ECG Acquisition and Automated Remote Processing

145 Pages·2014·2.56 MB·English

by  Rajarshi Gupta

Rajarshi Gupta · Madhuchhanda Mitra
Jitendranath Bera
ECG Acquisition
and Automated
Remote Processing
ECG Acquisition and Automated
Remote Processing
Rajarshi Gupta Madhuchhanda Mitra
•
Jitendranath Bera
ECG Acquisition
and Automated
Remote Processing
123
RajarshiGupta
MadhuchhandaMitra
Jitendranath Bera
Department of AppliedPhysics
Universityof Calcutta
Kolkata, WestBengal
India
ISBN 978-81-322-1556-1 ISBN 978-81-322-1557-8 (eBook)
DOI 10.1007/978-81-322-1557-8
SpringerNewDelhiHeidelbergNewYorkDordrechtLondon
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(cid:2)SpringerIndia2014
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Foreword
I am glad to note that a monograph entitled ‘‘ECG Acquisition and Automated
Remote Processing,’’ is published by M/s. Springer India. This is really a very
timely and state-of-the-art publication in the area of Biomedical Instrumentation.
Theauthorsofthismonographareagroupofdedicatedfacultymembersattached
to the ‘‘Biomedical SignalAcquisition and Processing’’ unit inthe Department of
Applied Physics, University of Calcutta.
If the twentieth century has seen spectacular advances in the area of Physical
Sciences,then thetwenty-first century isgoing tobedominated bythe Biological
Sciences.OneoftheveryimportantfocalareasintheBiologicalSciencesmustbe
related to Healthcare and Medical Science. As a consequence, a new multidisci-
plinary area of study has emerged, as Biomedical Engineering.
ModerndayBiologicalScienceandEngineeringhasbeenhighlydependenton
developments in Physics and Electrical Engineering, as has been found during
the last few decades. The advances in Electron Microscopy, Nuclear Magnetic
Resonance, Tomography, Laser Technology, Control Engineering, Solid State
Electronics, Computer Technology, Sensor Technology, Signal processing,
and Image processing are some of the areas that have immensely helped
Biomedical Researchers from both the therapeutic and diagnostic points of view.
Heart, being a vital and complex organ of the human body, needs special
attention for its monitoring. A very useful noninvasive technique to monitor
the activity of the heart system is to study the ECG signals and get analytical
information about its functioning.
This monograph is dedicated to the acquisition, analysis, and transmission of
electrical signals generated by the activities of the cardiovascular organ. ECG
signalsneedcomplexanalysistoextractusefulinformationaboutthehealthofthe
heart. Although for a pretty long time, it is being attempted to gather this infor-
mation for diagnostic purposes, shortcomings in the analytical tools create some
problems. This is why this topic has attracted the attention of researchers, world
over, who are equipped with such modern analytical tools to attack this problem.
Inthismonographtherearesixchaptersandattheendofeachindividualchapter
there are references, which give the future workers scope for study in this field.
v
vi Foreword
Students at the undergraduate and postgraduate levels in Biomedical Engineering
and Biomedical Instrumentation will find this monograph very useful for their
coursework.I mustthank the authors for their endeavor.
Kolkata, India, May 19, 2013 Prof. Dr. Dilip Kumar Basu
Former Vice Chancellor, Burdwan University
Bardhaman, West Bengal
India
Former Vice Chancellor, Tripura University
Agartala
India
Preface
Healthcare has been identified as one of the emerging areas of research in the
currentcentury.Inspiteoftheremarkabledevelopmentofscienceandtechnology
in the last four decades, the average mortality rates have increased in most
countries. Cardiovascular Diseases (CVD) remain as the dominant killer all over
theworld.AsperstatisticsfromWorldHealthOrganization(WHO),anestimated
17.3millionpeoplediedfromCVDin2008,representing30%ofallglobaldeaths.
Of these deaths, an estimated 7.3 million were due to coronary heart disease and
6.2 million were due to stroke. It is predicted that by the year 2030, 23.6 million
peoplewilldiefromCVDs,andtheworstaffectedregionwillbeSouthEastAsia.
Medical science has achieved significant progress in the recent years, mainly
contributed by research from bioinformatics, molecular biology, genetics, nano-
technology,drugresearch,andperipheralsciences.Asaresult,humancivilization
hasbeenabletooverpowermanyincurablediseases.Atthesametime,newerand
complex forms of diseases have come out and put tougher challenges before the
medical scientists.
Themarriagebetweenmedicalscienceandtechnologyhasgivenbirthtoanew
discipline,namedbiomedicalengineering, which iscontributedbysomecoreand
multidisciplinary engineering disciplines like Electrical, Electronics and Com-
munication, Instrumentation, Mechanical, and VLSI. Technologists have devel-
oped diagnostics tools and devices to extract pathological information from
patients and present them in a suitable format as an aid to the medical expert to
support his therapeutic actions. Electrocardiogram (ECG), the small potentials
generatedbytheheartmuscles,isperhapsthemostexploredmedicalsignalbythe
biomedical research community, due to its importance in overall healthiness of a
human being. Invention of the ECG machine by Willem Einthoven in the early
twentiethcenturyisconsideredasoneofthepioneeringlandmarksinthehistoryof
biomedical science. After that, various types of biomedical equipments and
deviceshavebeendevelopedwhicharecapableofprovidingaveryhighdegreeof
