PACES/HRS Expert Consensus Statement on the Recognition and Management of Arrhythmias in ...

63 Pages·2014·2.81 MB·English

CanadianJournalofCardiology30(2014)e1ee63
Society Guidelines
PACES/HRS Expert Consensus Statement on the
Recognition and Management of Arrhythmias in Adult
Congenital Heart Disease
Developed in Partnership Between the Pediatric and Congenital
Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS).
Endorsed by the Governing Bodies of PACES, HRS, the American College of
Cardiology (ACC), the American Heart Association (AHA), the European Heart
Rhythm Association (EHRA), the Canadian Heart Rhythm Society (CHRS), and the
International Society for Adult Congenital Heart Disease (ISACHD)
y
Paul Khairy, MD, PhD, FRCPC (Chair),* George F. Van Hare, MD, FACC, FHRS (Co-Chair),
y y z
Seshadri Balaji, MBBS, PhD, Charles I. Berul, MD, FHRS, Frank Cecchin, MD, FACC,
y
Mitchell I. Cohen, MD, FACC, FHRS, Curt J. Daniels, MD, FACC,**
y {
Barbara J. Deal, MD, FACC, Joseph A. Dearani, MD, FACC,* Natasja de Groot, MD, PhD,
Anne M. Dubin, MD, FHRS,y Louise Harris, MBChB, FHRS,# Jan Janousek, MD, PhD,{
y y
Ronald J. Kanter, MD, FHRS, Peter P. Karpawich, MD, FACC, FAHA, FHRS,
y
James C. Perry, MD, FACC, FHRS,* Stephen P. Seslar, MD, PhD,
y x
Maully J. Shah, MBBS, FHRS, Michael J. Silka, MD, FACC, FAHA,
y y
John K. Triedman, MD, FACC, FHRS, Edward P. Walsh, MD, FACC, FHRS, and
Carole A. Warnes, MD, FRCP, FACC, FAHA**
*PediatricandCongenitalElectrophysiologySociety(PACES)representative;yHeartRhythmSociety(HRS)representative;zAmericanCollegeofCardiology(ACC)
representative;xAmericanHeartAssociation(AHA)representative;{EuropeanHeartRhythmAssociation(EHRA)representative;#CanadianHeartRhythmSociety(CHRS)
representative;**InternationalSocietyforAdultCongenitalHeartDisease(ISACHD)representative
TABLE OF CONTENTS
Preamble e2 3.4. Systemic right ventricle and univentricular
heart e5
1. Methodology and Evidence e3
4. DeliveryofCareandEnsuringAccesstoCare e6
2. Document Review and Approval e3
4.1. Recommendations for the coordination and de-
3. Epidemiology andScope ofArrhythmiasinAdults
livery of care for adults with CHD and
With CHD e4
arrhythmias e6
3.1. Changing mortality e4
4.2. Recommendations for adults with CHD
requiring invasive electrophysiologic
3.2. Spectrum of arrhythmias e4
interventions e7
3.3. Heart failure and arrhythmogenesis e4
5. Evaluation and Diagnosis of Arrhythmias e8
5.1. Introduction e8
Correspondingauthor:DrPaulKhairy,AdultCongenitalHeartCenter,MontrealHeartInstitute,5000BelangerSt.E.,Montreal,QuebecH1T-1C8,Canada.
E-mail:[email protected]
http://dx.doi.org/10.1016/j.cjca.2014.09.002
0828-282X/(cid:1)2014HeartRhythmSociety.Allrightsreserved.
