Complex neurophysiological systems exhibit many types of dynamical behavior that indicate the presence of nonlinear mechanisms, including i) fractal (chaotic) fluctuations, which are characterized by l/f-like spectra, positive Lyapunov exponents and finite correlation dimension; ii) abrupt changes (bifurcations); and iii) sustained oscillations. Recently developed methods of nonlinear mathematics might be appropriate to identify and analyze such nonlinear dynamical behavior, but the suitability of those methods for the analysis of neurophysiological data needs to be demonstrated. We have found that beat-to-beat fluctuations in heart rate provide a readily accessible model system for investigating the variety of nonlinear dynamics in a neuroautonomic network, and the general aim of this proposal is to evaluate the applicability of the nonlinear methodology to that data. Fluctuations in cardiac interbeat interval, which are modulated by parasympathetic-sympathetic interactions, will be recorded for 24 hour time periods and will then be subjected to digital signal processing for spectral analysis, phase space mapping, and calculation of fractal dimension and other nonlinear metrics.
Our aim i s to determine whether these analytical methods demonstrate the presence of nonlinear neuroautonomic control processes. Specifically, we propose: 1. To test the hypothesis that heartrate regulation in healthy individuals is governed by fractal (chaotic) neuroautonomic control mechanisms. 2. To test the hypothesis that a variety of dysfunctions result in heartrate data that exhibit bifurcations, nonlinear oscillations and the loss of fractal variability. 3. To develop a nonlinear mathematical neurophysiological model of neuroautonomic heartrate control that accounts for the fractal variability of normal heartrate fluctuations and for the bifurcations and oscillatory behavior actually observed under certain pathologic conditions.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL042172-03
Application #
3360267
Study Section
Special Emphasis Panel (SSS (C))
Project Start
1989-01-01
Project End
1992-12-31
Budget Start
1991-01-01
Budget End
1992-12-31
Support Year
3
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Beth Israel Deaconess Medical Center
Department
Type
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
02215
Goldberger, A L; Mietus, J E; Rigney, D R et al. (1994) Effects of head-down bed rest on complex heart rate variability: response to LBNP testing. J Appl Physiol 77:2863-9
Pincus, S M; Goldberger, A L (1994) Physiological time-series analysis: what does regularity quantify? Am J Physiol 266:H1643-56
Vybiral, T; Glaeser, D H; Goldberger, A L et al. (1993) Conventional heart rate variability analysis of ambulatory electrocardiographic recordings fails to predict imminent ventricular fibrillation. J Am Coll Cardiol 22:557-65
Hausdorff, J M; Forman, D E; Pilgrim, D M et al. (1992) A new technique for simultaneous monitoring of electrocardiogram and walking cadence. Am J Cardiol 70:1064-71
Lipsitz, L A; Goldberger, A L (1992) Loss of 'complexity' and aging. Potential applications of fractals and chaos theory to senescence. JAMA 267:1806-9
Manning, W J; Goldberger, A L; Drews, R E et al. (1992) POEMS syndrome with myocardial infarction: observations concerning pathogenesis and review of the literature. Semin Arthritis Rheum 22:151-61
Krumholz, H M; Goldberger, A L (1991) Reperfusion arrhythmias after thrombolysis. Electrophysiologic tempest, or much ado about nothing. Chest 99:135S-140S
Goldberger, A L (1991) Is the normal heartbeat chaotic or homeostatic? News Physiol Sci 6:87-91
Stambler, B S; Morgan, J P; Mietus, J et al. (1991) Cocaine alters heart rate dynamics in conscious ferrets. Yale J Biol Med 64:143-53
Nelson, T R; West, B J; Goldberger, A L (1990) The fractal lung: universal and species-related scaling patterns. Experientia 46:251-4

Showing the most recent 10 out of 12 publications