Assessment of heart rate variability and measurement of respiratory sinus arrhythmia

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)


Biomedical Engineering

First Committee Member

Joachim H. Nagel, Committee Chair


Heart rate (HR) fluctuations, or HR variability (HRV) reflect the effects of cardiac control activities. Analysis of HR variation patterns can provide information regarding the functioning of the autonomic nervous system (ANS) non-invasively. Respiration influences the cardiovascular system and contributes to a major component of HRV, which is referred to as Respiratory Sinus Arrhythmia (RSA). The analysis of HRV has found a variety of applications in medical diagnostics and monitoring as well as in physiological and behavioral studies.The engineering background of the techniques employed in previous studies for the analysis of HRV and the measurement of RSA have been reviewed. Existing methods for HR representation suffered from intrinsic inconsistencies with the underlying cardiac pacemaker model. The components of HRV with spectral overlap were unable to be separated by power spectral decomposition or filtering. None of the known techniques provided a continuous measurement of RSA, which would be desirable for studies of transient or dynamic responses.This dissertation provides novel solutions to these problems: a new technique for the derivation of a continuous representation of HR, an adaptive filtering system for the decomposition of HRV and an envelope index of a quasi-oscillatory waveform for the continuous measurement of RSA. The advantages of these methods over those employed in previous studies have been demonstrated through simulations. A systematic procedure for the analysis of HRV and the measurement of RSA has been established. The procedure has been evaluated for the estimation of parasympathetic cardiac control through animal and human experiments. This procedure can separate the components of HRV in terms of optimal filtering and has the unique ability to provide a continuous measurement of RSA for psychophysiological and medical studies.


Engineering, Biomedical; Psychology, Physiological

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