Utility of the surface electrocardiogram forWord格式文档下载.docx
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acceptedafterrevision11August2010
AimsWhentargetingtheinterventricularseptumduringpacemakerimplantation,theleadmayinadvertentlybepositioned
ontheanteriorwallduetoimprecisefluoroscopiclandmarks.Surfaceelectrocardiogram(ECG)criteriaofthepaced
QRScomplex(e.g.negativityinleadI)havebeenproposedtoconfirmaseptalposition,butthesecriteriahavenot
beenproperlyvalidated.OuraimwastoinvestigatewhetherthepacedQRScomplexmaybeusedtoconfirmseptal
leadposition.
MethodsAnatomicalreconstructionoftherightventriclewasperformedusingaNavX
w
systemin31patients(70+11years,
26males)tovalidatepacingsites.Surface12-leadECGswereanalysedbydigitalcallipersandcomparedwhilepacing
fromapara-Hissianposition,fromthemid-septum,andfromtheanteriorfreewall.
ResultsDurationoftheQRScomplexwasnotsignificantlyshorterwhenpacingfromthemid-septumcomparedwiththe
othersites.QRSaxiswassignificantlylessverticalduringmid-septalpacing(18+518)comparedwithparaHissian(38+378,P¼
0.028)andanterior(53+558,P¼
0.003)pacing,andQRStransitionwasintermediate
(4.8+1.3vs.3.8+1.3,P,0.001,andvs.5.4+0.9,P¼
0.045,respectively),althoughnocut-offscouldreliablydistinguishsites.AnegativeQRSorthepresenceofaq-waveinleadItendedtobemorefrequentwithanteriorthan
withmid-septalpacing(9/31vs.3/31,P¼
0.2and8/31vs.1/31,P¼
1.0,respectively).
ConclusionNosingleECGcriterioncouldreliablydistinguishpacingthemid-septumfromtheanteriorwall.Inparticular,anegativeQRScomplexinleadIisaninaccuratecriterionforvalidatingseptalpacing.
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KeywordsPacing†Ventricle†Interventricularseptum†Electrocardiogram†Electroanatomicalmapping
Introduction
Fordecades,ventricularpacinghasbeenperformedfromtheapex
oftherightventricle(RV),becauseofeaseofimplantationandlead
stabilityatthissite.ConventionalRVapicalpacing,becauseofdyssynchronousleftventricularcontraction,mayhavedetrimental
effectsoncardiacstructureandpumpfunction.
1,2
Randomized
trialshavereportedthatRVapicalpacingincreasesincidenceof
heartfailureandatrialfibrillation.
3,4
Theseobservationshaveled
toaninterestinalternativerightventricularpacingsites,
5
suchas
therightventricularoutflowtract(RVOT)andthemid-septum,
topromotemorephysiologicalventricularactivation.However,
targetingtheseptummaybetechnicallychallengingasitis
mainlybasedonfluoroscopy,withoutreliablelandmarksin
patientswithvariablechambersizeandcardiacorientation.In
thesinglestudyvalidatingleadpositionusingechocardiography,
Ngetal.
6
showedthatdespiteusingobliquefluoroscopicviews
forplacingtheleadontheseptum,thefinalpositionwasheterogeneous,withtheleadbeingsometimespositionedontheanterior
freewallorintheanterioroutflowtract.Thisismostprobablydue
totendencyoftheleadtofallforwardasitiswithdrawnfromthe
pulmonaryarteryduringimplantationwithastandardmanually
curvedstylet.Pacingfromananteriorsiteshouldbeavoidedas
itmayresultinadverseeffectssuchasreducedleftventricular
*Correspondingauthor.Tel:
+41223727200;
fax:
+41223727229,Email:
haran.burri@hcuge.ch
PublishedonbehalfoftheEuropeanSocietyofCardiology.Allrightsreserved.&
TheAuthor2010.Forpermissionspleaseemail:
journals.permissions@oxfordjournals.org.
Europace
doi:
10.1093/europace/euq332
EuropaceAdvanceAccesspublishedSeptember9,2010
atUniversidadeFederaldoAmazonasonSeptember12,2010europace.oxfordjournals.orgDownloadedfromsystolicfunction
orcardiactamponnade,
7
andmayalsocarrya
riskofdamagetotheleftanteriordescendingartery.
8
Surfaceelectrocardiogram(ECG)criteriaofthepacedQRS
complex(e.g.anegativeQRScomplexinleadI)havebeenproposedtoconfirmanRVOTseptalposition.
5,9–11
However,the
ECGcriteriainthesestudieshavenotbeenproperlyvalidated,
asactualleadpositionwasnotconfirmedbyanyimagingtechnique
otherthanper-proceduralfluoroscopyorasimplechestX-ray.
Also,itisunknownwhetherthesecriteriaapplytoamid-septal
pacingsite,whichislowerandmorerightwardthantheRVOT
septum.
