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DYNAMICAL SYSTEM APPROACH TO HEART RATE VARIABILITY:
QT VERSUS RR INTERVAL
by
Fariba Ariaei
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(ELECTRICAL ENGINEERING)
December 2008
Copyright 2008 Fariba Ariaei
Object Description
| Title | Dynamical system approach to heart rate variability: QT versus RR interval |
| Author | Ariaei, Fariba |
| Author email | ariaei@usc.edu; fariba.ariaei@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Electrical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2008-09-08 |
| Date submitted | 2008 |
| Restricted until | Restricted until 16 Dec. 2010. |
| Date published | 2010-12-16 |
| Advisor (committee chair) | Jonckheere, Edmond A. |
| Advisor (committee member) |
Nayak, Krishna S. Hsiai, Tzung K. |
| Abstract | Heart dynamics and heart rate variability, as well as their characterization, have been of interest to researchers for years. Sudden death due to heart failure, which could be the result of heart diseases, drug consumptions, or even emotional shocks, is one of the most important issues in public health. Henceforth, prediction and/or awareness of such conditions has always been a top priority. In the present work, a time domain approach, as opposed to the traditional frequency-domain approach, to heart rate dynamics is introduced. The Electro-Cardio-Gram (ECG) signals, more specifically the RR and QT intervals as characteristics of heart dynamics, are investigated. It is hypothesized that the Erlang distribution of the RR interval is a manifestation of the Poincaré return time phenomenon, and based on clinical results available to us, it is conjectured that for the healthy heart, it is necessary but not sufficient that the RR interval would be the k-fold Poincaré return time. The higher frequency, k times that of normal heartbeat, is hypothesized to be related to the synchronization of the array of pacemaker cells in the sinoatrial (SA) node. In this work, chaotic behavior of heart dynamics is observed by means of such nonlinear techniques such as calculation of Lyapunov exponents, Kolmogorov-Sinai (KS) entropy, and Kaplan-Yorke (K-Y) dimensions. These techniques measure chaos, the amount of uncertainty and complexity of the system, respectively. The existence of positive Lyapunov exponent and non-integer K-Y dimension in the heart rate confirms its chaotic dynamics. Heart dynamics is also analyzed via statistical techniques such as linear and nonlinear canonical correlation analyses and mutual KS information. These techniques are implemented to unravel the at point subtle relationship between RR and QT intervals.; It is conjectured that past RR intervals are nonlinear regression variables on the future QT intervals for the healthy heart, and in case of any abnormalities, such as prolongation of QT interval, the cause to effect relationship from past RR to future QT might be compromised. |
| Keyword | chaos; dynamical systems; Kolmogorov-Sinai entropy; ergodic theory; heart rate variability; information theory |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m1929 |
| Rights | Ariaei, Fariba |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Ariaei-2542 |
| Archival file | uscthesesreloadpub_Volume26/etd-Ariaei-2542.pdf |
Description
| Title | Page 1 |
| Full text | DYNAMICAL SYSTEM APPROACH TO HEART RATE VARIABILITY: QT VERSUS RR INTERVAL by Fariba Ariaei A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (ELECTRICAL ENGINEERING) December 2008 Copyright 2008 Fariba Ariaei |
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