内科学 心律失常朱文青

ArrhythmiaZhuwen--qingDep.OfCardiology,Zhong--ShanHospital,FuDanUniversity.Shanghai.China.1Conductionandanatomyofheart2Conductionsystem3StableSVTisgenerallywelltoleratedinpatientswithoutunderlyingheartdisease!!!!!???butmayleadtomyocardialischemiaorcongestiveheartfailureinpatientswithcoronarydisease,valvularabnormalities,andsystolicordiastolicmyocardialdysfunction.

Ventriculartachycardia,iflasting>10~30secs,oftenresultsinhemodynamiccompromiseandismorelikelytodeteriorateintoventricularfibrillation.RATE&RHYTHM4RATE&RHYTHMslowheartratesproducesymptomsatrestoronexertiondependsuponwhethercerebralperfusioncanbemaintained,whichisgenerallyafunctionofwhetherthepatientisuprightorsupineandwhetherleftventricularfunctionisadequatetomaintainstrokevolume.Iftheheartrateabruptlyslows,aswiththeonsetofcompleteheartblockorsinusarrest,syncopeorconvulsionsmayresult.

5RATE&RHYTHMArrhythmiasaredetectedeitherbecausetheypresentwithsymptomsordetectedduringthecourseofmonitoring.Arrhythmiascausingsuddendeath,syncope,ornearsyncoperequirefurtherevaluationandtreatmentunlesstheyunlikelytorecur(eg,electrolyteabnormalitiesoracutemyocardialinfarction).Controversyoverwhenandhowtoevaluateandtreatrhythmdisturbancesthatarenotsymptomaticbutarepossiblemarkersformoreseriousabnormalities(eg,nonsustainedventriculartachycardia).6MECHANISMSOFARRHYTHMIASElectrophysiologicstudies

havegreatlyincreasedourunderstandingofthemechanismsunderlyingmostarrhythmias.Theseinclude(1)disordersofimpulseformationorautomaticity(2)abnormalitiesofimpulseconduction,(3)reentry,and(4)

triggeredactivity.Alteredautomaticityisthemechanismforsinusnodearrest,manyprematurebeats,andautomaticrhythmsaswellasaninitiatingfactorinreentry,arrhythmias.7MECHANISMSOFARRHYTHMIASAbnormalitiesofimpulseconductioncanoccuratthesinusoratrioventricularnode,intheintraventricularconductionsystem,andwithintheatriaorventricles.Theseareresponsibleforsinoatrialexitblock,foratrioventricularblockatthenodeorbelow,andforestablishingreentrycircuits.8MECHANISMSOFARRHYTHMIAS9MECHANISMSOFARRHYTHMIAS

Triggeredactivityoccurswhenafterdepolarizations(abnormalelectricalactivitypersistingafterrepelarization)reachthethresholdlevelrequiredtotriggeranewdepolarization.ThismaybethemechanismofventriculartachycardiaintheprolongedQTsyndromeandinsomecasesofdigitalistoxicity.

10TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCESElectrocardiographicMonitoringTheidealwayofestablishin,gacausalrelationshipbetweenasymptomandarhythmdisturbanceistodemonstratethepresenceoftherhythmduringthesymptom,Unfortunately,thisisnotalwayseasybecausesymptomsareusuallysporadic.11TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCESElectrocardiographicMonitoringPatientswithSDandrecentorrecurrentsyncopeareoftenmonitoredinthehospital.Outpatients.Whenepisodesareinfrequent,useofaneventrecorderispreferableto24-hourcontinuousmonitoring.Exercisetestingmaybehelpfulwhenthesymptomsareassociatedwithexertionorstress.Furtherelectrophysielogicstudiesmaybeusefulinevaluatingventriculartachyarrhythmias.

12TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCESElectrocardiographicMonitoring13ElectrocardiographicMonitoring14ElectrocardiographicMonitoring15TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCESECGMonitoringInmanycases,symptomsareduetoadifferentarrhythmiaortononcardiaccauses.Forinstance,dizzinessorsyncopeinolderpatientsmaybeunrelatedtoconcomitantlyobservedbradycardia,sinusnodeabnormalities,andventricularectopy.Ambulatorymonitoringisfrequentlyusedtoquantifyventricularectopyanddetectasymptomaticventriculartachycardiainpost-myocardialinfarctionorheartfailurepatients.Unfortunately,whileasymptomaticventriculararrhythmiashavenegativeprognosticimplications,therearefew-datatosupportspecifictherapeuticintervention.Thus,monitoringinasymptomaticindividualsisusuallynotindicated.

16TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCESHeartrateVariablityseveralstudieshaveindicatedthatgreaterheartratevariabilityisassocialedwithabetterprognosisandfewerlifethreateningarrhythmiasinavarietyofcardiacconditions.RRcyclelengthvariabilitytoprovideindicesoftherelativebalancebetweenparasympatheticandsympatheticactivity,withbeingconsideredtoconferabetterprognosis.postinfarctionandpatientswithsymptomaticarrhythmias,theseIndiceshavehadsomeprognosticvalue.However,adequatedataarenotyetavailabletosupportroutineuseofthistechniqueinclinicalpractice.

17TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCESSignal-AveragedECGSignalaveragedECGisnewtechnique.Torecord300consecutivebeatsduringbasalconditions,Usingappropriateelectricalfilteringandcomputeraveragingofthesignal,verylawfrequencysignalscalled"latepotentials"canbeidentifiedintheperiodfollowingtheQRScomplex.AbnormallatepotentialsareconsideredmarkersforpotentialVentricularArrhythmia18TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCES

ElectrophysiologyTestEvaluationofrecurrentsyncopeofpossiblecardiacorigin,whentheambulatoryECGhasnotprovidedthediagnosis;DifferentiationofSVTfromVA;Evaluationoftherapyinpatientswithaccessoryatrioventricularpathways;EvaluationoftheefficacyofpharmacotherapyinsurvivorsofsuddendeathorotherpatientswithsymptomaticorlifethreateningVT;Evaluationofpatientsforcatheterablationproceduresorantitachycardiadevices.19AutonomicTesting(TiltTableTesting)withrecurrentsyncopeornearSyncope,arrhythmiasarenocause.Thisisparticularlytruewhenthepatienthasnoevidenceofassociatedheartdiseasebyhistory,examination,ECG,ornoninvasivetesting.Syncopemaybeneurocardiogenicinorigin,mediatedbyexcessivevagalstimulationoranimbalancebetweensympatheticandparasympatheticautonomicactivity.

TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCES20TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCESAutonomicTesting(TiltTableTesting)60°-80°21TECHNIQUESFOREVALUATINGRHYTHMDISTURBANCES22AntiarrhythmiadrugAntiarrhythmicdrugshavelimitedefficacyandfrequentsideeffects.Theyareoftendividedintofourclasses.ClassIagentsblockmembranesodiumchannels.ThreesubclassesarefurtherdefinedbytheeffectofagentsonthePurkinjefiberactionpotentialClassladrugsslowtherateofriseoftheactionpotential(Vmax)andprolongitsduration,thusslowingconductionandincreasingrefractorineas.Classlbagentsshortenactionpotentialduration',theydonotaffectconductionorrefractoriness.ClassIcagentsprolongVmaxandslowrepolarization,thusslowingconductionandprolongingrefractoriness,butmoresothanclassladrugs23AntiarrhythmiadrugClassIIagents---beta-blockersDecreaseautomaticity,ProlongAVconduction,Prolongrefractoriness.24AntiarrhythmiadrugClassIIIagentsBlockpotassiumchannelsProlongrepolarization,wideningtheQRSandprolongingtheQTinterval.Decreaseautomaticityandconductionandprolongrefractoriness.25AntiarrhythmiadrugClassIVagents

