资源描述
An Electrophysiologic OverviewVentricular TachyarrhythmiasAn Electrophysiologic OverviewModule Objectives Ventricular TachyarrhythmiasIdentify the mechanisms for ventricular tachycardiasDifferentiate types of ventricular tachycardias using ECG and intracardiac electrogram recordingsDiscuss treatment options for ventricular tachycardiasAfter completion of this module,the participant should be able to:Module Objectives VentriculModule Outline Ventricular TachyarrhythmiasI.DescriptionII.CharacteristicsA.MechanismsB.Sustained vs.nonsustainedC.Premature ventricular contractionsModule Outline Ventricular Module Outline Ventricular TachyarrhythmiasIII.ClassificationA.Monomorphic1.Idiopathica.Descriptionb.ECG recognitionc.Treatment ablation2.Bundle brancha.Descriptionb.ECG recognitionc.Treatment ablationModule Outline Ventricular Module Outline Ventricular TachyarrhythmiasIII.Classifications-continued3.Ventricular fluttera.ECG recognition4.Ventricular fibrillationa.ECG recognitionB.Polymorphic1.Torsades de pointesa.Descriptionb.ECG recognitionc.TreatmentIV.SummaryModule Outline Ventricular Ventricular Tachycardia(VT)Originates in the ventricles Can be life threateningMost patients have significant heart diseaseCoronary artery diseaseA previous myocardial infarctionCardiomyopathyVentricular Tachycardia(VT)OrMechanisms of VTReentrant Reentry circuit(fast and slow pathway)is confined to the ventricles and/or bundle branchesAutomatic Automatic focus occurs within the ventriclesTriggered activityEarly afterdepolarizations(phase 3)Delayed afterdepolarizations(phase 4)Mechanisms of VTReentrant ReentrantReentrant ventricular arrhythmiasPremature ventricular complexesIdiopathic left ventricular tachycardiaBundle branch reentryVentricular tachycardia and fibrillation when associated with chronic heart disease:Previous myocardial infarctionCardiomyopathyReentrantReentrant ventricularAutomaticAutomatic ventricular arrhythmiasPremature ventricular complexesIschemic ventricular tachycardiaVentricular tachycardia and fibrillation when associated with acute medical conditions:Acute myocardial infarction or ischemiaElectrolyte and acid-base disturbances,hypoxemiaIncreased sympathetic toneAutomaticAutomatic ventricularAutomaticityAbnormal Acceleration of Phase 4Fogoros:Electrophysiologic Testing.3rd ed.Blackwell Scientific 1999;16.AutomaticityAbnormal AcceleratTriggeredTriggered activity ventricular arrhythmiasPause-dependent triggered activityEarly afterdepolarization(phase 3)Polymorphic ventricular tachycardiaCatechol-dependent triggered activityLate afterdepolarizations(phase 4)Idiopathic right ventricular tachycardiaTriggeredTriggered activity veTriggeredFogoros:Electrophysiologic Testing.3rd ed.Blackwell Scientific 1999;158.TriggeredFogoros:ElectrophysECG recognitionIdiopathic Right Ventricular TachycardiaRhythm:Regular and uniformIncreased sympathetic toneMonomorphic VTCardioversionElectrolyte abnormalitiesCharacteristicsOriginates in the ventriclesPolymorphic ventricular tachycardiaSuccess largely depends on the etiology of the arrhythmiaBundle branch reentrySustained VTSustained VTIf the heart is paced from this region,the resulting ECG should be identical to the ECG taken during tachycardiaStable and uniform beat-to-beat appearanceRhythm:IrregularPause-dependent triggered activitySustained vs.NonsustainedSustained VTEpisodes last at least 30 secondsCommonly seen in adults with prior:Myocardial infarctionChronic coronary artery diseaseDilated cardiomyopathy Non-sustained VTEpisodes last at least 6 beats but 30 secondsECG recognitionSustained vs.NPremature Ventricular ContractionPVCEctopic beat in the ventricle that can occur singly or in clustersCaused by electrical irritabilityFactors influencing electrical irritabilityIschemiaElectrolyte imbalancesDrug intoxicationPremature Ventricular ContractClassificationVentricular TachycardiaMonomorphicIdiopathic VT Bundle branch reentry tachycardiaVentricular flutterVentricular fibrillationPolymorphicTorsades de pointes(TdP)ClassificationVentricular TachMonomorphic VTsMonomorphic VTsMonomorphic VTHeart rate:100 bpm or greaterRhythm:RegularMechanismReentryAbnormal automaticityTriggered activityRecognitionBroad QRSStable and uniform beat-to-beat appearanceMonomorphic VTHeart rate:100ECG RecognitionECG used with permission of Dr.Brian Olshansky.ECG RecognitionECG used with pIntracardiac Recording of VTEGM used with permission of Texas Cardiac Arrhythmia,P.A.Intracardiac Recording of VTEGIdiopathic Right Ventricular TachycardiaRight ventricular idiopathic VTFocus originates within the right ventricular outflow tractVentricular function is usually normalUsually LBBB,inferior axisTreatment options:Pharmacologic therapy(beta blockers,verapamil)RF ablation Idiopathic Right Ventricular Kay NG.Am J Med 1996;100:344-356.ECG RecognitionKay NG.Am J Med 1996;100:34Case History:Idiopathic VTFirst episode9 hours of palpitationsIn ER,found to be in wide-complex tachycardia of LBBB,inferior axis,at 205 bpmConverted with IV lidocaine;placed on tenorminSecond episodeWhile on tenormin,patient had onset of palpitations at airportIn ER,converted with IV lidocainePatient underwent EP study39 y.o.female with no prior cardiac historyCase History:Idiopathic VTFiCase History:Idiopathic VTCase History:Idiopathic VTCase History:Idiopathic VTAt EP study,tachycardia focus was mapped and localized to right ventricular outflow tractThe focus was successfully ablatedusing radiofrequency energy,with no subsequent inducible or clinical VTCase History:Idiopathic VTAtEndocardial Activation MappingUsing an ablation catheter,map the area around and inside of the right ventricular outflow tractFind the electrograms that precede the onset of the QRS complex during tachycardiaThis area identifies the site of earliest activation,and possibly the“site of origin”of the arrhythmiaEndocardial Activation MappinPace MappingPace mapping helps to localize the“site of origin”after endocardial mapping has been performedIf the heart is paced from this region,the resulting ECG should be identical to the ECG taken during tachycardiaDelivering RF energy to this site usually eliminates ventricular tachycardiaPace MappingPace mapping helpsIdiopathic VT Ablation in RVOTRAORAOIdiopathic VT Ablation in RVOTIdiopathic Left Ventricular TachycardiaRBBB/LAFBInvolves the Purkinje networkTreatment options:RF ablationPharmacologic therapy(verapamil,beta blockers)Idiopathic Left Ventricular TECG used with permission of Kay NG.ECG RecognitionECG used with permission of KaBundle Branch ReentryReentry circuit is confined to the left and right bundle branchesUsually LBBB,during sinus rhythmPresents with:SyncopePalpitationsSudden cardiac deathTreatment:RF ablation of right bundleBundle Branch ReentryReentry cReentry circuit(fast and slow pathway)is confined to the ventricles and/or bundle branchesDifferentiate types of ventricular tachycardias using ECG and intracardiac electrogram recordingsP waves and QRS complexes not presentVentricular TachycardiaMechanisms of VTIf the heart is paced from this region,the resulting ECG should be identical to the ECG taken during tachycardiaDifferentiate types of ventricular tachycardias using ECG and intracardiac electrogram recordingsReentrant ventricular arrhythmiasIdiopathic VTRF ablationConverted with IV lidocaine;placed on tenorminPossible CausesPharmacologic therapy(beta blockers,verapamil)Rhythm:IrregularSustained VTRF ablationVT Due to Bundle Branch ReentryReentry circuit(fast and slowCatheter Ablation of Right Bundle BranchCourtesy of Dr.Warren JackmanIIIV1RACurrentVoltageCatheter Ablation of Right BunVentricular FlutterHeart rate:300 bpmRhythm:Regular and uniformMechanism:ReentryRecognition:No isoelectric intervalNo visible T waveDegenerates to ventricular fibrillationTreatment:CardioversionVentricular FlutterHeart rate:Ventricular FibrillationHeart rate:Chaotic,random and asynchronousRhythm:IrregularMechanism:Multiple wavelets of reentryRecognition:No discrete QRS complexesTreatment:DefibrillationVentricular FibrillationHeart ECG RecognitionP waves and QRS complexes not presentHeart rhythm highly irregularHeart rate not definedECG RecognitionP waves and QRSPolymorphic VTPolymorphic VTPolymorphic VTHeart rate:VariableRhythm:IrregularMechanism:ReentryTriggered activityRecognition:Wide QRS with phasic variationTorsades de pointesPolymorphic VTHeart rate:VarECG RecognitionEGM used with permission of Texas Cardiac Arrhythmia,P.A.ECG RecognitionEGM used with pTorsades de Pointes(TdP)Heart rate:200-250 bpmRhythm:IrregularRecognition:Long QT intervalWide QRSContinuously changing QRS morphologyTorsades de Pointes(TdP)HeartMechanismEvents leading to TdP are:HypokalemiaProlongation of the action potential durationEarly afterdepolarizationsCritically slow conduction that contributes to reentryMechanismEvents leading to TdPECG RecognitionQRS morphology continuously changesComplexes alternates from positive to negative ECG RecognitionQRS morphology Possible CausesDrugs that lengthen the QT:QuinidineProcainamideSotalolIbutilidePhysicalIschemiaElectrolyte abnormalitiesPossible CausesDrugs that lengTreatmentPharmacologic therapy:PotassiumMagnesiumIsoproterenolPossibly class Ib drugs(lidocaine)to decrease refractoriness/shorten length of action potentialOverdrive ventricular pacingCardioversionTreatmentPharmacologic therapySummaryVT ablation is not an FDA-approved indicationRF catheter ablation can be a useful technique in patients with ventricular tachycardiaSuccess largely depends on the etiology of the arrhythmiaUnstable sustained VT,polymorphic VT and ventricular fibrillation are not ablatableImproved catheters and imaging techniques may change this in the futureSummaryVT ablation is not an F谢谢观看谢谢观看45
展开阅读全文