Continuous electrode contact impedance estimation for electrocardiography
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Journal Title
Journal ISSN
Volume Title
Sähkötekniikan korkeakoulu |
Master's thesis
Authors
Date
2018-10-08
Department
Major/Subject
Control, Robotics and Autonomous systems
Mcode
ELEC3025
Degree programme
AEE - Master’s Programme in Automation and Electrical Engineering (TS2013)
Language
en
Pages
59+1
Series
Abstract
This thesis presents a method to be used in development of an advisory system for new electrocardiography monitors by General Electric that assists clinicians to record accurate and reliable data from ECG device by maintaining electrode contact quality with patient's skin. This thesis aims at developing a continuous electrode contact quality estimation method based on the provided continuous electrode contact impedance monitoring circuit for 6-lead ECG setup. This thesis further investigates accuracy of the proposed method. The continuous electrode contact impedance monitoring circuit injects a sinusoidal signal into each electrode input path and measures output differential voltage from an ECG channel. The circuit does not provide any direct information regarding electrode contact quality. A method is presented that estimates contact impedance of electrodes based on magnitude and phase of measured output voltage, which is further used to determine magnitude of electrode impedance reflecting the contact quality of electrodes with body. Analytical approach to determine contact impedance of electrodes is also investigated in this thesis. Another major portion of this thesis is comprised of developing the simulation circuit by mimicking the circuit from provided actual measurement setup. Data collected from actual setup and simulation circuits has been analysed to determine accuracy of the proposed method in order to differentiate between good and poorly connected electrodes. The effect of high impedance of electrodes other than the electrode under test has also been investigated. Additionally, monte carlo circuit simulations have been performed to determine the reliability of electrode contact impedance estimation method based on tolerance values of circuit components. Results presented in this work validate the accuracy and reliability of the presented method so that it can be used in further research for the development of advisory system regarding ECG electrodes for clinicians.Description
Supervisor
Paulasto-Kröckel, MerviThesis advisor
Virtanen, JuhaKeywords
electrocardiogram, right leg drive, electrode contact impedance, defibrillation, ambulatory