内科学精品教学课件（时国朝）07 心律失常 8年制2015

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1、心律失常（CardiacArrhythmia)Dr.WeiMeng,MD,FACCDepartmentofcardiology,affiliated6thpeople’shospital,ShanghaiJiaoTongUniversityMechanismofarrhythmiaPropertyofcardiacelctrophysiology兴奋性（Excitability)自律性(automaticity)传导性(Conductivity)ExcitabilityExcitabilityindicatesthatmyocardialcellhaselectricalactivit

2、ywhenitisstimulatedElectricalactivityofsinglemyocardialcelliscalledactionpotential(AP)ElectricalactivityofwholeheartmakesECG0-60-90+20Thresholdvoltagemv01234ARPERPRRPSuper-conductiveperiodARP:AbsoluteRefractoryperiod;ERP:EffectiveRefractoryperiod;RRP:RelativeRefractoryperiodConductivityElectrica

3、limpulsecanconductinmyocardialtissuebidirectionallyNormalconductionpathway：sinusnode→intranodebundle→atrioventriculanodeandintraatrialbundle→Hisbundle→rightandleftbundlebranch(includingleftanterosuperiorandposteroinferior)→Purkinjefiber→myocardiumautomaticityCellsspontaneouslydischarging(spontan

4、eousAP,diastolicdepolarization)Automaticityincreasesfromhightolowasfollows:Physiologicalstatus：SN、AVN、HIS、Purkinjepathological：diseasedmyocardialandconductivetissue,etc.PropertyofnormalrhythmImpulsefromSNHeartrateiswithin60～100/minRegularrhythm，PPinterval＜0.12sPRintervalisbetween0.12～0.20s，QRSco

5、mplexduration＜0.10sFrontalaxiswithin-30～110°ItisconsideredasarrhythmiaifanyitemaboveisnotmatchedMechanismsofarrhythmogenesisEnhancedautomaticityTriggeredactivityAutomaticcellsdiminishormalfunction,DysfunctionofconductivetissuesReentryMechanismsofarrhythmogenesis(1)EnhancedautomaticityEndogenouso

6、rexogenouscatecholamineincreasingAbnormalityofacid,basic,electrolytebalanceIschemia,hypoxiaMechanicalstretchdrugsDisturbanceofnerveandliquidmodulationMechanismsofarrhythmogenesis(2)TriggeredactivityDepolarizingoscillationsofmembranevoltageinducedbyabnormalinwardNa+current(oneormoreprecedingAP)du

7、ringearlierorlaterreporlarization,ie,AfterdepolarizationEarlydepolarizationDelayeddepolarizationMechanismsofarrhythmogenesis(3)Automaticcellsdiminishormalfunction,suchassicksinussyndromeDysfunctionofconductivetissues,suchass