Andersons pediatric cardiology 569
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (130.74 KB, 3 trang )
inhibitionofabnormalautomaticityandincreaseintherefractoryperiodofthe
AVnodeandHis-Purkinjesystem.Hence,amiodaronehasbeenreportedtobe
oneofthemosteffectiveagentsinmanagingJETaftercardiacsurgeryin
general.94,211,212Inarecentstudy,thepreemptiveuseofdexmedetomidineand
intravenousamiodaroneintheperioperativeperiodwasassociatedwitha
significantlydecreasedincidenceofJETascomparedwithplaceboandwithout
significantsideeffects.
IftheJETrateisslow,pacingalonetoachieveAVsynchronymaybe
adequatetoimprovethehemodynamics.Attimescoolingandpharmacologic
therapymaybeneededtoslowtherateinorderforpacingtobepossibleand
effective.PacingusinganAAImodeispreferableasthisallowsfornormalAV
conductionandlessdyssynchronythanDDDpacing.
CompleteHeartBlock(Postsurgical)
Theincidenceofcompleteheartblockfollowingcongenitalheartsurgeryis
about1.4%to1.9%andisgenerallytheconsequenceofsurgeryinvolving
closureofaventricularseptaldefectorsurgeryinthevicinityoftheaortic
valve.34,87,213
Surgicalpostoperativeheartblocktendstooccurimmediatelyaftersurgeryor
intheveryearlypostoperativeperiod(Fig.22.41).Earlypostoperativeheart
blockcanbetransient,withareturntonormalsinusrhythmandnormalAV
conduction,oritmayremainapermanent.Ifpatientsaregoingtorecover
followingsurgery,recoverywilloccurbypostoperativeday9in97%ofpatients
withtransientheartblock.33Temporaryepicardialpacing,preferablyinanatrial
sensed-ventricularpacedmode,shouldbeutilizedwhileawaitingresolutionof
AVconduction,especiallyiftheunderlyingrateisslow,widecomplex,pauseinducedventricularectopyorthecardiacoutputispoor.Useoftemporary
epicardialpacingandmanipulationsoflowerrates,AVintervals,PVARP,upper
rateshouldalwaysbedonecarefullyandjudiciouslywhilepayingclose
attentiontotheinvasiveandnoninvasivemonitors.Resolutionofpostoperative
AVblocktothatofresidualtrifascicularblock(RBBB,leftaxisdeviation,and
first-degreeAVblock)hasbeendiscussedanddebatedforyears.202
AntiarrhythmicmedicationsthatcauseAVblockshouldbeavoidedinpatients
withtrifascicularblock.214Inpatientswhosepostoperativeheartblockaftera
periodof7to10daysrevertstosinusrhythmonlywithRBBBandleftaxis
deviationthereisaclassIIBindicationforapermanentpacemaker.However,at
alltimesdecisionsregardingpermanentpacingshouldincludeanunderstanding
ofthepatient'ssymptoms,especiallyiftheratesareslow,aswellasthe
underlyinghemodynamics.UseoftemporarywirestoassessAVnodal
conductionmaybevaluableinthepostoperativeperiodiftherewasconcern
abouttherobustnessoftheAVnode.Inpatients,withtransientpostoperativeAV
blockwhoserecoveryisnotcompletelybacktosinusrhythmandwhohappento
begoingforadiagnosticcatheterization,itmaybeofbenefittomeasureandAH
andHVinterval.Patientswith2:1AVblockpostsurgerywithaprolongedHV
intervalareamoreconcerningsubcohort.
FIG.22.41 Postoperativemanagementalgorithmforjunctionalectopic
tachycardia(JET).ECMO,Extracorporealmembraneoxygenation;IV,
intravenous.
SupraventricularTachycardia
SVTmaycomplicatethemanagementofchildrenafterheartsurgery.This
