class心電圖英文教程培訓(xùn)課件

1、Questions from Class 1Technician versus Technologist: any difference?Technician: a person skilled in the performance of the technical or procedural aspects of a health care profession. The technician carries out routine work under the supervision of a physician, therapist, technologist, or other hea

2、lth care professional. Technologist: a person skilled in the theory and practice of a technical profession, usually with at least a baccalaureate degree; in several allied health fields, technologist is the highest professional rank. Source: Questions from Class 1TechniciQuestions from Class 1Pay Sc

3、ale (example: The Ottawa Hospital)Registered Cardiology Technologist (ECG Technician)$21.59 24.85Cardiac Diagnostic 2 Stress/Holter Technologist$25.55 34.28Questions from Class 1Pay ScalQuestions from Last WeekTextbook? In Bookstore:Course 1Electrocardiography for Health Care PersonnelCourse 2ACSMs

4、Guidelines for Exercise Testing and Prescription, 7th ed.Housekeeping PAR-QQuestions from Last WeekTextboClass 2 - AgendaOperating Principles of Diagnostic EquipmentElectrocardiographElectrodesPiezoelectric sensorsPhotoelectric sensorsECGsTheoryClinical considerationsProceduresClass 2 - AgendaOperat

5、ing PrinBioelectric PotentialsDefined as electrical voltages originating from a living sourceAll cells have an electrical potential (voltage) across their membranesWhy?Differences in concentration of ions between the inside and outside of the cellIons moving down concentration gradients across semi-

6、permeable membranesBioelectric PotentialsDefined Membrane PotentialsK+K+K+K+-+Potassium equilibrium potential:Electrical forces pulling K+ in balance the concentration forces driving K+ out- 90 mVMembrane PotentialsK+K+K+K+-Membrane PotentialsSodium equilibrium potential:+ 60 mVCa2+ also participate

7、sNa+Na+Na+Na+-+-Membrane PotentialsSodium equiCardiac Membrane PotentialsAt rest, most are close to the K+ equilibrium potentialA rapid change in membrane potential from negative to positive and back again is called an action potential2 Phases: polarization (“rest”) and depolarizationDue to changes

8、in permeability of the cell membrane to K+, Na+ and Ca2+.Followed by contraction of the muscle cellRepolarization is the process of cellular recovery Regain internal negativityAllows for filling of heart chambersCardiac Membrane PotentialsAt Cardiac Cell Action PotentialPhases0 depolarization1 overs

9、hoot2 plateau3 repolarization4 resting MP1Cardiac Cell Action PotentialPCardiac vs Skeletal MuscleCardiac action potentials:Can be self-generatingCan be conducted directly from cell to cellHave long durations (refractory state)Pacemaker cells can initiate APSA nodal cells reach threshold potential f

10、irst and act as the normal pacemakerAV nodal cells have next fastest spontaneous depolarization (latent pacemaker)Cardiac vs Skeletal MuscleCardElectrocardiographDepicts the electrical events occurring in the heartMeasured with electrodes on body surfaceRecords how the voltage changes between 2 poin

11、tsShows net electrical field (sum of electrical fields produced by individual cardiac cells)ElectrocardiographDepicts the ElectrocardiographSignals very small amplifiedGalvanometer converts electrical activity to mechanical actionRecording inscribed on heat sensitive graph paperElectrode Lead Amp Ga

12、lv. Stylus ElectrocardiographSignals veryComputerized ECGIn addition to the ECG tracing:Computerized measurement and analysisStorage of recordsCommunication transmit results over telephone or fax lines, or InternetComputerized ECGIn addition toControlsSpeedHow quickly the ECG paper runsStandard rate

13、 is 25 mm/secChange to 5 or 10 mm/sec on MD requestNote on ECGGainRegulates height of ECG waveformStandard is 10 mm/mVChange to 5 or 20 mm/mVNote on ECGControlsSpeedControls, continuedFilterPresent on some machinesUsually 40 Hz (muscle tremor, slight patient movement)StylusHeated, reacts with paper

14、to produce tracingStandardizationA 1 mV signal produces a 10 mm deflection Controls, continuedFilterHistoryWilhelm Einthoven In 1903, developed the first practical galvanometer and the first ECG600 lbs6 people to operate2HistoryWilhelm Einthoven 2Single channel ECGMonitors leads individuallyMust cut

15、 and mount strips3Single channel ECG3Mounting ECG Strip4Mounting ECG Strip4Multichannel ECGMonitors all 12 leads at onceRecords 3 at once for 4 sets5Multichannel ECGMonitors all 1ECG Graph PaperGrid permits measurement of:Time (seconds) and distance (mm) on the horizontal linesVoltage/amplitude (mm)

