title: Heart rate variability and hypercapnia in Duchenne muscular dystrophy.
abstract: OBJECTIVE
  To investigate the relationship between heart rate variability and hypercapnia.
  
  
  METHODS
  We measured the coefficient of variation of R-R interval (CVrr) and arterial blood gas pressures in 73 patients with Duchenne muscular dystrophy.
  
  
  RESULTS
  CVrr was negatively correlated with arterial partial pressure of carbon dioxide (PaCO(2)). In patients whose CVrr was larger than 5%, 84% of them had no hypercapnia while the other 16% had hypercapnia (PaCO(2) >45 mmHg). In contrast, 27% of those with CVrr smaller than 3% had no hypercapnia, 73% had hypercapnia and 47% had severe hypercapnia (PaCO(2) >50 mmHg).
  
  
  CONCLUSIONS
  We first showed that CVrr was negatively correlated with PaCO(2), and propose that abnormally low CVrr indicates respiratory insufficiency in patients with Duchenne muscular dystrophy.
authors.affiliation: Department of Neurology, Higashi-Saitama National Hospital, Hasuda. mochizuki-h@umin.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Satomi
authors.initials: S
authors.lastname: Okahashi
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
authors.forename: Takuhisa
authors.initials: T
authors.lastname: Tamura
authors.forename: Mikiya
authors.initials: M
authors.lastname: Suzuki
authors.forename: Satoko
authors.initials: S
authors.lastname: Miyatake
authors.forename: Toshiki
authors.initials: T
authors.lastname: Shigeyama
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Ogata
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kawai
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004562:Electrocardiography / Q000379:methods / Q000592:standards; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006935:Hypercapnia / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D020388:Muscular Dystrophy, Duchenne / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D055815:Young Adult