title: Ambulatory ECG and analysis of heart rate variability in Parkinson's disease.
abstract: OBJECTIVE
  Cardiovascular reflex tests have shown both sympathetic and parasympathetic failure in Parkinson's disease. These tests, however, describe the autonomic responses during a restricted time period and have great individual variability, providing a limited view of the autonomic cardiac control mechanisms. Thus, they do not reflect tonic autonomic regulation. The aim was to examine tonic autonomic cardiovascular regulation in untreated patients with Parkinson's disease.
  
  
  METHODS
  24 Hour ambulatory ECG was recorded in 54 untreated patients with Parkinson's disease and 47 age matched healthy subjects. In addition to the traditional spectral (very low frequency, VLF; low frequency, LF; high frequency, HF) and non-spectral components of heart rate variability, instantaneous beat to beat variability (SD1) and long term continuous variability (SD2) derived from Poincaré plots, and the slope of the power law relation were analysed.
  
  
  RESULTS
  All spectral components (p<0.01) and the slope of the power-law relation (p<0.01) were lower in the patients with Parkinson's disease than in the control subjects. The Unified Parkinson's disease rating scale total and motor scores had a negative correlation with VLF and LF power spectrum values and the power law relation slopes. Patients with mild hypokinesia had higher HF values than patients with more severe hypokinesia. Tremor and rigidity were not associated with the HR variability parameters.
  
  
  CONCLUSIONS
  Parkinson's disease causes dysfunction of the diurnal autonomic cardiovascular regulation as demonstrated by the spectral measures of heart rate variability and the slope of the power law relation. This dysfunction seems to be more profound in patients with more severe Parkinson's disease.
authors.affiliation: Department of Neurology, University of Oulu, PO Box 5000, 90014 University of Oulu, Finland. Tarja.Haapaniemi@oulu.fi
authors.forename: T H
authors.initials: TH
authors.lastname: Haapaniemi
authors.forename: V
authors.initials: V
authors.lastname: Pursiainen
authors.forename: J T
authors.initials: JT
authors.lastname: Korpelainen
authors.forename: H V
authors.initials: HV
authors.lastname: Huikuri
authors.forename: K A
authors.initials: KA
authors.lastname: Sotaniemi
authors.forename: V V
authors.initials: VV
authors.lastname: Myllylä
mesh_terms: D000368:Aged; D002940:Circadian Rhythm / Q000502:physiology; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*