by using the Epworth Sleepiness Scale.
  
  
  RESULTS
  The mean respiratory disturbance index (RDI) was 21.9 events/h. Males had significantly greater RDI values than females (24.5±11.2 events/h vs. 13.0±6.2 events/h, p<0.001). RDI on SD-101 testing was closely correlated with cyclic variation of heart rate index obtained with a Holter electrocardiogram scanner (r=0.843). Although plasma brain natriuretic peptide level was not correlated with HRV, plasma norepinephrine level was moderately well correlated with the total low- to high-frequency ratio of HRV (r=0.529).
  
  
  CONCLUSIONS
  SAS screening is important for heart failure patients, because absence of subjective sleepiness is not reliable in ruling out SDB. The SAS screening with SD-101 might apply for managing heart failure.
authors: Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Shuzo
authors: S
authors: Shimazu
authors: Department of Advanced Medicine in Cardiopulmonary Disease, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: hirasiki@med.nagoya-u.ac.jp.
authors: Akihiro
authors: A
authors: Hirashiki
authors: Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Yoshihiro
authors: Y
authors: Kamimura
authors: Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Yoshihisa
authors: Y
authors: Nakano
authors: Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Shiro
authors: S
authors: Adachi
authors: Department of Advanced Medicine in Cardiopulmonary Disease, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Takahisa
authors: T
authors: Kondo
authors: Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Toyoaki
authors: T
authors: Murohara
mesh_terms: D000368:Aged; D015716:Electrocardiography, Ambulatory; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007564:Japan; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation; D009638:Norepinephrine / Q000097:blood; D010865:Pilot Projects; D012737:Sex Factors; D012891:Sleep Apnea Syndromes / Q000175:diagnosis* / Q000503:physiopathology
chemical_list: D009638:Norepinephrine
keywords: Acute decompensated heart failure; Autonomic nervous activation; Heart rate variability; Screening; Sleep-disordered breathing