16、 on the vertical linesDark and light lines form small and large squaresDark vertical lines are 5 mm (0.20 sec) apartLight vertical lines are 1 mm (0.04 sec) apartMarks along edge are spaced 3 sec apartECG Graph PaperGrid permits meElectrodeConductive device applied to body to record bioelectric sign

17、als2 types:Reusable bulbs and platesDisposableElectrodeConductive device appReusable ECG ElectrodesSuction chest electrodes made of nickel and/or silverBinding post connects electrode to patient leadRequires application of ECG electrode gel to conduct electrical signals6Reusable ECG ElectrodesSuctio

18、nReusable ECG ElectrodesLimb clamp electrodeUse electrode gel on the metal portionClean after each use with warm, soapy water78Reusable ECG ElectrodesLimb clDisposable Electrodes for ECGAg/AgCl sensorConductive adhesive hydrogelFor crocodile connector791011Disposable Electrodes for ECGADisposable el

19、ectrodes for Holter and Exercise TestingAg/AgCl sensorPress-stud adaptorFoam backing12Disposable electrodes for HoltPiezoelectric SensorsPiezoelectricity:Property of crystals that allows them to generate a voltage in response to mechanical stressComponent of ambulatory blood pressure systems stretch

20、ed during expansionPiezoelectric SensorsPiezoelecPhotoelectric SensorsComponent of Pulse Oximetry Principle of Differential Light AbsorptionPulses of infrared light are transmitted through tissue to a small photosensorLight passes through hemoglobin; some is absorbed in proportion to its saturation

21、with oxygenSensor on finger or ear (high perfusion of arterial blood)Determines percentage of hemoglobin that is saturated with oxygen (SpO2)Photoelectric SensorsComponentElectrocardiogram“graphical display of electrical potential differences of an electric field originating in the heart as recorded

22、 at the body surface”Eithoven W, cited in Kadish et al., Circulation. 2001;104:3169.Most common lab procedure for Dx of HDSafe, simple, reproducibleSerial studiesMinimal costFrom Kadish et al., Circulation. 2001;104:3169Electrocardiogram“graphical diElectrocardiogram12 Lead ECG consists of:6 leads i

23、n the frontal plane3 bipolar limb leads3 unipolar limb leads6 precordial leads in the transverse (horizontal) planeWho knows what colour the leads are?Electrocardiogram12 Lead ECG cStandard Limb Leads (Bipolar)Bipolar lead:One positive and one negative electrodeAnd they are.Leads I, II, and IIIStand

24、ard Limb Leads (Bipolar)BStandard Limb Leads (Bipolar)Electrodes on RA, LA, and LL Form a triangle over the thoraxEinthovens triangle13Standard Limb Leads (Bipolar)ELeads I, II, and III14Leads I, II, and III14Augmented Limb Leads (Unipolar)Unipolar:One limb electrode is positiveOther 2 are electrica

25、lly connected indifferent reference point with zero potential at center of heartThe small electrical potential is magnifiedAugmented Limb Leads (UnipolaraVR, aVL, aVFGives us:6 limb leadsFrontal plane15aVR, aVL, aVF15Precordial leads6 unipolar chest leadsV1 to v616Precordial leads6 unipolar cheAnato

26、mical LandmarksManubriumSuprasternal NotchAngle of Louis4th ICS5th ICSMidclavicular lineAnt. axillary lineMidaxillary line17Anatomical LandmarksManubrium1Anatomic placement of the chest leadsV1: 4th ICS, R of sternumV2: 4th ICS, L of sternumV3: midway between V2 and V4V4: 5th ICS, midclavicular line

27、V5: anterior axillary line, same level as V4V6: midaxillary line, same level as V418Anatomic placement of the chesAnatomical Relationship of LeadsInferior wallII, III, aVFAnterior wallV1 V4Lateral wallI, aVL, V5, V6Anatomical Relationship of LeaNon-standard LeadsRight-sided chest leads v1R V6RMore s

28、ensitive to the presence of right ventricular MIMost sensitive lead is V4RDextrocardia gives normal R wave progression19Non-standard LeadsRight-sided Posterior leads V7, V8, V9Detects posterior wall MI20Posterior leads V7, V8, V920Pediatric ECG PlacementPrincipal reason for pediatric ECG:Assessment

29、of possible chamber enlargementMD may order additional leads:RVH:Add a V3R or V4RLVH:Add a V7Pediatric ECG PlacementPrincipECG ProceduresEnsure patient ID, review indicationInpatient will have an orderCheck ID bandOutpatient will have a requisitionVerify correct patientExplain test/requirements of p

