title: Compensatory properties of heart rate asymmetry.
abstract: BACKGROUND
  Heart rate asymmetry (HRA) is a physiologic phenomenon that reflects a systematic and 1-directional difference between heart rate accelerations and decelerations. In terms of variance-based descriptors, HRA causes the contributions from heart rate decelerations to contribute more to short-term variability than accelerations, and for the long-term variability, the relation is reversed. The hypothesis tested in the present article is that this reversal is caused by a compensatory mechanism whose function is to keep the system in relative balance.
  
  
  METHODS
  Thirty-minute electrocardiographic recordings from 420 young healthy volunteers were analyzed. The variance-based HRA descriptors were calculated. Cases with both short- and long-term HRAs were considered to show compensation. In the binomial test, we looked for statistically significant departures from independence in the distribution of cases possessing both types of asymmetry.
  
  
  RESULTS
  Short-term asymmetry was observed in 77.6% of subjects (P < .0001), and long-term asymmetry, in 69.3% (P < .0001); both types of HRA coexisted in 66.9% (P < .0001) of the whole group. This result is significantly different (P < .0001) from the independent case (53.78%).
  
  
  CONCLUSIONS
  The compensation effect between the short- and long-term asymmetries is present in supine resting electrocardiographic recordings in young healthy people.
authors.affiliation: Institute of Physics, University of Zielona Gora, Zielona Gora, Poland. jaropis@zg.home.pl
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Piskorski
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Guzik
mesh_terms: D000328:Adult; D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult