title: Fractal dimension in health and heart failure.
abstract: BACKGROUND
  Non-linear analysis of heart rate variability (HRV) can give additional information about autonomic control of the heart rate. This study applied the fractal dimension (FD) in a congestive heart failure (CHF) population.
  
  
  METHODS
  FD and HRV were evaluated in a healthy population (n=21) and an end-stage heart failure population (n=21) using 1-h segments during the day and night from Holter recordings.
  
  
  RESULTS
  CHF patients presented a loss of circadian variation in both FD and conventional time- and frequency-domain HRV indices. FD was higher in the CHF population both during the day and night. In the CHF population the correlation between FD and high-frequency power of HRV was lost.
  
  
  CONCLUSIONS
  Day-night variations of heart rate fluctuations are lost in heart failure. Changes in FD reflecting physiological and pathophysiological changes were observed.
authors.affiliation: Laboratory of Experimental Cardiology, Department of Cardiovascular Diseases, University Hospital Gasthuisberg, Leuven, Belgium. frank.beckers@med.kuleuven.be
authors.forename: Frank
authors.initials: F
authors.lastname: Beckers
authors.forename: Bart
authors.initials: B
authors.lastname: Verheyden
authors.forename: Kurt
authors.initials: K
authors.lastname: Couckuyt
authors.forename: André E
authors.initials: AE
authors.lastname: Aubert
mesh_terms: D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D001683:Biological Clocks; D002940:Circadian Rhythm; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D017709:Fractals; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009991:Oscillometry / Q000379:methods