30、atientIntroduce selfExplain preparation for testPatient removes clothing above waistProvide women with a hospital gown open at frontPatient to remove jewelry interfering with electrode placementPatient supine, as comfortable as possibleECG ProceduresEnsure patient IECG ProceduresEnter demographics i

31、n ECGIdentify proper electrode sitesWork on left side of patientExpose patients chest and limbsLimb electrode sites are just above wrists and ankles (inside of lower leg)ECG ProceduresEnter demographiECG ProceduresPrepare sites and place electrodesMay need to shave small areas of chest hairRemove an

32、y oil/lotion with alcohol and gauze or alcohol swabFor women, place chest electrodes under breastAttach lead wiresShould be no tension on wiresDouble check lead placementFor women, close gownProvide sheet or blanket if patient is coldECG ProceduresPrepare sites anECG ProceduresRecord ECGRemind patie

33、nt to remain still (but breathe normally), do not talkWhere applicable, record rhythm strips and specialty leadsRemove leads and electrodes; clean sitesClean electrodes if reusableECG ProceduresRecord ECG3 Keys to Acceptable TracingTesting environmentWarmComfortablePrivateQuietTechnologists manner:

34、professional, competent, calmExplanation to the patient3 Keys to Acceptable TracingTeECG Technique ModificationsBurnsPlace limb leads in unaffected areasNote any modified chest placementsGeriatricNote thin skin prepare sites and remove electrodes gentlyTraumaPlace leads on upper arms and legs (same

35、level if possible)WheelchairECG may be done in sitting position (note on ECG)ECG Technique ModificationsBurECG Technique ModificationsRespiratory distressMay be necessary to perform test with patient sitting (note on ECG)ER, esp. AMIBe sure to leave electrodes in place for serial ECGsOncologyDo not

36、apply electrodes to radiation treatment areaECG Technique ModificationsResPediatric PatientsHow can we make the process easier?Explain without using technical termsAllow for questionsUse “stickers”Place stickers on doll, toy, parent, childs hand“Take a picture of heart”Parents stay in roomSmall chil

37、d may lie in parents armsFor infants:Cut disposable tabs in halfWait until infant is sleepingPediatric PatientsHow can we mArtifactUnwanted waves and spikes on the ECG tracing caused by sources other that the hearts electrical activityDistort the waveforms of the ECGArtifactUnwanted waves and spiGro

38、up ActivityName or cause of the artifactRemedyGroup ActivityName or cause ofArtifact 1Artifact 1Artifact 1Cause:Muscle/somatic tremorECG recording electrical voltages from skeletal muscleGives ECG jagged appearanceNervous or shivering patients, neuromuscular disordersRemedy:ReassuranceBlanketFor neu

39、romuscular conditions, patient can place hands under buttocks, or move electrodes higher on limbs (document)Artifact 1Cause:Artifact 2Artifact 2Artifact 2Cause:Alternating (AC) interference from electrical equipment due to:Improper groundingOther electrical equipment in roomLead wires crossedResults

40、 in thick baseline of 60 cycle wavesRemedy:Use battery powerUncross wiresHave ECG machine servicedArtifact 2Cause:Artifact 3Artifact 3Artifact 3Cause:Wandering baseline - Tracing drifts away from center of graph paperElectrodes loose (poor electrical contact)Tension on electrode wiresToo little elec

41、trode gelCorroded/dirty electrodesOil, lotion, dirt under electrodesRemedy:Prepare sites againUse new gel or new electrodesCheck expiry date of disposablesRemove tension from lead wiresArtifact 3Cause:Artifact 421Artifact 421Artifact 4Flat line in one or more leadsCause:Electrode looseLead connector

42、 has come offLead wire not plugged inFault/break in lead wireRemedy:Ensure all electrodes and leads attached may need to weigh electrodes down Connector may need to be replacedInspect lead wire and replaceArtifact 4Flat line in one or Reporting ResultsFor inpatients:Leave printout at nursing station

43、If abnormal, compare to previous in chartDownload ECGs to databasePhysician reads onlineDeliver interpreted copy to nursing stationFor pre-op appt or patient seeing cardiologist:Place uninterpreted ECG in an envelopeReporting ResultsFor inpatientACC/AHA Clinical Competence Statement on Electrocardio

44、graphy and Ambulatory Electrocardiography /cgi/content/full/104/25/3169Circulation. 2001;104:3169.) 2001 American Heart Association, Inc.Discusses:Technical AspectsComputer InterpretationACC/AHA Clinical Competence StTechnical Aspects of ECG RecordingPatient-related factors:Muscle tremor, movementVariations in body habitusMarked obesityChronic lung diseaseOperator-dependent factorsI