----slowcalciumchannelblockers

DecreaseautomaticityandAtrioventricularconduction26Drugs27Antiarrhythmiadrug--RiskTheriskofantiarrhythmicagentshasbeenhighlightedbytheCoronaryArrhythmiaSuppressionTrial(CAST).TwoclassIcagents(flecainide,encairfide)andaclamlaagent(moficizine)increasedmortalityratesinpatientswithasymptonlaticventricularectapyaftermyocardialinfarction.Therefore,theseagents(anyantiarrhythmicdrug)shouldnotbeusedexceptforlife-threateningventriculararrhythmiasandsymptomaticsupraventriculartachyarrhythmias.28RadiofrequencyAblationAblationhasbecometheprimarymodalityoftherapyformanysymptomaticSVTIncludingAVNRTAVRT-----involvingaccessorypathways,paroxysmalatrialtachycardia,

inappropriatesinustachycardia,

junctionaltachycardia,Manylaboratorieshaveachievedreasonablesuccessratesinpreventingatrialflutterwithrediofrequencytechniques,andexperiencewithatrialfibrillationisaccumlatingaswell.29RadiofrequencyAblationCatheterablationofVAhasprovedmoredifficult.ThreespecilicformsofVAprovedtobeamenabletoradiofrequeneyablation.bundlebranchreentry,VToriginatinginrightventricuiaroutflowtract,VToriginatingintheleftsideoftheinterventricularseptum.OtherformsofVT,maybeamenabletoablation,butexperiencethusfarislimited.30RadiofrequencyAblationInaddition,someproceduresinvolvetransseptalorretrogradeleftventricularcatheterization,withtheattendantpotentialcomplicationsofaorticperforation,damagetotheheartvalves,orleft-sidedemboli.Theseproceduresaregenerallysafe,thoughthereisalowincidenceofperforationoftheatriaorrightventriclethatresultsinpericardialtamponadeandsufficientdamagetotheatriovantricularnodetorequirepermanentcardiacpacing.31323334AVRTablation3536AVNRTAblation37Atrialtachycardia--ablation38Atrialfibrillationaccountsfor1/3ofallpatientdischarges

witharrhythmiaas

principaldiagnosis.

2%VF

Datasource:BailyD.JAmCollCardiol.1992;19(3):41A.34%

Atrial

Fibrillation18%

Unspecified6%

PSVT6%

PVCs4%

Atrial

Flutter9%SSS8%

Conduction

Disease3%SCD10%VT39SUPRAVENTRICULAR

ARRHYTHMIAS—sinusbradycardiaCausesofSlowRhythms:HypoxiaHyperkalemiaAcuteMIHeartDiseaseIncreasedparasympathetictoneDrugeffectsfromnarcotics,benzodiazepines,digoxin,betablockers,propranolol,orcalciumchannelblockers40SinusBradycardiaDecreaseintherateofatrialdepolarizationRhythmisregularRate<60PwavesuniformandoneinfrontofeachQRScomplexPRintervalandQRScomplexisnormal41SinusBradycardiaseveresinusbradycardiamaybeanindicationofsinusnodepathologyespeciallyinelderlypatientsandindividualswithheartdisease.Itmaycauseweakness,confusion,orsyncopeifcerebralperfusionisimpaired.Atrialandventricularectopicrhythmsaremoreapttooccurwithslowsinusrates.Pacingmayberequiredifsymptomscorrelatewiththebradycardia.42SinusBradycardiaTreatment:Ifaccompaniedbyhypotension,syncopeorlightheadedness:StopprocedureAtropineIVTranscutaneouspacingdopamine,epinephrineandtransvenouspacemaker43FastRhythms:

SinusTachycardiaandSupraventricularTachycardiaCauses:HypoxiaEmotionalandphysicalstresscaffeine,smokingexercisefatiguealcoholpaininfectioncardiomyopathy44SinusTachycardia

Sinusnodeisstillthepacemaker,buttherateisacceleratedRhythmisregularRate>100beats/minPwave,PRinterval,andQRScomplexareallnormal45SinusTachycardiaTreatment:Alleviatetheunderlyingcause"inappropriate"sinustachycardiathatmaybeverysymptomaticorleadtoLVcontractiledysfunction.

