Small Animal ECGs: An Introductory Guide, Second Edition

128 Pages·2007·5.9 MB·English

by  Mike Martin(auth.)

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Small Animal ECGs
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Dedication
Tomyfamily:mywifeMary
andourthreesons,David,DennisandSean
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Small Animal ECGs
An introductory guide
Second Edition
Mike Martin
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(cid:2)C 2000,2007MikeMartin FirstEditionpublished2000byBlackwellPublishingLtd
SecondEditionpublished2007byBlackwellPublishingLtd
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BlackwellPublishingLtd,9600GarsingtonRoad, ISBN:978-1-4051-4160-4
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Tel:[phone] LibraryofCongressCataloging-in-PublicationData
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Ames,Iowa50014-8300,USA Martin,MikeW.S.
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Carlton,Victoria3053,Australia Includesbibliographicalreferencesandindex.
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TherightoftheAuthortobeidentifiedastheAuthorofthisWorkhas 1.Veterinaryelectrocardiography. I.Title.
beenassertedinaccordancewiththeCopyright,DesignsandPatents [DNLM:1.Electrocardiography–veterinary. 2.Animals,Domestic.
Act1988. SF811M382s2007]
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C
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Contents e
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s
Prefacetosecondedition x
Prefacetofirstedition xi
Abouttheauthor xii
Acknowledgements xiii
Part1: Understandingtheelectricityoftheheartandhow
itproducesanECGcomplex 1
1 WhatisanECG? 3
2 Theelectricityoftheheart 4
FormationofthenormalP–QRS–Tcomplex 4
NomenclatureoftheQRScomplex 8
3 Rhythmsofsinusorigin 9
Sinusrhythm 9
Sinusarrhythmia 9
Sinustachycardia 10
Sinusbradycardia 11
Part2: Abnormalelectricityoftheheart 13
4 Recognisingandunderstandingectopia 15
FirstidentifythemorphologyofthenormalQRScomplex 15
Themorphologyofanectopicventriculardepolarisation 15
Themorphologyofanectopicsupraventriculardepolarisation 18
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e 5 Arrhythmiasassociatedwithectopia 23
d
ui Ventricularprematurecomplexes 23
G Supraventricularprematurecomplexes 30
y
r Escaperhythms 31
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ct AVdissociation 34
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d Fibrillation 34
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n 6 Abnormalitiesintheconductionsystem 40
I
n Sinusarrestandblock 40
A
– Sicksinussyndrome 40
s
G Atrialstandstill 42
C
E Heartblock 43
al
m 7 ChangesintheP–QRS–Tmorphology 48
ni Wanderingpacemaker 48
A
all Changesassociatedwithchamberenlargement 48
m Leftatrialenlargement 49
S
Rightatrialenlargement 49
Leftventricularenlargement 50
Rightventricularenlargement 50
Abnormalmeanelectricalaxis(MEA) 50
Low-voltageQRScomplexes 51
Electricalalternans 52
NotchingintheRwave 52
Q–Tintervalabnormalities 53
S–Tsegmentabnormalities 53
AbnormalitiesoftheTwave 53
Hyperkalaemia 55
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Part3: Moreadvancedelectrocardiography 57 C
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8 UnderstandingtheECGlimbleadsystems 59 t
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n
ThesixECGlimbleads 59 t
s
9 Meanelectricalaxisexplained 61
Howtocalculatethemeanelectricalaxis 62
10 Intraventricularconductiondefects 64
Rightbundlebranchblock 64
Leftbundlebranchblock 65
Leftanteriorfascicularblock 67
Intermittentventricularaberrancy 69
11 Someadditionalarrhythmias 70
Ventricularpre-excitation 70
Atrialflutter 70
Acceleratedidioventricularrhythm 71
Part4: Managementandtreatmentofarrhythmias 73
12 Managementofarrhythmias 75
Doesthearrhythmiasuggestthepresenceofanunderlyingcondition? 75
Isthearrhythmiaofprimaryclinicalsignificance? 76
13 Treatmentofarrhythmias 78
Bradyarrhythmias 78
Tachyarrhythmias 81
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e 14 Pacemakers 88
d
ui Indications 88
G Contraindications 88
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r Disadvantages 88
o
ct Complications 88
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d Priordiagnostics 89
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tr Equipment 89
n
I Typesofpermanentpacemakers 89
n
A Techniquesofimplantation 90
–
s Pacemakerfollow-up 90
G
C Hazards 90
E
al
m Part5: RecordingandinterpretingECGs 91
ni
A 15 ApproachtointerpretationoftheECGrecording 93
all Tocalculatetheheartrate(givenasbeatsperminute) 93
m
S Determinetherhythm 93
Measurethecomplexamplitudesandintervals 94
16 Artifacts 96
Electricalinterference 96
Muscletremorartifact 97
Movementartifact 97
Incorrectlyplacedelectrodes 100
17 RecordinganECG 102
Theconnectors(electrodes) 102
Makingtheconnection 102
Wheretoplacetheelectrodes 103
Isolatingtheelectrodes 104
HowtopositiontheECGcables 104
Positioningtheanimal 104
SettingupandpreparingtheECGmachine 109
RecordinganECG–asuggestedroutine 111
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18 ChoosinganECGrecorder 114 C
o
Quality 114 n
t
Continuousrecording 114 e
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Easeofuse 114 s
Automaticlabelling 114
Automaticvs.manualrecordingmode 114
Interpretativesoftware 115
Multichannelvs.singlechannel 116
Precordialchestleads 117
Calibrationsettings 117
Automaticcentringvs.manualcontrol 117
Internalbattery 117
Jackplugleadfitting 117
Monitorscreen 118
Thermalpapervs.inkpaper 118
Newvs.second-hand 118
SummaryoffeaturestolookforinanECGrecorder 118
Furtherreading 119
Index 120
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G Preface to second edition
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n Thiseditionhasbeensignificantlychangedandupdated,Ihopefor ThiseditioncontainsmorethanfiftynewECGtracings,gradually
I
n thebetter.Itisstillaimedatthebeginner,betheyaveterinarystudent gatheredovertheyears.Itishopedthatthesewilladdgreatlytothe
A
– orgraduate,veterinarynurseortechnician.Itisintendedasanintro- book,providingillustrationstomatchthetext.Therearenewchap-
s
G duction,providingafairlyeasybooktoreadandlearnaboutelectro- tersonmanagementandtreatmentofarrhythmiasandonchoosing
C
E cardiography,priortoembarkingonthemoreestablishedtextbooks anECGrecorder.
mal listedintheFurtherReadinglist. Thepositivefeedbacktothe1steditionwasverygratifyingandis
ni IncontinuingtolecturewidelyonECGs,Ifoundthatthesequence alwaysapleasuretoreceive.Ihopethatthisneweditionhasatleast
A
inwhichItaughtwasdifferentfromthatinmyownbook(the1st an equally good reception: hopefully even better. I wish you all an
mall edition).Sointhis2ndedition,Ihavere-arrangedthesequenceto enjoyablebeginningtoelectrocardiographyandalife-longusethat
S matchmylecturecourse.Ihopethisworks.Ibelieveitshouldbut, willcontinuetoevolvewithtimeandexperience.
importantly,itshouldmakereadingandlearningaboutECGsmuch
easierandmorelogical.Hopefully,itwillhelpthereadertoovercome MikeMartin
any psychological fear and apprehension about understanding, in-
terpretingandmakinggooduseofECGs,andspreadtheuseofECGs
morewidely.
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