心肌梗死患者抢救消融电风暴英文课件(1)

Rescue Ablation of Electrical Storms in a Patient with Remote Myocardial InfarctionKatherine FanGrantham HospitalHong Kong SARPatient Mr. Ln M/64n History of inferior MI 1989- MVR for papillary muscle rupture and severe MRn Ischemic cardiomyopathy (EF 30%)n VT 1997- ICD implanted / generator change 2002n Chronic smoker/ COPDVentricular Arrhythmiasn ICD (single-chamber) 1997n Amiodarone added in 2001 for PAF/ NSVTn Recurrent VT episodes in 3/2005 with increased dosage of amiodaronen Developed SOB- diagnosed amiodarone induced pulmonary fibrosis: Amiodarone stopped/ High dose steroids requiredn -blockers / sotalol- not tolerated exacerbation of COPDn Recurrent VT episodes- mexiletine started but complicated by neurological signs (limb tremor and gait instability)Electical Stormsn Nov 2005- admitted after recurrent ICD shocksn Interrogations: n 58 episodes of VT detectedn Most terminated with ATPn Some accerlerated to fast VT which was then termianted with cardioversion shocksn Early re-initiation of VTVT MorphologiesLBBB/ Left superior axis QRS RBBB/ Right superior axis QRSATPRBBB/R sup LBBB/ L sup RBBB/ R supMitral valve prothesisRAO INFSinus RhythmVT 1VT 2Lesions CreatedTermination of VT (RF #38!)on RFCatheter Ablation of the Mitral Isthmus for VT associated with Inferior InfarctionWilber et al. Circulation 1995;92:3481-3489By virtue of its narrow dimension, the isthmus became the vulnerable point to interrupt this circumferential activationRBBB/ Right superior axisLBBB/Left superior axisMitral Isthmus Ventricular Tachycaridan Critical zone of slow conduction activated parallel to mitral isthmus in either direction resulting in 2 distinct but characteristic QRS configurationsn LBBB with left superior axis- rS in V1 and aVR/ R in V6, I, aVLn RBBB with right superior axis- R in V1 and aVR/ QS in V6, I, aVLLBBB/LAD RBBB/RADWilber et al. Circulation 1995Dynamic Substrate MapSinus RhythmLow Voltage Zone RAO view Inferior viewDynamic Substrate MapVentricular TachycardiaRAO view Inferior viewLow Voltage Zone Composite Substrate ProfileDSM Sinus Rhythm Composite Substrate Map DSM VTFixed BlockFunctional BlockMarked LesionsRAO view Inferior viewAnother Marked LesionsRAO view Inferior viewSubstrate-Orientated VT Ablationn A definite trigger or delineated scar has been characterized as a requirement for substrate orientated ablation of intractable unmappable VTn Targetsn Critical isthmusn Areas of slow conductionn Exit sites- often located at the border of the scarred myocardiumScar Border Zone Substraten VT originated from area of diseased tissue surrounding dense scarn Based on surgical approaches to treat VT (sub-endoardial resection), methods of ablating ischemic VT by “ substrate mapping” in SR have been used successfully in pts with drug refractory hemodynamically unstable MMVTn Use electroanatomical voltage mapping to define regions of scar and viable endocardium in SR followed by ablations in the border zone regionsAnatomical vs Functional SubstrateLimitation of Voltage Mapping during SRn Boundaries of the isthmus could be functional lines of block not detected during SRn Dispersion of voltage (heterogeneity) in scar areas may appear only when activated at VT rate and/or orientationn Post MI structural remodeling Alteration of anisotropy depended on electrotonic loads and orientationSummaryn Successful ablation of mitral isthmus for VT associated with remote inferior infarctionn Characteristic of VT morphologies and its corresponding activation mappings demonstratedn Dynamic substrate mapping during SR and VT provided complimentary data on substrate identification (anatomical vs functional)Ventricular Tachycardia 1Ventricular Tachycardia 2Relationship Between Successful Ablation Sites and the Scar Border Zone Defined by Substrate Mapping for Ventricular Tachycardia Post-MIVerma et al. JCE 2005:16:465-47129598 15 792 3* Dense scar= bipolar voltage 0.5mVSuccessful Ablation Within Scarn Critical isthmus may originate in scar and exit in border zone or may exist entirely within scarn Thin strands of surviving myocytes “zigzagging” through dense areas of scar- substraten Thick layers of survivung myocardium existing beneath dense endocardial scar- ?return path of circuitn Linear ablations that extend outside of the scar border and into the regions of dense infarction may be requiredn Some advocated targeting sites within scar by identification of isolated, delayed components of local EGMAnatomical Substrate vs Electrophysiological Substraten Anisotropy- determined by cell orientation/ morphology and cell-to-cell connections (gap junctions) n Diseased state (eg MI/ heart failure)- structural remodeling alters the ansiotropy and increases its heterogeneity and potential for arrhythmia developmentn ? Extent of “ functional substrate” depends on the electrotonic loads and orientationn Entrainment mapping