Radiofrequeneymodificationofthesinusnodehasmitigatedthisproblem

46ATRIALPREMATUREBEATSAPBoccurbeforethenextsinusnodeimpulseorareentry_circuitisestablished.Pwaveusuallydiffersfromthepatient'snormal.R-Rcyclelengthisusuallyunchangedoronlyslightlyprolonged.prematurebeatsoccurinnormalheartsandareneverasufficientbasisheartdisease.Speedingoftheheartratebyanymeansusuallyabolishesmostprematurebeats.EarlyAPBmaycauseaberrantQRScomplexesormaybenonconductedtotheventriclesbecausethelatterarestillrefractory.

47VariabilityofVentricularEctopywithAgeEffectofageonprobability(%)ofhavingmorethanagivennumberof

PVCsper24hoursinsubjectswithnormalhearts.10-2930-3940-4950-5960-69DatafromKostisJB.Circulation.1981;63(6):1353.Age48VENTRICULARBEATSDistinctioncanbeverydifficultinpatientswithawideQRS;itisimportantbecauseofthedifferingprognosticandtherapeuticimplicationsofeachtype.ventricularorigininclude

atrioventriculardissociation;aQRSdurationexceeding0.14s;captureorfusionbeats(infrequent);leftaxisdeviatinnwithrightbundlebranchblockmorphology;monophasic(R)orbiphasic(qR,QR.,orRS)complexesinV1,;and(6)aqRorQScomplexinV6.49VENTRICULARBEATSSupraventricularoriginisfavoreclbyatriphasicQRScomplex,especiallyiftherewasinitialnegativityinleadsIandV6;ventricularratesexcceeding170/min;QRSdurationlongerthan0.12sbutnotlongerthan0.14s:thepresenceofpreexcitationsyndrome.50Asingleirritablefocuswithintheventriclefiresprematurelygivingrisetoanectopicbeat.QRSiswideIfeveryotherbeatisPVCventricularbigeminyIfeverythirdbeatisaPVCventriculartrigeminyIfeveryfourthbeatisPVCventricularquadrigeminyAPVCthatfallsontheTwaveprecipitatesVTorVFVENTRICULARBEATS51VENTRICULARBEATSTreatment:PVC’swhichneedtobetreatedare:MultifocalOccurincoupletsFallonoraftertheTwaveThatoccurgreaterthan6perminute52PrematureVentricularContraction

TreatmentContinued:InthesettingofanacuteMI,PVC’sneedtobeaggressivelytreatedwithnitroglycerine,aspirin,morphineandoxygen.LidocaineisthedrugofchoicetodiminishPVC’s,butdoeslittletotheunderlyingpathology.

53SUPRAVENTRICULARTACHYCARDIA

thecommonest

paroxysmaltachycardiaandoftenoccursinpatientswithoutstructuralheartdisease.Attacksbeginandendabruptlyandmaylastafew,secondstoseveralhoursorlonger.Hrmaybe140-240/mia(usually160-220/min)andisperfectlyregular(despiteexerciseorchangeinposition).Pwaveusuallydiffersincontourfromshinsbeats.Asymptomatic,butsomeexperiencemildchestpainorshormessofbreath,especiallywhenepisodesareprolonged,evenintheabsenceofassociatedcardiacabnormalities.PSVTmayresultfromdigitalistoxicityandtheniscommonlyassociatedwithatrioventricularblock.54SVT55SVT56SVT--CareAMechanicalMeasures:Avarietyofmethodshavebeenusedtointerruptattacks,andpatientsmaylearntoperformthesethemselves.TheseincludeValsalva'smaneuver,stretchingthearmsandbody,loweringtheheadbetweentheknees,coughing,andbreathholding.57SVT--treatmentB.DrugTherapy:Iffail,rapidlyintravenousagentswillterminatemorethan90%ofepisodes,

