Life-threatening cardiac emergencies for the small animal practitioner

100 Pages·2016·22.43 MB·English

by  Fries

Life-Threatening
Cardiac Emergencies
for the Small Animal
Practitioner
The Rapid Reference Series
Books in the Rapid Reference series are ideal quick references, using a con-
cise,practicalapproachtoprovidesmallanimalpractitionerswithfastaccessto
essentialinformation.Designedtobeusedatapatient’sside,thesebooksmakeit
easytoquicklydiagnoseandtreatpatients.Withaspiralbindingtolieflat,Rapid
Referencebooksareanindispensabletoolfortheexamroom.
Life-Threatening
Cardiac Emergencies
for the Small Animal
Practitioner
Maureen McMichael DVM
DiplomateAmericanCollegeofVeterinaryEmergencyandCriticalCare
Professor
CollegeofVeterinaryMedicine
UniversityofIllinois
Urbana,Illinois
Ryan Fries DVM
DiplomateAmericanCollegeofVeterinaryInternalMedicine(Cardiology)
ClinicalAssistantProfessor
CollegeofVeterinaryMedicine
UniversityofIllinois
Urbana,Illinois
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LibraryofCongressCataloging-in-PublicationData
Names:McMichael,Maureen,author.|Fries,Ryan,author.
Title:Life-threateningcardiacemergenciesforthesmallanimalpractitioner/
MaureenMcMichael,RyanFries.
Othertitles:Rapidreference.
Description:Ames,Iowa:JohnWiley&Sons,Inc.,2016.|Series:Rapid
referenceseries|Includesindex.
Identifiers:LCCN2016015883(print)|LCCN2016019412(ebook)|ISBN
9781119042075(paper)|ISBN9781119042099(pdf)|ISBN9781119042082
(epub)
Subjects:|MESH:HeartDiseases–veterinary.|Emergencies–veterinary.|
Pets.
Classification:LCCSF811.M362016(print)|LCCSF811(ebook)|NLMSF811
|DDC636.089/612025–dc23
LCrecordavailableathttps://lccn.loc.gov/2016015883
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availableinelectronicbooks.
Coverimagescourtesyoftheauthors.
Setin9.5/13ptMeridienbyAptaraInc.,NewDelhi,India
1 2016
Tomymother,Ann.Youtaughtmesomuch.Iloveyouand
missyoueveryday.
M.M.
ToKatieforherloveandsupport.Tomyparentsforhelping
meachievemydreams.
R.F.
Contents
Preface,ix
Acknowledgments,xi
Introduction,xiii
1 NormalECG,1
Beforerecording,1
ECGsetup,2
RecordingtheECG,2
Whatismeasured,3
NormalECG,3
Calculatingtheheartrate,3
Calculatingthemeanelectricalaxis,5
Measuringthecomplexes,5
2 Bradyarrhythmias,8
Sinusbradycardia,8
Sinusarrhythmia,9
Sinusarrest,10
Atrialstandstill,10
AVblockoverview,12
First-degreeAVblock,12
Second-degreeAVblock,12
Third-degreeAVblock,13
Asystole,15
Cardiopulmonaryarrest,16
Escaperhythms,20
3 Tachyarrhythmias,22
Atrialprematurecomplexes,22
Ventricularprematurecomplexes,23
DifferentiatingSVTfromVT,25
Supraventriculartachycardia,27
Atrialfibrillation,29
Ventricularpre-excitation,32
Re-entranttachycardia,33
Wolff-Parkinson-Whitesyndrome,34
vii
viii Contents
Ventriculartachycardia,36
Acceleratedidioventricularrhythm,39
Ventricularflutter,40
Ventricularfibrillation,40
Torsadedepointes,41
4 Miscellaneousarrhythmiasandcardiacconditions,42
Artifactsandanomalies,42
Arrhythmogenicrightventricularcardiomyopathy,42
AVjunctionalrhythms,45
Junctionalescapebeats,45
Junctionalrhythm,46
Bradycardia-tachycardiasyndrome(sicksinussyndrome),47
Electricalalternans(pericardialeffusion),48
Leftbundlebranchblock,50
Leftanteriorfascicularblock,51
Rightbundlebranchblock,52
STsegmentabnormalities,52
Twaveabnormalities,53
Caninecongestiveheartfailure—mitralvalveinsufficiency,55
Caninedilatedcardiomyopathy,58
Felineaorticthromboembolism(saddlethrombus),61
Felinecongestiveheartfailure,64
Heartworm—cavalsyndrome(CS),68
Pericardialeffusion,73
5 ElectrolytedisturbanceandtheECG,77
Hyperkalemia,77
