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njit-etd2003-081 - New Jersey Institute of Technology

njit-etd2003-081 - New Jersey Institute of Technology

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ABSTRACT<br />

TIME-FREQUENCY INVESTIGATION OF HEART RATE VARIABILITY AND<br />

CARDIOVASCULAR SYSTEM MODELING OF NORMAL AND CHRONIC<br />

OBSTRUCTIVE PULMONARY DISEASE (COPD) SUBJECTS<br />

by<br />

Douglas A. <strong>New</strong>andee<br />

A study has been designed to add insight to some questions that have not been fully<br />

investigated in the heart rate variability field and the cardiovascular regulation system in<br />

normal and Chronic Obstructive Pulmonary Disease (COPD) subjects. It explores the<br />

correlations between heart rate variability and cardiovascular regulation, which interact<br />

through complex multiple feedback and control loops. This work examines the coupling<br />

between heart rate (HR), respiration (RESP), and blood pressure (BP) via closed-loop<br />

system identification techniques in order to noninvasively assess the underlying<br />

physiology.<br />

In the first part <strong>of</strong> the study, the applications <strong>of</strong> five different bilinear timefrequency<br />

representations are evaluated on modeled HRV test signals, actual<br />

electrocardiograms (ECG), BP and RESP signals. Each distribution: the short time<br />

Fourier transform (STFT), the smoothed pseudo Wigner-Ville (SPWVD), the Choi-<br />

Williams (CWD), the Born-Jordan-Cohen (BJC) and wavelet distribution (WL), has<br />

unique characteristics which is shown to affect the amount <strong>of</strong> smoothing and the<br />

generation <strong>of</strong> cross-terms. The CWD and the WL are chosen for further application<br />

because <strong>of</strong> overcoming the drawbacks <strong>of</strong> other distributions by providing higher<br />

resolution in time and frequency while suppressing interferences between the signal<br />

components.

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