Intravenousadenosine(orATP)hasaverybriefdurationofactionandminimalnegativeinotropieactivity,A6-mgbolusisadministered.Ifnoresponseisobservedafter10minutes,asecondandthird12-mgbolusshodldbegiven.Sincethehalf-lifeofadenosineislessthan10seconds,drugmustbegivenrapidly(in12secondsfromaperipheralintravenousline).Adenosineisverywelltolerated,butnearly20%--flushing,andsomepatientsexperienceseverechestdiscomfort.

58SVT—Care

CalciumchannelblockersalsorapidlyinduceatrioventricularblockandbreakmostepisodesofreentrySVT.IVverapamilmaybegivenasa2.5mg-bolus,followedbyadditionaldosesof2.5to5mgevery1--3minutesuptoatotalof20mgifbloodpressureandrhythmarestable.Iftherecurs,furtherdosescanbegiven59SVT--Care

Cardioversion:Ifthepatientishemodynamicallystableorifadenosineandvempamilarecontraindicatedorineffective,synchronizedelectricalcardioversion(beginningat100J)isalmostuniversallysuccessful.

Ifdigitalistoxicityispresentorstronglysuspected,asinthecaseofparoxysmaltachycardiawithblock.electricalcardioversionshouldbeavoided.60PreventionofAttacksA.RadiofrsquencyAblation:SafetyandLessrecurrentB.Drugs:Verapamil、

Propafenone

、

Amiodarone61PreexcitationSyndromes

Wolff-ParkinsonWhitesyndrome.

Directconnectionsbetweentheatriaandventricle(Kentbundles);Lown-Ganong-Levinesyndrome:

shortPRintervalandnormalQRSmorphology

Mahaimfibers:whollyorpartlywithinthenode

62PreexcitationSyndromes63AVRT--WPWPathwaysoccurin0.1-0.3%.20-30%ofpatientswithtachyarrhythmiashaveatrialfibrillationorflutter

!!!PatientswithRRintervalslessthan220msareathighestrisk.DigoxinSayNO!verapamilandbetablockersmaydecreaseAPrefractorinessandincreaseventricularresponseandshouldbeavoidedinatrialfibrillationwithaccessorypathwaysTreatment.64WPW65AVRT—WPWCareRadiofrequencycatheterablation;PharmacologicTherapy.66Atrialfibrillation

Atrialfibrillationisthecommonestchronicarrhythmia.Itoccursinrheumaticheartdisease,dilatedcardiomyopatliy,ASD,hypertension,mitralvalveprolapse,andhypertrophiccardiomyopathyaswellasinpatientswithnoapparentcardiacdisease.itmaybetheinitialpresentingsigninthyrotoxicosis.Atrialfibrillationoftenappearsparoxysmallybeforebecomingtheestablishedrhythm.6768AtrialfibrillationAtrialrateis350-600/min,butmostimpulsesareblockedattheatrioventricularnode.

Diagnosis:ECG69AtrialfibrillationAcutemanagementearlycardieversion-24~48hsayNoOradequatelyanticoagulatedfor3-4weeksIVbeta-blockersorverapamilordiltiazem,digoxin,oracombinationoftheseapproaches.70AtrialfibrillationTreatmentofChronicAtrialFibrillationTheproblemsposedbychronicAfareprimarilytwo:symptomsrelatedtothearrhythmiasandtheincreasedriskofthromhoemboliephenomena.

