title: Different evolutions in heart rate variability after heart transplantation: 10-year follow-up.
abstract: BACKGROUND
  After heart transplantation, the donor heart is extrinsically denervated. No input of sympathetic or vagal nerves can influence the heart rate, resulting in a flat power spectrum of the beat-to-beat variability. The occurrence and the significance of reinnervation remain controversial.
  
  
  RESULTS
  We monitored the evolution of heart rate variability (HRV) after heart transplantation, starting from a few weeks postoperatively up to 10 years after surgery. Twenty-four-hour Holter recordings of 216 heart-transplant patients were analyzed using time and frequency domain analysis of HRV. Analysis of all data revealed an increase in 24-hour and night-time total power starting from 2 years after transplantation. Low-frequency oscillations calculated over the total 24 hours, day- and nighttime increased significantly starting from year 4 and onward (year 4-8: P < 0.005). No evolution was found in high-frequency power. Subgroup analysis revealed a group with a clear spectral component (n = 16), a group with a small component (n = 124), and a group with a flat spectrum (n = 76). Only the first group revealed an evolution in both high- and low-frequency power.
  
  
  CONCLUSIONS
  These results indicate three different types of evolution in HRV, with reinnervating patterns present in only a minority of the patients. The vast majority of the patients show no signs of reinnervation.
authors.affiliation: Laboratory of Experimental Cardiology, Department of Cardiology, University Hospital Gasthuisberg, K.U. Leuven, 3000 Leuven, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Beckers
authors.forename: Dirk
authors.initials: D
authors.lastname: Ramaekers
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Speijer
authors.forename: Hugo
authors.initials: H
authors.lastname: Ector
authors.forename: Johan
authors.initials: J
authors.lastname: Vanhaecke
authors.forename: Bart
authors.initials: B
authors.lastname: Verheyden
authors.forename: Johan
authors.initials: J
authors.lastname: Van Cleemput
authors.forename: Walter
authors.initials: W
authors.lastname: Droogné
authors.forename: Frans
authors.initials: F
authors.lastname: Van de Werf
authors.forename: André E
authors.initials: AE
authors.lastname: Aubert
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D002940:Circadian Rhythm; D015716:Electrocardiography, Ambulatory / Q000379:methods; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D012189:Retrospective Studies; D013997:Time Factors