Electrophysiologic Testing, Fifth Edition

343 Pages·2012·1.98 MB·English

by  Richard N. Fogoros(auth.)

Electrophysiologic
Testing
Electrophysiologic
Testing
FIFTHEDITION
RichardN.Fogoros,MD
Pittsburgh,PA
Thiseditionfirstpublished2012,#2012byJohnWiley&SonsLtd.
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Fogoros,RichardN.
Electrophysiologictesting/RichardN.Fogoros.–5thed.
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Includesindex.
ISBN978-0-470-67423-9(pbk.)
I. Title.
[DNLM:1. Arrhythmias,Cardiac–diagnosis.2. Arrhythmias,Cardiac–therapy.
3. ElectrophysiologicTechniques,Cardiac.WG330]
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1 2012
ToAnne,EmilyandJoe
Contents
Preface, viii
Acknowledgements, ix
PartI DisordersoftheHeartRhythm:BasicPrinciples
1 TheCardiacElectricalSystem, 3
2 AbnormalHeartRhythms, 13
3 TreatmentofArrhythmias, 23
PartII TheElectrophysiologyStudyintheEvaluation
andTherapyofCardiacArrhythmias
4 PrinciplesoftheElectrophysiologyStudy, 37
5 TheElectrophysiologyStudyintheEvaluation
ofBradycardia:TheSANode,AVNode,
andHis–PurkinjeSystem, 60
6 TheElectrophysiologyStudyintheEvaluationof
SupraventricularTachyarrhythmias, 102
7 TheElectrophysiologyStudyintheEvaluation
andTreatmentofVentricularArrhythmias, 160
8 TranscatheterAblation:Therapeutic
Electrophysiology, 210
9 CardiacResynchronization:PacingTherapy
forHeartFailure, 258
10 TheEvaluationofSyncope, 273
11 ElectrophysiologistsandDysautonomia, 285
12 ElectrophysiologicTestinginPerspective:
TheEvaluationandTreatmentof
CardiacArrhythmias, 299
Questions, 311
Answers, 323
Index, 325
vii
Preface
Thisbookalwayshasbeenaimedatdemystifyingelectrophysiology
for non-electrophysiologists who find themselves wanting to (or
perhapsmoreoften,havingto)learnsomethingaboutthisdifficult
and often intimidating field. From the beginning I wanted very
muchtowriteabookthatwasreadableandeasytounderstandfor
thestudents,residents,cardiologyfellows,cardiologists,primarycare
physicians,nurses,technicians,andothernon-electrophysiologists
whoneedasolidgroundinginthisinformationinordertodotheir
jobs well. For this work to have continued to find its intended
audiencethroughfoureditionshasbeenverygratifyingtome.
Accordingly,mychiefgoalinwritingtheFifthEditionofElectro-
physiologicTestinghasbeentoupdatewhatneededupdatingwithout
losing sight of that underlying purpose. While minor corrections
andadditionshavebeenmadethroughout,thechiefrevisionshave
beenmadeinChapters7(ventriculararrhythmias)and8(ablation
therapy), where the field has advanced significantly over the past
fewyears.Also,anewchapterhasbeenadded(Chapter11)onthe
dysautonomias—agroupofbroadlymisunderstooddisorderswhose
sufferers(likeitornot)oftenwindupthesedaysbeingreferredto
theelectrophysiologist.Thesepatientscomeinwithoutadiagnosis
andoftenwithoutmuchhope.Abasicunderstandingoftheircon-
ditionwillmakelifealoteasierforbothdoctorandpatient.
Iwouldliketothankthemanyreaderswhohavetakenthetime
toletmeknowthatthisvolumehasmadeadifferenceintheirpro-
fessional lives. Their words havemade all the effortthat has gone
intothisproject,aprojectwhichhasnowspannednearlyaquarter
century,morethanworthwhile.
viii
Acknowledgements
I would like to thank the three people from Wiley-Blackwell who
aremostresponsibleforshepherdingmethroughthisfifthedition:
Thomas Hartman, Senior Editor; Ian Collins, Senior Editorial
Assistant to Mr Hartman; and Kate Newell, Senior Developmental
Editor.
And as always, Iwantto thank my beloved wife, Anne, for her
endless patience while I worked on this book, and of course, for
toleratingalotmorebesides.
ix
I DISORDERS OF THE
HEART RHYTHM: BASIC
PRINCIPLES
ElectrophysiologicTesting,FifthEdition.RichardN.Fogoros.
(cid:2)2012JohnWiley&Sons,Ltd.Published2012byJohnWiley&Sons,Ltd.
1 The Cardiac Electrical
System
The heart spontaneously generates electrical impulses, and these
electricalimpulsesarevitaltoallcardiacfunctions.Onabasiclevel,
bycontrollingthefluxofcalciumionsacrossthecardiaccellmem-
brane, these electricalimpulses triggercardiacmuscle contraction.
On a higher level, the heart’s electrical impulses organize the
sequence of muscle contraction during each heartbeat, important
for optimizing the cardiac stroke volume. Finally, the pattern and
timing of these impulses determine the heart rhythm. Derange-
ments in this rhythm often impair the heart’s ability to pump
enoughbloodtomeetthebody’sdemands.
Thus,theheart’selectricalsystemisfundamentaltocardiacfunc-
tion.Thestudyoftheelectricalsystemoftheheartiscalledcardiac
electrophysiology, and the main concern of the field of electro-
physiologyisthemechanisms andtherapyofcardiacarrhythmias.
Theelectrophysiologystudyisthemostdefinitivemethodofevalu-
atingthecardiacelectricalsystem.Itisthesubjectofthisbook.
As an introduction to the field of electrophysiology and to the
electrophysiology study, this chapter reviews the anatomy of the
cardiac electrical system and describes how the vital electrical
impulseisnormallygeneratedandpropagated.
Theanatomyoftheheart’selectricalsystem
Theheart’selectricalimpulseoriginatesinthesinoatrial(SA)node,
located high in the right atrium near the superior vena cava. The
impulse leaves theSA node and spreads radially across both atria.
When the impulse reaches the atrioventricular (AV) groove, it
encounters the “skeleton of the heart,” the fibrous structure to
which the valve rings are attached, and which separates the atria
from the ventricles. This fibrous structure is electrically inert and
acts as an insulator—the electrical impulse cannot cross this
ElectrophysiologicTesting,FifthEdition.RichardN.Fogoros.
(cid:2)2012JohnWiley&Sons,Ltd.Published2012byJohnWiley&Sons,Ltd.
3
DISORDERSOFTHEHEARTRHYTHM:BASICPRINCIPLES
structure. Thus the electrical impulse would be prevented from
crossingovertotheventricularsideoftheAVgrooveifnotforthe
specialized AV conducting tissues: the AV node and the bundle of
His(Figure1.1).
As the electrical impulse enters the AV node, its conduction is
slowedbecauseoftheelectrophysiologicpropertiesoftheAVnodal
tissue. This slowing is reflected in the PR interval on the surface
electrocardiogram (ECG). Leaving the AV node, the electrical
impulseenterstheHisbundle,themostproximalpartoftherapidly
conducting His–Purkinje system. The His bundle penetrates the
fibrousskeletonanddeliverstheimpulsetotheventricularsideof
theAVgroove.
Once on the ventricular side, the electrical impulse follows the
His bundle as it branches into the right and left bundle branches.
Figure1.1 Anatomyoftheelectricalsystemoftheheart.
4