title: Explorations into development of a neurally regulated cardiac pacemaker.
abstract: 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 eight 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 by a first-order, low-pass filter with lag time (corner frequency: 0.024 +/- 0.013 Hz, lag time: 0.98 +/- 0.09 s). Predicted HR correlated well with measured HR (r = 0.80-0.98). The standard error of the prediction relative to mean HR 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.
authors.affiliation: Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
authors.forename: M
authors.initials: M
authors.lastname: Sugimachi
authors.forename: T
authors.initials: T
authors.lastname: Yamasaki
authors.forename: O
authors.initials: O
authors.lastname: Kawaguchi
authors.forename: T
authors.initials: T
authors.lastname: Shishido
authors.forename: T
authors.initials: T
authors.lastname: Kawada
authors.forename: J
authors.initials: J
authors.lastname: Alexander
authors.forename: K
authors.initials: K
authors.lastname: Sunagawa
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D005544:Forecasting; D006339:Heart Rate; D006439:Hemodynamics; D008955:Models, Cardiovascular; D010138:Pacemaker, Artificial; D011817:Rabbits