e2 CanadianJournalofCardiology
Volume302014
5.2. General rhythm assessment based on cardiac 9.2. Sudden and total late mortality e26
history and symptom status e8
9.3. Arrhythmic causes of sudden cardiac death e27
5.3. Approach to the symptomatic patient e8
9.4. Recommendations for ICD therapy in adults
5.4. Approach to the asymptomatic patient e11 with CHD e28
6. Medical Therapy e12 9.5. Unique considerations for ICDs e29
6.1. Atrial tachyarrhythmias e12 9.6. Results and outcomes of ICD therapy e29
6.2. Ventricular tachyarrhythmias e17 9.7. Considerations regarding ICD programming e30
7. Catheter Ablation e18 10. Cardiac resynchronization therapy e30
7.1. General considerations for catheter ablation in 10.1. Dyssynchronous heart failure e30
adults with CHD e18
10.2. Clinical studies on CRT in CHD e31
7.2. AV reciprocating tachycardia and AV nodal
10.3. Technical aspects e33
reentrant tachycardia e18
10.4. Recommendations e33
7.3. Atrial tachyarrhythmias e19
7.4. Atrial fibrillation e20 11. Surgical options e33
11.1. Introduction e33
7.5. Recommendations for catheter ablation of atrial
tachycarrhythmias in adults with CHD e20 11.2. Preoperative arrhythmia evaluation e34
7.6. Ventricular tachycardia e21 11.3. Recommendations for electrophysiologic study
prior to adult CHD surgery e36
8. Bradyarrhythmias and Pacemakers e22
11.4. Role of surgery in treating preexisting
8.1. Introduction e22
arrhythmias e36
8.2. Sinus node dysfunction e22
11.5. Recommendations for concomitant ventricular
8.3. AV conduction system dysfunction e23 arrhythmia surgery in adults with CHD un-
dergoing open cardiac surgery e38
8.4. Preimplant considerations e24
11.6. The role of surgery in preventing the develop-
8.5. Issues related to specific congenital heart
ment of arrhythmias e38
defects e25
11.7. Recommendations for prophylactic atrial or
8.6. Lead extraction e25
ventricular arrhythmia surgery in adults with
8.7. Recommendations for permanent pacing in CHD e39
adults with CHD e26
Appendix 1 e39
9. Sudden Cardiac Death and ICDs e26
References e39
9.1. Introduction e26
Preamble inconsequentialandbenigntopoorlytoleratedandpotentially
Nearlyonethirdofallmajorcongenitalanomaliesareheart fatal. Taken together, arrhythmias are a leading cause of
defects, with an estimated 9 per 1000 live births afflicted by morbidity, impaired quality of life, and mortality in adults
congenital heart disease (CHD) worldwide.1 Remarkable ad- with CHD.
vances in care have resulted in impressive gains in survival Inlightoftheuniqueissues,challenges,andconsiderations
such that over 90% of children with CHD in developed involvedinmanagingarrhythmiasinthisgrowing,aging,and
countries today are expected to survive into adulthood.2 heterogeneouspatientpopulation,7itappearsbothtimelyand
Consequently, the past decades have witnessed historical essential to critically appraise and synthesize optimal treat-
shifts in population demographics, as adults now outnumber ment strategies. The purpose of this consensus statement is,
childrenwithCHD. Population-basedestimatesindicatethat therefore,todefineoptimalconditionsforthedeliveryofcare
there are currently over 1 million adults with CHD in the regardingarrhythmiasinadultswithCHDandprovideexpert
UnitedStatesalone,over100,000inCanada,and1.8million and,wherepossible,evidence-basedrecommendationsonbest
in Europe.3-5 Rhythm disorders, which span the entire spec- practice procedures for the evaluation, diagnosis, and man-
trum of brady- and tachyarrhythmias, are among the most agement of arrhythmias, including medical treatment,
prominent complications encountered by adults with CHD.6 catheter-based interventions, device therapy, and surgical
Arrhythmias range in symptomatology and significance, from options.
