Explorations into the development of a neurally regulated cardiac
pacemaker.
Ikeda, Yasuhiro, Masaru Sugimachi, Toji Yamasaki, Osamu Kawaguchi,
Toshiaki Shishido, Toru Kawada, Joe Alexander, Jr, *kenji Sunagawa.
Department of Cardiovascular Dynamics, National Cardiovascular
Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565,
JAPAN, Department of Biomedical Engineering, Vanderbilt University,
Nashville, Tennessee 37235
APStracts 2:0276H, 1995.
Although the artificial cardiac pacemaker has contributed to the
management of patients with serious arrhythmias, its rate responsive
function is not sufficient to provide physiological regulation of
heart rate (HR). To achieve truly physiological rate response in any
given patient, we propose a framework to develop a pacemaker directly
regulated by sympathetic nerve activity (SNA). In 8 anesthetized
rabbits, we quantified the dynamic transduction characteristics from
SNA to HR as a transfer function. We then characterized the decoding
rule as an impulse response, that is the transfer characteristics in
the time domain. The transfer function was approximated a first order
low pass filter with lag time (corner frequency: 0.024 ?? 0.012 Hz,
lag time: 0.98 0.09 second). Predicted HR correlated well with
measured HR (r=0.80-0.98). The standard error of the prediction
relative to mean heart rate was only 1.2 0.7 %, indicating that the
prediction was reasonably accurate. Direct decoding of SNA to predict
instantaneous HR is possible through this analysis. This framework
should enable development of a neurally regulated artificial
pacemaker.
Received 7 March 1995; accepted in final form 8 June 1995.
APS Manuscript Number H217-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.