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Biomedicalsignalprocessing1NankaiUniversity,CYLI,24/10/23Ch4:心电信号的处理心电图的产生,心电图处理的基本思路,时间上:动态和静态,空间上:心肌电特性的空间离散度,心电图处理和分析的发展,Biomedicalsignalprocessing2NankaiUniversity,CYLI,24/10/23心电信号的形成（1）心肌细胞的动作电位心肌细胞除极和复极的电生理现象,极化状态(polarised):静息电位(restingpotential),动作电位(actionpotential,AP):除极(depolarisation)和复极(repolarisation),mV-90-600+200心室肌细胞动作电位示意图1234300msBiomedicalsignalprocessing3NankaiUniversity,CYLI,24/10/23心电信号的形成（2）电兴奋的传导(conductionorspreadofelectricalexcitation)窦房结:心脏的起搏兴奋点,其细胞自发产生50-100次/分的可传导AP,心房的传导:心房传导束-->右心房-->左心房传导系统的传播:房室束-->希氏束-->左、右分支-->普金野（Purkinje）纤维网->心室肌,电兴奋通过Purkinje网使心室肌细胞兴奋，Biomedicalsignalprocessing4NankaiUniversity,CYLI,24/10/23心脏传导系统Biomedicalsignalprocessing5NankaiUniversity,CYLI,24/10/23Englishterms窦房结:sinusnode,心房:atrium,心室:ventricle,房室结:atrioventricularnode(junction),希氏束:bundleofHis,普金野纤维:Pukinjefibres,心脏表面(心外膜):epicardium,心内膜：endocardium体表：bodysurfaceBiomedicalsignalprocessing6NankaiUniversity,CYLI,24/10/23心电信号的形成（3）心电图(electrocardiogram,ECG)的产生电流源：每个心肌细胞的除极和复极过程等效于一个偶极子层（dipolelayer）容积导体(volumeconductor):人体组织是导电的，看作是一个容积导体，心电向量:所有心肌细胞的偶极子场的向量和,心电图：所有心肌细胞的偶极子场在容积导体内产生电场，从而有电位差产生，即心电图。体表心电图,心外膜、心内膜电图,希氏束电图，Biomedicalsignalprocessing7NankaiUniversity,CYLI,24/10/23典型心电信号波形P,QRS,ST,TS-T段QRSTPQTBiomedicalsignalprocessing8NankaiUniversity,CYLI,24/10/23心电图的记录(RecordingofECG)标准导联,肢体导联,胸导联,体表多部位标测(bodysurfacemapping),32-512通道的数据采集系统(multi-channeldataacquisitionsystem),,电极背心,(electrodevest)心脏表面的多部位标测(epicardialmapping),多通道的数据采集系统电极套(electrodesock)心脏内膜的多部位标测(endocardialmapping),多通道的数据采集系统导管(catheter)和伞电极Biomedicalsignalprocessing9NankaiUniversity,CYLI,24/10/23BodysurfacemappingBiomedicalsignalprocessing10NankaiUniversity,CYLI,24/10/23EpicardialelectrodesockBiomedicalsignalprocessing11NankaiUniversity,CYLI,24/10/23标准导联(1)12标准导联(standardleads)标准I，II，III肢体导联(bipolarlimbleads),IIIIIIIIIIIIRRFFLLR:rightarmR:rightarmL:leftarmL:leftarmF:leftfootF:leftfootI=EI=ELL-E-ERR,,II=EII=EFF-E-ERR,,III=EIII=EFF-E-ELLBiomedicalsignalprocessing12NankaiUniversity,CYLI,24/10/23标准导联(2)加压肢体导联标准aVR,aVL,aVF(augmentedunipolarlimbleads),LLWilsonterminal:Wilsonterminal:CC点的电位点的电位,,aVLaVL和和aVFaVF的的连接相似连接相似R/2R/2RRRRRRFFCCaVaVRR++--Biomedicalsignalprocessing13NankaiUniversity,CYLI,24/10/23标准导联(3)单极胸导联V1-V6(unipolarprecordialleads),precordial:chestwall,中心电端(Wilsonterminal)V1-V6,胸前电极分别与中心电端的电位差,Biomedicalsignalprocessing14NankaiUniversity,CYLI,24/10/23心电信号的畸变心脏的病变：传导阻滞，早搏，室颤、房颤,心肌缺血、梗塞等,QRS变宽,ST段位移出现,心率变化等,来自心脏外的干扰信号：50Hz工频干扰肌电干扰，10-300Hz,呼吸的干扰，使基线漂移加剧，Biomedicalsignalprocessing15NankaiUniversity,CYLI,24/10/23心电信号的预处理抑制工频干扰，...