accuracy. A major impetus to this was development of imaging equipments like
ultrasonograph, computed tomography, etc., which are completely noninvasive in
nature.
Poor doctor to patient ratio is one of the persistent problem in the underde-
veloped and developing nations. Due to various socio-economic factors and lack
vii
viii Preface
of proper healthcare policies, the number of qualified medical professionals for
catering the need of rural patients is inadequate. A remedial measure toward this
problem was introduction of telehealth services, where the physician is supplied
with the medical signals from a remote patient using various communication
technologies.Inadvancednations,thisremotehealthcareserviceisnowastandard
practice extended to the remotest primary clinics in rural areas. However, in
developing nations this facility is not so widespread in regular service. Develop-
ment of smart, powerful, miniature devices is still an active area of research with
the objective ofeasy acquisition,fastprocessing,andseamless communication of
medicaldatatotheremoteendphysician.Inthecontextofdevelopingnationslike
India, easy operability and affordability are the key driving factors which should
drive the technology for delivering healthcare service to the general population.
Many Indian institutions are engaged in this area of research.
ThismonographisasmallandhumblecontributionfromtheBiomedicalSignal
Acquisition and Processing Research Group at Department of Applied Physics,
University of Calcutta, India. This book is written with the outcome of some
experimental developments of a prototype telecardiology system. The book is
addressed to a broad audience. It is expected to be useful to undergraduate and
postgraduate students of Biomedical Engineering, Electrical Engineering, Instru-
mentation Engineering, and researchers working in the similar area. One advan-
tageousfeatureforthereadersisthatallthealgorithmoutlinesarepresentedatthe
end of chapter appendix, so that new researchers can develop or customize their
own applications. A brief review of the main focal subjects is provided in the
respectivechapters.Thepublicationsfromourresearchgrouprelevanttothetopic
areindicatedattheendofeachchapter.Thisbookisonlymeanttocreateinterest
andinitiatemoreworkamongtheresearchersandcarrytheconceptfurther.Some
pictures, tables, and illustrations are reproduced from earlier publications and the
copyrights will rest with the original publishers.
The authors welcome comments and suggestions from the readers.
Kolkata, India Rajarshi Gupta
Madhuchhanda Mitra
Jitendranath Bera
Acknowledgments
The authors are thankful to the faculty members and staff of Department of
Applied Physics, University of Calcutta for the support and cooperation. The
experiments, a few results of which are shown in some chapters, are supported
by equipments purchased from Technical Education Quality Improvement Pro-
gramme (TEQIP) Phase-I at UCT, CU. Our research group received support
from SAP DRS-I programme from University Grants Commission (UGC) and
FIST project from Department of Science and Technology (DST), Government
of India. A special mention of Prof. Samarjit Sengupta, former Head, Depart-
ment of Applied Physics for his advice, encouragement, and close association
with our research group. The authors extend their thanks to Prof. Dilip Kumar
Basu, former Vice Chancellor, Tripura University, India for writing the Fore-
word of this book. The authors express their sincere gratitude to Springer India
for publication of this book.
Theauthorsalsoacknowledgethesupportreceivedfromtheirfamilymembers.
Rajarshi Gupta
Madhuchhanda Mitra
Jitendranath Bera
ix
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Heart and Cardiovascular System . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Genesis of the Electrocardiogram . . . . . . . . . . . . . . . . . . . . . . 3
1.4 ECG Clinical Signatures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 ECG Lead System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.6 ECG Recording. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.7 Evolution and Practice of Telemedicine and Telecardiology. . . . 10
1.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2 ECG Signal Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2 Computerized Analysis of ECG. . . . . . . . . . . . . . . . . . . . . . . . 15
2.3 Review on Computerized ECG Processing Techniques . . . . . . . 18
2.3.1 Denoising Techniques . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.3.2 R-peak Detection Methods. . . . . . . . . . . . . . . . . . . . . . 21
2.3.3 Feature Extraction from ECG Signal. . . . . . . . . . . . . . . 24
2.4 Method of ECG Signal Analysis. . . . . . . . . . . . . . . . . . . . . . . 26
2.4.1 QRS Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.4.2 Baseline Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.4.3 Determination of Fiducial Points. . . . . . . . . . . . . . . . . . 35
2.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3 ECG Acquisition in a Computer. . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.2 ECG Acquisition in a Clinical Setup . . . . . . . . . . . . . . . . . . . . 51
3.3 ECG Acquisition Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.3.1 ECG Signal Characteristics and Artifacts. . . . . . . . . . . . 52
3.3.2 Functional Blocks of a Digital ECG
Acquisition System. . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.3.3 ECG Amplifier and their Design Enhancements. . . . . . . 55
xi