Drug:anticoagulationorcontrolHr

Ablation:pacemakeretc.Surgeon71AtrialFlutterAFislesscommonthanfibrillation.COPDorwithrheumaticorCHD,CHF,ASD,orsurgicallyrepairedcongenitalheartdisease.Atrialratesof250-350/rain,withtransmissionofevery2:1/3:1/4:1atrioventricularnodetotheventricles.72ATRIALFLUTTERChronicatrialflutterisoftenadifficultmanagementproblem,ratecontrolisdifficult.Drug:anticoagulationorcontrolHr

Ablation:pacemakeretc.Surgeon73ATRIALFLUTTER74DiagramofAtrialFlutterCircuitWithinRightAtriumCosioFG.AmJCardiol.1993;71:705-709.Inferiorvenacava-

tricuspidvalveisthmus75ATRIALTACHYCARDIA

ThisisarhythmcharacterizedbyvaryingP-wavemorphology(bydefinition,threeororefoci)andmarkedlyirregularPPintervals.Therateisusuallybetween100and140/min,andatrieventricularblockisunusualMostpatientshavesevereassociatedCOPD.Treatmentoftheunderlyingconditionisthemosteffectiveapproach;verapamil,240-480mgdailyindivideddoses,isalsoofvalueinsamepatients.76ATRIALTACHYCARDIA77ATRIALTACHYCARDIA78ATRIOVENTRICULARTIONALRHYTHMTheatrial-nodaljunctionorthenodal-Hisbundlejunctionsmayassumepacemakeractivityfortheheart,usuallyatarateof4060/min.Patientswithmyocarditis,CHD,anddigitalistoxicityaswellasinindividualswithnormalhearts.Diagnosis:ECG/monitoring,butitcanbesuspectedifIhejugularvenouspulseshowscannonawaves.NonparoxysmaljunctionaltachyeardiaresultsfromdigitalistoxicityorischemiaandisassociatedwithanarrowQRScomplexandarateusuallylessthan120-130/min.Consideredbenignwhenitoccursinacutemyocardialinfarction,buttheischemiamayalsocauseVTandVf.79VENTRICULARARRHYTHMIAS----ENTRICULARPREMATUREBEAT

VentricularPrematurebeatsarecharacterizedbywideQRScomplexesthatdifferinmorphologyfromthepatient'snormalbeats.TheyareusuallynotprecededbyaPwave,althoughretrogradeventriculoatrialConductionmayoccur.80VENTRICULARARRHYTHMIAS

----VENTRICULARPREMATUREBEAT81VENTRICULARARRHYTHMIAS

----VENTRICULARPREMATUREBEATDiagnosis:ECG/Ambulatorymonitoring

Treatment:Drugs/AblationIfnoassociatedcardiacdiseaseispresentandasymptomatic,notherapyisindicated.mayexacerbateseriousarrhythmiasin5~20%ofpatients.Therefore,toavoidusingclassIorIIIantiarrhythmicagentsinpatientswithoutsymptoms.82VENTRICULARARRHYTHMIAS

----VENTRICULARTACHYCARDIA

VTisdefinedasthreeormoreconsecutiveventricularprematurebeats.Theusualrateis160-140/mmandismoderatelyregularbutlesssothanatrialtachycardia.Diagnosis:ECG/Monitor/EPS83VENTRICULARARRHYTHMIAS----VTVTcauseshypotension,heartfailure,ormyocardialischemia,synchronizedDCcardioversionwith100-360Jshouldbeperformedimmediately.PatientisstableIVlidocaine/procainamide/amiodarone.VTaimbeterminatedandPreventrecurrent.84Ventriculartachycardia85VENTRICULARARRHYTHMIAS----VTSustainedVTDrugsAblationAICDSurgeon86VENTRICULARARRHYTHMIAS----VTNonsustainedVT(NSVT)definedasrunsofthreeormorebeatslastinglessthan30seconds.ICDwillimproveprognosis.Betterprognosissuggeststha