caa a22 4500 477118143 CHVBK 20180405111628.0 cr unu---uuuuu 170330e19961001xx s 000 0 eng 10.1007/BF02691433 doi (NATIONALLICENCE)springer-10.1007/BF02691433 Heart rate variability in the human transplanted heart: Nonlinear dynamics and QT vs RR-QT alterations during exercise suggest a return of neurocardiac regulation in long-term recovery [Elektronische Daten] [M. Meyer, C. Marconi, G. Ferretti, R. Fiocchi, P. Cerretelli, J. Skinner] Rationale. Functional reinnervation of the transplanted human heart by the autonomic nervous system has not been demonstrated. A lack of autonomic control of the transplanted allograft is reflected by an increased resting heart rate, a sluggish heart rate response to dynamical exercise and a reduced heart rate variability. Recent evidence suggests that a measure of deterministic chaos in the heartbeat interval series (point correlation dimension, PD2i) is superior to the conventional power spectrum or other stochastic measures in detecting changes in the mechanism underlying heartbeat generation.Methods. The PD2i is based on the presumption that the variability is determined and patterned, whereas the stochastic measures all assume that the variability is around a stationary mean and is noise. The PD2i reconstructs the degrees of freedom (number of independent variables) in the system that generates the time series examined, and does this irrespective of whether the system is stochastic or deterministic and is stationary in time.Results. PD2i was determined for heartbeat intervals (RR, ECG digitized at 1200 Hz; supine posture) of 23 heart transplant recipients (HTR: 9 adults, 14 children; 0.04-7.7 years after transplantation) and 21 healthy control subjects (CTL; 13 adults, 8 children). The PD2i (+/− SD) averaged 5.4 +/− 0.7 for the CTL adults and 5.4 +/− 0.6 for the CTL children. Mean PD2i was reduced after transplantation to 1.1 +/− 0.1 in 6 HTRs recorded within 1 year after surgery; in one HTR recorded 2 weeks after surgery the mean PD2i was 3.7. Between 1 to 2 years PD2i was found increased in 2 of 3 subjects and between 2 to 8 years it was increased in 13 of 13, but not to control levels. In normal hearts the QT subinterval of each heartbeat cycle is associated with inotropy and the RR-QT remainder with chronotropy (i.e., the dyastolic interval during which RR is primarily regulated). To examine more closely the residual and returning heartbeat dynamics of the HTR subjects, these subinterval series were examined during mild exercise (40 to 90 Watts) and its recovery. In recent HTRs, resting QT and RR-QT were moderately reduced and modulated by exercise and recovery, but with an approximate 100 beat latency. In long-term (7-8 years) HTR subjects there was a rapid and larger response to exercise/recovery, but compared to normal the range was smaller and the complexity of the subinterval trajectories in time was simpler.Conclusions. Recurrence of low-dimensional deterministic dynamics after transplantation suggests recovery of neurocardiac control attributable to 1) reorganization of the viable intrinsic cardiac nervous system, 2) reinnervation by the extrinsic autonomic nervous system, or 3) both. Transaction Publishers, 1996 autonomic nervous system nationallicence cardiac transplantation nationallicence correlation dimension nationallicence low-dimensional chaos nationallicence reinnervation nationallicence Meyer M. Department of Physiology, Max Planck Institute f. exp. Medicine, Gottingen, Germany aut Marconi C. Instituto di Tecnologie Biomediche Avanzate, CNR, Milano, Italy aut Ferretti G. Department de Physiologie, CMU, Geneve, Switzerland aut Fiocchi R. Ospedali Riuniti, Bergamo, Italy aut Cerretelli P. Instituto di Tecnologie Biomediche Avanzate, CNR, Milano, Italy aut Skinner J. Totts Gap Institute, Bangor, PA, USA aut Integrative Physiological and Behavioral Science Springer-Verlag 31/4(1996-10-01), 289-305 1053-881X 31:4<289 1996 31 12124 https://doi.org/10.1007/BF02691433 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02691433 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Meyer M. Department of Physiology, Max Planck Institute f. exp. Medicine, Gottingen, Germany aut NATIONALLICENCE 700 1- Marconi C. Instituto di Tecnologie Biomediche Avanzate, CNR, Milano, Italy aut NATIONALLICENCE 700 1- Ferretti G. Department de Physiologie, CMU, Geneve, Switzerland aut NATIONALLICENCE 700 1- Fiocchi R. Ospedali Riuniti, Bergamo, Italy aut NATIONALLICENCE 700 1- Cerretelli P. Instituto di Tecnologie Biomediche Avanzate, CNR, Milano, Italy aut NATIONALLICENCE 700 1- Skinner J. Totts Gap Institute, Bangor, PA, USA aut NATIONALLICENCE 773 0- Integrative Physiological and Behavioral Science Springer-Verlag 31/4(1996-10-01), 289-305 1053-881X 31:4<289 1996 31 12124 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer