室性心律失常EP综述（英文版） .ppt
An Electrophysiologic OverviewVentricular TachyarrhythmiasModule Objectives Ventricular Tachyarrhythmias Identify the mechanisms for ventricular tachycardias Differentiate types of ventricular tachycardias using ECG and intracardiac electrogram recordings Discuss treatment options for ventricular tachycardiasAfter completion of this module,the participant should be able to:Module Outline Ventricular TachyarrhythmiasI.DescriptionII.CharacteristicsA.MechanismsB.Sustained vs.nonsustainedC.Premature ventricular contractionsModule Outline Ventricular TachyarrhythmiasIII.ClassificationA.Monomorphic1.Idiopathica.Descriptionb.ECG recognitionc.Treatment ablation2.Bundle brancha.Descriptionb.ECG recognitionc.Treatment ablationModule Outline Ventricular TachyarrhythmiasIII.Classifications-continued3.Ventricular fluttera.ECG recognition4.Ventricular fibrillationa.ECG recognitionB.Polymorphic1.Torsades de pointesa.Descriptionb.ECG recognitionc.TreatmentIV.SummaryVentricular Tachycardia(VT)Originates in the ventricles Can be life threatening Most patients have significant heart diseaseCoronary artery diseaseA previous myocardial infarctionCardiomyopathyMechanisms of VT Reentrant Reentry circuit(fast and slow pathway)is confined to the ventricles and/or bundle branches Automatic Automatic focus occurs within the ventricles Triggered activityEarly afterdepolarizations(phase 3)Delayed afterdepolarizations(phase 4)Reentrant Reentrant ventricular arrhythmiasPremature ventricular complexesIdiopathic left ventricular tachycardiaBundle branch reentryVentricular tachycardia and fibrillation when associated with chronic heart disease:Previous myocardial infarctionCardiomyopathyAutomatic Automatic 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 toneAutomaticityAbnormal Acceleration of Phase 4Fogoros:Electrophysiologic Testing.3rd ed.Blackwell Scientific 1999;16.Triggered Triggered activity ventricular arrhythmiasPause-dependent triggered activityEarly afterdepolarization(phase 3)Polymorphic ventricular tachycardiaCatechol-dependent triggered activityLate afterdepolarizations(phase 4)Idiopathic right ventricular tachycardiaTriggeredFogoros:Electrophysiologic Testing.3rd ed.Blackwell Scientific 1999;158.Sustained vs.Nonsustained Sustained 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 secondsPremature Ventricular Contraction PVCEctopic beat in the ventricle that can occur singly or in clustersCaused by electrical irritability Factors influencing electrical irritabilityIschemiaElectrolyte imbalancesDrug intoxicationClassification Ventricular TachycardiaMonomorphicIdiopathic VT Bundle branch reentry tachycardiaVentricular flutterVentricular fibrillationPolymorphicTorsades de pointes(TdP)Monomorphic VTsMonomorphic VT Heart rate:100 bpm or greater Rhythm:Regular MechanismReentryAbnormal automaticityTriggered activity RecognitionBroad QRSStable and uniform beat-to-beat appearanceECG RecognitionECG used with permission of Dr.Brian Olshansky.Intracardiac Recording of VTEGM used with permission of Texas Cardiac Arrhythmia,P.A.Idiopathic Right Ventricular Tachycardia Right ventricular idiopathic VTFocus originates within the right ventricular outflow tractVentricular function is usually normalUsually LBBB,inferior axis Treatment options:Pharmacologic therapy(beta blockers,verapamil)RF ablation Kay NG.Am J Med 1996;100:344-356.ECG RecognitionCase History:Idiopathic VT First episode9 hours of palpitationsIn ER,found to be in wide-complex tachycardia of LBBB,inferior axis,at 205 bpmConverted with IV lidocaine;placed on tenormin Second episodeWhile on tenormin,patient had onset of palpitations at airportIn ER,converted with IV lidocaine Patient underwent EP study39 y.o.female with no prior cardiac historyCase History:Idiopathic VTCase History:Idiopathic VT At EP study,tachycardia focus was mapped and localized to right ventricular outflow tract The focus was successfully ablatedusing radiofrequency energy,with no subsequent inducible or clinical VTEndocardial Activation Mapping Using an ablation catheter,map the area around and inside of the right ventricular outflow tract Find the electrograms that precede the onset of the QRS complex during tachycardia This area identifies the site of earliest activation,and possibly the“site of origin”of the arrhythmiaPace Mapping Pace mapping helps to localize the“site of origin”after endocardial mapping has been performed If the heart is paced from this region,the resulting ECG should be identical to the ECG taken during tachycardia Delivering RF energy to this site usually eliminates ventricular tachycardiaIdiopathic VT Ablation