Khairyetal. e3
PACES/HRSExpertConsensusStatementonArrhythmiasinAdultCongenitalHeartDisease
Table1.1. ClassificationofCHDcomplexityinadults electrophysiology, adult CHD, and CHD surgery. The
writing committee included representation from the Amer-
Typeofcongenitalheartdiseaseintheadult
Complexity patients ican College of Cardiology (ACC), American Heart Associ-
ation(AHA),EuropeanHeartRhythmAssociation(EHRA),
Simple Nativedisease
Isolatedcongenitalaorticvalve CanadianHeartRhythmSociety(CHRS),andInternational
disease SocietyforAdultCongenitalHeartDisease(ISACHD).The
Isolatedcongenitalmitralvalvedisease(except committee was divided into subgroups to review key aspects
parachutevalve,cleftleaflet)
intherecognitionandmanagementofarrhythmiasinadults
Smallatrialseptaldefect
Isolatedsmallventricularseptaldefect(no with CHD. Experts in the topics under consideration were
associatedlesions) tasked with performing formal literature reviews, weighing
Mildpulmonarystenosis the strength of evidence for or against diagnostic and ther-
Smallpatentductusarteriosus apeutic interventions, estimating expected health outcomes
Repairedconditions
where relevant, and proposing practical clinical recommen-
Previouslyligatedoroccludedductusarteriosus
Repairedsecundumorsinusvenosusatrialseptal dations. Wherever possible, recommendations are evidence-
defectwithoutresidua based. However, unlike some practice guidelines, there is
Repairedventricularseptaldefectwithoutresidua not a sizeable body of literature with definitive evidence to
Moderate Aorto-leftventricularfistulas support most recommendations in this emerging field of
Anomalouspulmonaryvenousdrainage,partialor
total cardiology.Inordertomaximizethevalueandcredibilityof
Atrioventricularseptaldefects,partialorcomplete consensus-based recommendations, a high-threshold (i.e.,
Coarctationoftheaorta 80% or greater agreement among writing members) was
Ebsteinanomaly
required to constitute a consensus. Supportive evidence is
Infundibularrightventricularoutflowobstruction
ofsignificance indicated where appropriate, and variations in opinion are
Ostiumprimumatrialseptaldefect nuanced in the text. As a general recommendation, the
Patentductusarteriosus,notclosed committee strongly supports expanding the evidence base
Pulmonaryvalveregurgitation,moderatetosevere related to arrhythmias in adults with CHD through partic-
Pulmonaryvalvestenosis,moderatetosevere
SinusofValsalvafistula/aneurysm ipation in research and clinical registries.
The consensus statement was organized by arrhythmia-
Sinusvenosusatrialseptaldefect
Subvalvularorsupravalvularaorticstenosis related topics rather than by heart defect. Depending, in
TetralogyofFallot part, on the particular issue and available evidence, rec-
Ventricularseptaldefectwith: ommendations range from being broadly applicable to
Absentvalveorvalves adults with CHD at large to a more focused lesion-specific
Aorticregurgitation
Coarctationoftheaorta scope. The detailed index should assist the reader in
Mitraldisease rapidly locating sections of interest for specific heart de-
Rightventricularoutflowtractobstruction fects. In addition, the writing committee retained the
Straddlingtricuspidormitralvalve
nomenclature for complexity of CHD (i.e., simple, mod-
Subaorticstenosis
Severe/complex Conduits,valvedornonvalved erate, complex/severe) proposed by the ACC/AHA task
Cyanoticcongenitalheartdisease,allforms force on practice guidelines for adults with CHD,8 sum-
Double-outletventricle marized in Table 1.1.
Eisenmengersyndrome Recommendations were subject to a previously described
Fontanprocedure standardized classification process (Methodology Manual and
Mitralatresia
Singleventricle(alsocalleddoubleinletoroutlet, Policies from the ACCHF and AHA Task Force on Practice
common,orprimitive)Pulmonaryatresia,all Guidelines June 2010)9 that ranked each item (Classes I, IIa,
forms IIb, III) and its accompanying level of evidence (Levels A, B,
Pulmonaryvascularobstructive
C), as summarized in Table 1.2.
disease
Transpositionofthegreatarteries
Tricuspidatresia
Truncusarteriosus/hemitruncus
Otherabnormalitiesofatrioventricularor 2. Document Review and Approval
ventriculoarterialconnectionnotincludedabove
The PACES/HRS Task Force made every effort to
(e.g.,crisscrossheart,isomerism,heterotaxy
syndromes,ventricularinversion) avoid all potential conflicts of interest relevant to this
consensus statement, whether actual or perceived, among
Adapted from Warnes CA, et al. ACC/AHA 2008 guidelines for the
members of the writing committee. Members of the
management of adults with congenital heart disease. J Am Coll Cardiol.