Hypokalemia,78
Hypercalcemia,78
Hypocalcemia,79
6 Emergencyalgorithms,80
Bradycardiaalgorithm,80
Tachycardiaalgorithm,80
Asystolealgorithm(CPR),80
Arrhythmiadrugchart,80
Furtherreading,86
Index,87
Preface
Oneofthemostfrighteningemergencypresentationsforveterinariansisthatof
apetwithalife-threateningcardiaccondition.Acatwithdullmentationanda
heart rate of 110 bpm is a critical emergency as is the dog with a heart rate of
300bpm.Thediagnosisandtreatmentoftheseanimalscannotwaitandinmany
cases treatment must be instituted before a final diagnosis is reached. Our goal
withthisbookistocreateaclear,up-to-datepracticalguidetohelpveterinarians
streamlinetheprocessoftreatingemergentcardiacpatients.Thisbookempha-
sizestheclinicalapproachinordertofacilitatearapiddiagnosisor,insomecases,
treatment before the diagnosis is made. The book is filled with numerous ECG
images,thoracicradiographs,andechocardiogramimagesaccompaniedbyclear,
concisedirectivesforemergencytreatment.
The book is separated into five sections to streamline identification: Brad-
yarrhythmias, Tachyarrhythmias, Miscellaneous arrhythmias and cardiac con-
ditions, Electrolyte disturbance and the ECG, and Algorithms and drug chart.
With a total of six chapters, four algorithms, and a drug chart, all common
life-threatening cardiac arrhythmias that occur in small animals are covered.
Additionally,inthe“Miscellaneousarrhythmiasandcardiacconditions”section,
we have added six emergency conditions that are frequently associated with
arrhythmias:Congestiveheartfailurefrommitralregurgitationindogs,conges-
tive heart failure from cardiomyopathy in cats, cardiogenic shock from dilated
cardiomyopathyindogs,arteriothromboembolismincats,cavalsyndromefrom
heartworm disease in dogs, and pericardial effusion in dogs. These were added
togivepractitionersstep-by-stepguidanceonhowtotreatthenon-arrhythmia
aspectsoftheselife-threateningemergencies.
This is a hands-on manual, very low on theory, and it is meant to be used
cage side. This book is meant for students (to streamline the material they are
learning), veterinarians in training, and veterinarians in practice who need a
quicksourcethatenablesrapiddiagnosisandtreatmentinthefaceofapetwith
adangerouscardiacarrhythmiaorcardiacemergency.
We know how frightening emergent cardiac conditions can be and we
aim to empower veterinarians with the answers in a quick and easy-to-use
format. Then, after the animal is stabilized, the theory and pathophysiology
ix
x Preface
of cardiovascular disease can be read in depth in a comfy chair by the fire.
Thereareseveralexcellenttextbooksoncardiovasculardiseasesuggestedinthe
“Furtherreading”section.
Goodluckoutthere,
Kindregards,
MaureenandRyan
Acknowledgments
Wewouldliketothankourteachersandmentorswhohavegivenusthefoun-
dation to begin learning. We thank all of the wonderful technicians we have
worked with, withoutthem we would fall apart. We also thank ourcolleagues
andreferringveterinarianswhokeepusonourtoesandpushustolearnmore
every day. Our residents are a constant source of inspiration, showing us what
can be achieved and pushing past us on this amazing road of knowledge. We
thank all of the interns and students we have worked with who show us an
unendingcuriosityandexcitementforthematerial;withoutit,wemightforget
what an amazing profession this is. We thank Wiley-Blackwell for their vision
andsupportthroughoutthisproject.Mostimportantly,wethankourclientsfor
trustinguswiththeirpreciouspets,whichteachuseverydaywhatunconditional
lovereallyis.
xi