[Spectrum analysis of heart rate and arterial systolic pressure after heart transplantation in children].
The aim was to examine the short-term variability of blood pressure (BP) and heart rate (HR) in 19 children who had received heart transplants and in 8 normal control children. BP was determined by a finger arterial pressure device. We examined the power spectra for HR and systolic blood pressure (SBP) in the supine and standing posture. In the transplanted children we could distinguish two groups (groups A and B) in whom HR variability differed, though in both it was greatly reduced compared to controls (group C). In group A there were no significant fluctuations in the mid frequency (MF) range for HF. Gain of the relationship between SBP and HR was very low and there were virtually no HR changes associated with passive tilting. By contrast, in group B transplant patients the HR variability, as assessed by standard deviation was about half that of normal controls. The power spectra attenuation was greater in the high frequency (HF) than in the MF bands. On standing the latter became enhanced, but not the HF variability. The findings suggest some reinnervation involving cardiac sympathetic fibres to a greater degree than the fast-responding vagal fibres. Time since operation was a critical factor for reinnervation since all subjects from group B were transplanted more than 44 months prior to the recording. We conclude that in a proportion of children who have received heart transplantation there is a delayed reinnervation of the heart, which probably involves sympathetic effectors rather than the vagus.
Constant
I
I
Centre de pharmacologie clinique, association Claude-Bernard, CNRS URA 1482, Faculté de médecine Necker-Enfants Malades, Paris.
Girard
A
A
Le Bidois
J
J
Villain
E
E
Laude
D
D
Elghozi
J L
JL
D000367:Age Factors; D001794:Blood Pressure / Q000502:physiology*; D002648:Child; D006321:Heart / Q000294:innervation; D006339:Heart Rate / Q000502:physiology*; D016027:Heart Transplantation; D006801:Humans; D007024:Hypotension, Orthostatic / Q000503:physiopathology; D011184:Postoperative Period; D011187:Posture; D012815:Signal Processing, Computer-Assisted; D016683:Supine Position; D013599:Systole
Analyse spectrale de la fréquence cardiaque et de la pression artérielle systolique de l'enfant transplanté cardiaque.