WE−FORMANALYSISOFELECTROCARDIOGRAPHWITHSPECTRUMFORSCREENINGTEST

Shigehiro＝ashimoto】，NaoyaAmimotol，HiroshiOkul，

HqjimeOtani2，HirqliImamura2】BiomedicalSystems，Dept・OfElectronics，InfbrmationandCommunicationEngineerlng，OsakaInstituteofTeclmology，Osaka，Japan，hasimotoraelc．oit．ac．jl）

2Dept・OfThoracicandCardiovascularSurgery，KansaiMedicalUniversity
INTRODUCTION

betweenlandlO Hz during P−Qinterval，Whileit was

Electrocardiogram（ECG）renects the conduction ofaction

distributedlHzand40Hzinthewholecardiaccycle．This
isbecausethesteepestwaveoccursinQRScomplex．

potentialintheheart．ECG consists ofseveralelements ofelectronic eventsin the heart．ECG was widely used fbr
diagnosticsoftheheartdiseaseasanoninvasivemarker・To

get enoughinfbrmation directly from the ECG traclngS，
enough trainlngis necessary fbr aninterpreter．Several
COmputer−aidedmethods（Arthur，R．M．（1995），Kinoshita，0．
（1992））includingR−Rintervaldetectionhavebeendesigned
inthepreviousstudies，lbextenditsusetothehealth−Caredeviceathome，aSimplemethodologywithspectrumanalysIS
to distinguishirregular conduction from normalone wasinvestlgatedinthisstudy．
METHODSIn the data both with compensatory ventricular premature
contraction and with interpolated ventricular premature
COntraCtion，thespectrumSlgnincantlydecreasedbetween20
Hzand40Hz．ThisisbecauseoftheextensionofQRSwave
Width．Timingofirregularwaveinthecardiaccycledidnot
afftctthespectrumdistribution，
TheR−RintervalanalysISisusefu1todetectarrhythmiabutis
not usefu1to detect wave modincationin a pre−eXCitation
Symdrome．Theproposedmethodhasenoughavailabilityto
detectECGwavechangeinheartdisease，andcanbeapplied
to screening test in diagnosis for ventricular premature
COntraCt10n．

The electrocardiogram（ECG）wasinduced between theleft

ankle and the right wrist．The electrodes of disk type（diameterof8mm）wヲreStuCkvia．

electromyogram．Afterthe slgnalwas modified sothatthefrequencieslowerthanO．08HzorhigherthanlkHzwerecut

SUMMARY

This paper proposes a simplified methodology to detect
irregularconductionofpotentialsinheartduringcardiaccycle
uslngSPeCtrumanalysISOfelectrocardiogram．

Offthrough the electricⅢter，it was convertedinto digital

Slgnalwiththesamplingrateof256Hz，andrecordedwitha
PerSOnalcomputer．ThesegmentedECGdataofonesecond
betweenPwaveandTwavewereanalyzedwithfastFourier

REFERENCES

transform（FFT）．Data atthebaseline ofECGwere addedg〃g，42，29−41before Pwave，When the cyclic periodwas shorterthan one

Kinoshita，0．，Kamakura，S．etal（1992）．Cift7ulalioT7，85（6），second．

2054−2059．

Nomla130segmentsofregularslgnalwerecollectedftomnve

ACKNOWLEDGEMENTS

Arthur，R．MリKavesh，N．G．，etal（1995）．1EEETTansBiomed

VOlunteerhumansu切ectsbetween21and25yearsoldatrest．

Somesegmentsofirregularslgnalwerepickedupfromthesemeasurements，and the data with compensatory ventricularpremature contraction or with interpolated ventricular
PrematureCOntraCtionwereanalyzed．
RESULTS AND DISCUSSION

The ECG spectrum decreases fiom20Hz to40Hz．TheECGspectrumCanberepresentedwiththerangefromlHzto
60Hz．

Thedataweredisplayedinthethree−dimensionalngure，WhentheintervalofanalysISWaSeXtendedgraduallyfromPwaveto
TwavewithastepofO．04s．Thespectrumatthetime of

OneSeCOndshowsdatumatthewholecardiaccycle．
Inthedata斤omanormalECG，thespectrumWaSdistributed

This work was supportedin part by a Grant−inTAid for
ScientincResearchfromtheJapaneseMinistryofEducation，Culture，Sports，ScienceandTechnology・