title: [Circadian periodicity in human heart rate daily variability disorders: subsequent demonstrations through a chronobiological approach to the values of estimated alpha exponent on sinusal R-R intervals].
abstract: OBJECTIVE
  The present study is aimed at giving a further demonstration that the disorder in human heart rate variability is characterized by a circadian periodicity. Such an evidence has been provided by estimating the alpha exponent of the Lévy's stable distribution approximated to the histogram of the differences between the durations of two adjacent sinusal R-R intervals.
  
  
  METHODS
  The purpose has been pursued by estimating the alpha exponent on fragments of one hour of the Holter electrocardiogram executed in 10 clinically healthy subjects (5 males and 5 females, ranging in age from 23 to 30 years).
  
  
  RESULTS
  The chronobiological analysis of the hourly-qualified values of the alpha exponent has demonstrated a significant circadian rhythm for this coefficient.
  
  
  CONCLUSIONS
  The significant circadian periodicity of the alpha exponent is a further evidence that the disorder in human heart rate variability, herein represented by the extreme variability of the differences between the durations of two consecutive sinusal R-R intervals, is characterized by a periodic recursivity.
authors.affiliation: Dipartimenti di Scienze Cliniche, Università di Roma La Sapienza, Roma, Italia.
authors.forename: P
authors.initials: P
authors.lastname: Cugini
authors.forename: C
authors.initials: C
authors.lastname: Cammarota
authors.forename: M
authors.initials: M
authors.lastname: Curione
authors.forename: D
authors.initials: D
authors.lastname: Cipriani
authors.forename: R
authors.initials: R
authors.lastname: De Rosa
authors.forename: P
authors.initials: P
authors.lastname: Francia
authors.forename: E
authors.initials: E
authors.lastname: De Marco
mesh_terms: D000328:Adult; D002909:Chronobiology Phenomena; D002940:Circadian Rhythm; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male