TheaimofourstudywastoidentifyECGcriteriaduringRV
pacingthatconfirmamid-septalpositionanddifferentiatethis
sitefromtheanteriorfreewall,usingelectroanatomicalmapping
tovalidatepacingsites.
Methods
Patientpopulation
Atotalof31consecutivepatientsfromtwocentresinGeneva
(UniversityHospitalandLaTourHospital),whowerescheduled
toundergoradiofrequencyablationofisthmus-dependentatrial
flutter,wereprospectivelyenrolledinthestudy.PatientdemographicsareshowninTable1.
Allpatientsgaveinformedconsenttoparticipateinthestudy,
whichwasapprovedbytheInstitutionalEthicsCommittee.
Mappingprotocol
Patientswerestudiedinafastingandsedatedstate.Twocatheters
wereintroducedpercutaneouslythroughtherightfemoralvein.A
6-Frenchquadripolardiagnosticcatheter(BardElectrophysiology,
Lowell,MA,USA)wasadvancedtotherightatriumandan
irrigated-tip3.5mmablationcatheter(ThermoCoolFcurve,BiosenseWebster,DiamondBar,CA,USAorTherapyCoolPathFL
curve,StJudeMedical,StPaul,MN,USA)wasusedforperforming
cavo-tricuspidisthmusablation.Afterobtainingbidirectionalblock
ofthecavo-tricuspidisthmus,anatomicalreconstructionoftheRV
wasperformedusingtheEnSiteNavX
system(StJudeMedical).
Thequadripolardiagnosticcatheterwasusedasthereferenceand
positionedinastablepositionintherightatrium(ratherthanin
theventricle,soastoavoiddisplacementwhenmanipulatingthe
mappingcatheter),withcreationofa‘shadow’tomonitordisplacement.TheablationcatheterwasmanoeuvredintheentireRV
forgeometricalreconstruction.Theplaneofthepulmonary
valvewasdefinedbyadvancingthemappingcatheterinthe
RVOTuntilnodiscretebipolarelectrogramswererecordedin
thedistalelectrode,andthetricuspidvalvewasdefinedbyequal
amplitudesofatrialandventricularelectrograms.TheHisbundle
wasannotatedattheonsetofmapping,anditslocationchecked
attheendofthepacingprotocol,inordertoverifytheabsence
ofreferenceshiftduringthestudy(inadditiontoverifyingthe
shadowofthequadripolarreferencecatheter).
AftergeometricalreconstructionoftheRV,pace-mappingof
threesiteswasperformed(Figure1):
para-Hissian(about1cm
intotheventriclefromtheHis),themid-septum(atthecentre
oftheseptumintherightobliqueanteriorview,roughlyhalfway
alongthelinedrawnbetweentheHisandtheapex,andcaudal
totheleveloftheHis),andtheRVanteriorfreewall(closeto
theanteroseptalsulcus,wherepacingleadsareofteninadvertently
placed).Anatomicaltaggingwasperformedateachsiteandthe
ventriclewaspacedat80bpmfor10–20capturedbeats,during
whicha12-leaddigitalECGwascontinuouslyrecordedusingthe
Bard
electrophysiologybay(Figure2).
Electrocardiogramanalysis
The12-leadECGderivedfromeachpacingsitewasanalysed
off-lineusingthedigitalcallipersoftheBard
electrophysiology
bay.Thefollowingparameterswereanalysed:
(1)QRSduration
(2)AmplitudesofQ,R,andSwavesinalllimbleads.ThenetQRS
amplitudeineachleadwascalculatedasR2(Q+S),andwas
usedtodefinewhethertheQRSwaspositiveornegativein
thatlead,andforcalculationoftheQRSaxis.
(3)QRSaxiscalculatedusingnetQRSamplitudesinleadsIand
aVFwiththefollowingformulathatweconceived:
axis¼
57.3*ATAN(AVF/I).Thevaluewasmanuallyadjustedfor
axesof+908or2908incaseofaperfectlyisoelectricQRS
complexinleadI(astheformulayieldsanerrorforleadI¼
0),andcorrectedbyadding1808totheresultiftheQRS
wasnegativeinleadI.AvisuallyestimatedQRSaxiswasalso
notedtoserveasacontrol.
(4)Presenceofaq-waveoranegativeQRSinleadI(whichhas
previouslybeenattributedtoseptalpacing
9,12
)
(5)PresenceofQRSnotchinginthelimbleads(pacingoffreewall
siteshasbeenreportedtoresultinnotchingintheinferior
leads
(6)QRStransitionintheprecordialleads(atransitionatorlater
thanV4hasbeenshowntodistinguishRVOTfreewallsites
fromanRVOTseptalsite
12
).Transitionwasdefinedasthe
leadwithR.(Q+S)amplitude.
Themeasurementswereperformedbyasingleobserver(C.-I.P.)
andverifiedbyasecondinvestigator(H.B.).
................................................................................
Table1Patientsdemographics
Allpatients(n531)
Age(years)70+11
Male/Female26/5
Underlyingheartdisease
Ischaemic9
Dil
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