Different evolutions in heart rate variability after heart transplantation: 10-year follow-up.
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.
Beckers
Frank
F
Laboratory of Experimental Cardiology, Department of Cardiology, University Hospital Gasthuisberg, K.U. Leuven, 3000 Leuven, Belgium.
Ramaekers
Dirk
D
Speijer
Gabrielle
G
Ector
Hugo
H
Vanhaecke
Johan
J
Verheyden
Bart
B
Van Cleemput
Johan
J
Droogné
Walter
W
Van de Werf
Frans
F
Aubert
André E
AE
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