title: Apnea-related heart rate variability and its clinical utility in congestive heart failure outpatients.
abstract: BACKGROUND
  Cheyne-Stokes breathing (CSB) is an abnormal cyclical pattern of respiratory fluctuations observed during sleep in congestive heart failure (CHF) of poor prognosis. We examined the clinical usefulness of CSB screening using the heart rate variability (HRV) data from the ambulatory electrocardiogram.
  
  
  METHODS
  We monitored ambulatory electrocardiograms and respiration simultaneously in 86 heart disease patients of both sexes, aged 57 +/- 1 years. HRV was analyzed by the maximum entropy method during the sleeping period (11 PM-5 AM). The 43 CHF patients underwent a 1-year follow-up study.
  
  
  RESULTS
  In the power spectra of the HRV, peaks were observed within the CSB band (0.005 to 0.03 Hz). Statistically significant differences in HRV were observed between CSB patients and CSB-free patients in very low frequency (VLF) (P = 0.04), VLF/total frequency (TF) (P = 0.02), CSB (P = 0.01), CSB/TF (P = 0.003), and CSB/VLF (P < 0.0001). Cardiac events occurred in 23% of patients, including cardiac death in two, and rehospitalization for aggravated CHF in eight. In a multivariate Cox regression analysis in which age, sex, ejection fraction, NYHA functional class, beta blocker use, and basic heart disease were included, absence of ACE inhibitor use (RR 5.5, 95% CI 1.0-31) and CSB/VLF > or =80% (RR 4.2, 95% CI 1.1-17) remained significant predictors of cardiac events.
  
  
  CONCLUSIONS
  HRV can act as an indicator of the presence of CSB in CHF patients, and could therefore be used, under outpatient conditions, to identify a CHF patients with a poor prognosis.
authors.affiliation: Central Clinical Laboratories Jikei University Kashiwa Hospital, 163-1 Kashiwashita, Kashiwa-shi, Chiba 277-8567 Japan. PBC01177@nifty.ne.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Tateishi
authors.forename: Toru
authors.initials: T
authors.lastname: Shouda
authors.forename: Youichi
authors.initials: Y
authors.lastname: Honda
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Sakai
authors.forename: Seibu
authors.initials: S
authors.lastname: Mochizuki
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Machida
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001049:Apnea / Q000503:physiopathology*; D002639:Cheyne-Stokes Respiration / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors