EKG心電圖入門知識-英文版 2010留學生-小講課 (2)-總醫(yī)院

ELECTROCARDIOGRAPHYBianBoTianjinMedicalUniversityGeneralHospital1FocusofECGRateandrhythmIshemiaHyperthrophyothers2Questionstoanswerinordertoidentifyanunknownarrhythmia:1.Istherateslow(<60bpm)orfast(>100bpm)? SlowSuggestssinusbradycardia,sinusarrest,or conductionblock FastSuggestsincreased/abnormalautomaticityorreentry2.Istherhythmirregular? IrregularSuggestsatrialfibrillation,2nddegreeAVblock, multifocalatrialtachycardia,oratrialflutterwithvariable AVblock3.IstheQRScomplexnarroworwide? NarrowRhythmmustoriginatefromtheAVnodeorabove WideRhythmmayoriginatefromanywhere3Questionstoanswerinordertoidentifyanunknownarrhythmia:4.AretherePwaves? AbsentPwavesSuggestsatrialfibrillation,ventricular tachycardia,orrhythmsoriginatingfromtheAVnode

5.WhatistherelationshipbetweenthePwavesandQRScomplexes? MorePwavesthanQRScomplexesSuggests2ndor3rddegreeAVblockMoreQRScomplexesthanPwavesSuggestsanacceleratedjunctionalorventricularrhythm6.Istheonset/terminationoftherhythmabruptorgradual? AbruptSuggestsreentrantrhythm GradualSuggestsalteredautomaticity4StepstoInterpretinganECGRateRhythmAxisIntervals(PR,QRS,QTc)Amplitudes,Morphology(P,QRS)STsegmentsTwavesQwaves5Rate-PaperWhatarethetimeintervalsbetweenlines?0.2sec200msec0.04sec40msecNormalpaperspeedis25mm/sec6StepstoInterpretinganECGRateRhythmAxisIntervals(PR,QRS,QTc)Amlitudes,Morphology(P,QRS)STsegmentsTwavesQwaves7

NormalSinusrhythmfeatures(1)EveryPwaveisfollowingbyaQRScomplex;

(2)PwaveisuprightinleadI,II,aVF,V4-V6,inverseinaVR;Samemorphology(3)

P-Rinterval:0.12-0.20sec(4)

Normalrateis60-100beats/min8NormalSinusrhythm91011FirstDegreeA-VBlockProlongedP-Rinterval:

P-Rinterval>0.20sec.inadults(varieswithheartrate)

121stDegreeAVBlockEKGCharacteristics:ProlongationofthePRinterval,whichisconstant AllPwavesareconducted13SecondDegreeA-VBlock(1)MobitztypeI(Wenckebachphenomenon).ThepatternisaprogressiveprolongationoftheP-Rintervaluntilabeatisdropped.ThefirstbeatafterthepausehastheshortestP-Rinterval,whichmayormaynotbenormal.14152ndDegreeAVBlockType1(Wenckebach)EKGCharacteristics: ProgressiveprolongationofthePRintervaluntilaP waveisnotconducted. AsthePRintervalprolongs,theRRintervalactually shortensEKGCharacteristics: ConstantPRintervalwithintermittentfailuretoconductType216(2)MobitztypeIIThereisafixednumericalrelationshipbetweenatrialandventricularimpulses,whichmaybe2:1(2atrialbeatstooneventricularbeat)or3:1or4:1.1718ThirdDegreeA-VBlock

(Completeheartblock)Theatrialandtheventricularrhythmsareabsolutelyindependentofoneanother.(ThereisnorelationshipofPtoQRS.)(2)atrialrate>ventricularrate.QRSis0.12sec.orgreater.193rdDegree(Complete)AVBlockEKGCharacteristics: NorelationshipbetweenPwavesandQRScomplexesRelativelyconstantPPintervalsandRRintervalsGreaternumberofPwavesthanQRScomplexes20StepstoInterpretinganECGRateRhythmAxisandIntervals(PR,QRS,QTc)Amlitudes,Morphology(P,QRS)STsegmentsTwavesQwaves21TheQRSAxisBynear-consensus,thenormalQRSaxisisdefinedasrangingfrom-30°to+90°.-30°to-90°isreferredtoasaleftaxisdeviation(LAD)+90°to+180°isreferredtoasarightaxisdeviation(RAD)22IntervalsSTPRQRSQTNormalPR 0.12–0.20QRS <0.12QT <0.4423StepstoInterpretinganECGRateRhythmAxisandIntervals(PR,QRS,QTc)Amplitudes,Morphology(P,QRS)STsegmentsTwavesQwaves24tallPwavesinleadII(rightatrialabnormality）25anabnormallylargeterminalnegativecomponentofthePwaveinleadV1(leftatrialabnormality)26LVH“SV1+RV5orV6>35mm”27IftheinitialcomponentofabiphasicPwave(inV1)islargest,thisisRightatrialenlargement.PositivecomponentofthePwaveinleadV1

orV2＞1.5mmIftheheightofthePwaveinanyofthelimbleadsexceeds2.5mm(ppulmonale),suspectRightAtrialenlargementRIGHTATRIALABNORMALITY28LEFTATRIALABNORMALITYProlongedPwavedurationof>110msecinleadIIProminentnotchingofthePwave,usuallymostobviousinleadII,withanintervalbetweenthenotchesof>40msec(pmitrale)IncreaseddurationanddepthoftheterminalnegativeportionofthePwaveinleadV1(thePterminalforce)sothattheareasubtendedbyitexceeds0.04mm-sec29StepstoInterpretinganECGRateRhythmAxisandIntervals(PR,QRS,QTc)Amlitudes,Morphology(P,QRS)STsegmentsandTwavesQwaves30TypesOf

STSegmentDepression31TheQScomplexes,resolvingSTsegmentelevationandTwaveinversionsinV1-2areevidenceforafullyevolvedanteroseptalMI.TheinvertedTwavesinV3-5,I,aVLarealsoprobablyrelatedtotheMI.

3233SignificantQWavesAnabnormalQwaveisdefinedbythefollowingcriteria：(1)Qdurationof0.04sorgreater(2)Q:Rratio=