Utility of the surface electrocardiogram for.docx

Utility of the surface electrocardiogram for.docx

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Utilityofthesurfaceelectrocardiogramfor

Utilityofthesurfaceelectrocardiogramfor

confirmingrightventricularseptalpacing:

validationusingelectroanatomicalmapping

HaranBurri

1

*,Chan-ilPark

1

MarcZimmermann

2

PascaleGentil-Baron

1

CarineStettler

1

HenriSunthorn

1

GiuliaDomenichini

1

andDipenShah

1

1

CardiologyService,UniversityHospital,4,rueGabrielle-Perret-Gentil,1211Geneva14,Switzerland;and

2

CardiologyService,LaTourHospital,Geneva,Switzerland

Received27June2010;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,P¼0.028）andanterior（53+558,P¼0.003）pacing,andQRStransitionwasintermediate

（4.8+1.3vs.3.8+1.3,P,0.001,andvs.5.4+0.9,P¼0.045,respectively）,althoughnocut-offscouldreliablydistinguishsites.AnegativeQRSorthepresenceofaq-waveinleadItendedtobemorefrequentwithanteriorthan

withmid-septalpacing（9/31vs.3/31,P¼0.2and8/31vs.1/31,P¼1.0,respectively）.

ConclusionNosingleECGcriterioncouldreliablydistinguishpacingthemid-septumfromtheanteriorwall.Inparticular,anegativeQRScomplexinleadIisaninaccuratecriterionforvalidatingseptalpacing.

-----------------------------------------------------------------------------------------------------------------------------------------------------------

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

6

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

w

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

w

electrophysiologybay（Figure2）.

Electrocardiogramanalysis

The12-leadECGderivedfromeachpacingsitewasanalysed

off-lineusingthedigitalcallipersoftheBard

w

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

9,12

）

（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