室上性心动过速相关的X线影像和解剖D1

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Figure1.33showsthecatheterpositions(RAOandLAOviews)ina72-year-oldmanwhohadimplantationofapermanentdual-chamberpacemakerafterAVnodalablation.Thepatienthasahistoryofrecurrentorthodromicreciprocatingtachycardia.HisablationwasperformedintheeraofDCablation,anddeterminatetachycardiaandhisAVnodewereablated,Sincehispathwayshowedbothantegradeandretrogradeconduction,theECGstillshowedpreexcitationduringatrialpacingorsinusrhythm.HewasreferredtotheEPlaboratoryforEPstudyandradiofrequencyablationoftheaccessorypathway(approximately18yearsafterDCablation).WhywouldapatientrequireablationofanaccessorypathwayevenaftertheAVnodehasbeenablatedsuccessfully?

Recurrentorthodromicreciprocatingtachycardia

Recurrentantidromicreciprocatingtachycardia

Preexcitedatrialfibrillation

Reccrrentpacemaker-mediatertachycardia

AandB

CandD

Answer:F-CandD.

图1.33为1例72岁男性患者的RAO与LAO

影像。该患者曾接受房室结消融及永久性双腔起搏器植入治疗。既往有顺向型房室折返性心动过速(AVRT)的反复发作病史。其消融完成于直流电消融时代（eraofDCablation),心动过速在某种程度上得到了有效治疗。由于旁路有前传与逆传功能，心房起搏或窦性心律时心电图仍显示预激波。患者在直流电消融大约18年后再次入院，拟行电生理检查及旁路的射频消融。问题：既然患者已经接受了成功的房室结消融，为什么还要对旁路进行消融？

A.顺向型AVRT反复发作

B.逆向型AVRT反复发作

C.预激综合征合并心房颤动

D.起搏器介导性心动过速反复发作

E.A和B

F.C和D

结论：F-C和D

WiththeAVnodeablated,reciprocatingtachycardia(eitherantidromicorthodromic)isnolongerpossible.Ofcourse,ifanotheraccessorypathwayispresent,apathway-topathwaytachycardiacanstilloccur,butnotreciprocatingtachycardiainvolvingtheAVnode.Aspatientsgetolder,thechanceofatrialfibrillationunrelatedtotheaccessorypathwayincreases.Sincetheaccessorypathwaystillcanconductantegrade,preexcitedatrialfibrillation,apotentiallymalignantarrhythmia,isstillpossibleafterAVmodalablation.Althoughthispatientdidhaveatrialfibrillationwithsomepreexcitation,themainreasonforhisreferraltotheEPlaboratorywasrecurrentpacemakersyndrome.Inpacemakersyndrome,retrogradeatrialelectrogrambythepacemakerleadintheatrium,triggeringapacedA-Vintervalandventricularpacing.Thisventricularpacedbeatagaingivesrisetoretrogradeconduction,andtheprocessrebeatsitself.UsuallythispatternofreciprocatingactivationoccursbecauseofretrogradeconductionviatheAVnode,andprogrammingapostventricularatrialrefractoryperiodlongerthantheretrogradeconductiontimepreventsthisarrhythmiafromoccurring.Thispatienthadaverylongretrogradeconductiontimethroughapoorlyconductionretrogradepathway.Thus,thepostventricularatrialrefractoryperiodcouldnotbeprolongedenoughtopreventrecurrent,incessantpacemaker-mediatedtachycardia.

由于房室结已被成功消融，患者不可能再发生顺向型或逆向型AVRT。当然，如果还有一条旁路，两条旁路之间可以形成折返，引起心动过速，但它并不是房室结参与的折返性心动过速。随着年龄的增长，患者出现与旁路无关的心房颤动的概率也将增大。因旁路仍有前传功能，患者在房室结消融之后亦有可能发生预激综合征合并心房颤动，这是一种潜在的恶性心律失常。尽管患者曾出现过预激综合征合并心房颤动，但此次入院行电生理检查的主要原因是反复发作的起搏器综合征（pacemakersyndrome)。对于起搏器综合征患者来说，当心房起搏电极感知到室房逆传引起的心房激动后，按照预设的AV间期触发心室激动，后者再次引发室房逆传，如此反复即导致起搏器介导性心动过速（pacemaker-mediatedtachycardia)。通常情况下，这种折返性心动过速的逆传经由房室结，只需程控心室后心房不应期(postventricularatrialrefractoryperiod),使其超过心动过速的逆向传导时间，就可预防发作。但该患者旁路的逆向传导功能较差，其逆向传导时间非常长，尽管延长心室后心房不应期也不足以预防这种无休止性起搏器介导性心动过速的发作。

Hewasthusreferredforradiofrequencyablationusinga20-electordemultipolarcatheterplacedalongthetricuspidannulus(Figure1.33,whitearrows)andanablationcatheterusedformappingalongtheposterolateraltricuspidannularlocations.

患者因此入院行射频消融术。术中沿三尖瓣环放置1根20极标测导管（图1.33中白箭头所示）,消融导管则置于三尖瓣环后侧壁进行标测。

orthodromicreciprocatingtachycardia顺向型AVRTpreexcitation预激malignantarrhythmia恶性心律失常

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