2008;52:1890-1947.8 writing committee (Appendix 1) and peer reviewers
(Appendix 2) were required to disclose all actual or po-
tential direct or indirect conflicts. Committee members
1. Methodology and Evidence were obliged to refrain from voting on issues related to
The Pediatric and Congenital Electrophysiology Society the potential conflict. The document was reviewed by the
(PACES), in conjunction with the Heart Rhythm Society PACES executive committee, additional members of
(HRS), appointed a 22-member writing committee from HRS, and official reviewers nominated by ACC, AHA,
the United States, Canada, and Europe with complemen- EHRA, CHRS, and ISACHD. All writing members
tary multidisciplinary expertise in pediatric and adult approved this final version.
e4 CanadianJournalofCardiology
Volume302014
3. Epidemiology and Scope of Arrhythmias in Table1.2. Classificationofrecommendationsandlevelsofevidence9
Adults With CHD ClassificationofRecommendations
3.1. Changing mortality ClassI Conditionsforwhichthereisevidence
and/orgeneralagreementthata
The advent of cardiopulmonary bypass and early surgical givenprocedureortreatmentplanis
innovations for CHD of the 1960s and 1970s, coupled with beneficial,useful,andeffective
ClassII Conditionsforwhichthereis
advancesinclinicalcare,haveculminatedinanincreasingand conflictingevidenceand/or
aging cohort with CHD.10 Survival beyond the first year of divergenceofopinionaboutthe
life has risen from an estimated 25% 50 years ago to >90% usefulness/efficacyofaprocedureor
expected survival into adulthood.11,12 In a population-based treatment
ClassIIa Weightofevidence/opinionisinfavor
cohort study of patients with CHD, an overall mortality
ofusefulness/efficacy
reduction of 31% was observed from 1987 to 2005, largely ClassIIb Usefulness/efficacyislesswell
driven by improved survival in infants.2 Most notably, the establishedbyevidence/opinion
median age of death in patients with severe forms of CHD ClassIII Conditionsforwhichthereis
increased from 2 to 23 years of age. The older adult with conflictingevidenceand/orgeneral
agreementthataprocedureor
CHDcanalsoanticipateaconsiderablylongerlifeexpectancy,
treatmentisnotuseful/effectiveand
withonestudyreportingamedianageatdeathof57yearsin insomecasesmaybeharmful
2007 compared to 37 years in 2002.13 Although causes of LevelsofEvidence
deathappeartohaveremainedmoreorlessconsistentoverthe LevelofevidenceA Dataderivedfrommultiple
pasttwodecades,recentyearshaveseenashiftintheprofileof randomizedclinicaltrialsormeta-
analyses
thepatientatrisk.Whilelesionseverityandsurgicalresultsare
LevelofevidenceB Dataderivedfromasinglerandomized
majordeterminantsofoutcomeininfantsandchildren,heart trialornonrandomizedstudies
failure, arrhythmias, and pulmonary hypertension become LevelofevidenceC Onlyconsensusopinionofexperts,
increasingly important in adulthood. Additional prognostic casestudies,orstandardofcare
factors in older patients include systemic ventricular
dysfunction, chronic renal disease, coronary artery disease,
malignancies, and conventional risk factors such as diabetes, A tabular representation of approximate expected risks for
hypertension, and obesity.10,14,15 atrial arrhythmia, ventricular arrhythmia, AV block, and
ventricular dyssynchrony are summarized in Figure 3.2. The
prevalence and mechanism of arrhythmias vary according to
factors such as age, underlying anatomic defect, and method
3.2. Spectrum of arrhythmias
of surgical repair.31 For example, while 3%-5% of patients
Arrhythmias increase in prevalence as adults with CHD with congenitally corrected transposition will be born with
age and are the most frequent reason for hospital admis- completeAVblock,itisestimatedthatanadditional20%will
sion.16,17Alongwithheartfailure,arrhythmiasaretheleading develop complete heart block by adulthood.35,36 For others,
cause of death.18-21 Factors associated with pre- and post- prior surgery in the region of the sinus node or its arterial
operative arrhythmias in CHD are schematically depicted in supply (e.g., Mustard, Senning, Glenn, or Fontan) will leave
Figure 3.1.22 Arrhythmias may reflect congenitally displaced them predisposed to later sinus node dysfunction.32,37,38
ormalformedsinusnodesoratrioventricular(AV)conduction
systems, abnormal hemodynamics, primary myocardial dis-
3.3. Heart failure and arrhythmogenesis
ease, hypoxic tissue injury, residual or postoperative sequelae,
and genetic influences.23-25 The relationship of heart failure to arrhythmogenesis and
Theentirespectrumofarrhythmiasmaybeencounteredin sudden cardiac death risk is increasingly appreciated.22 He-
adults with CHD, with several subtypes often coexisting. modynamic and electrophysiologic conditions that lead to
Bradyarrhythmiasmayinvolvedisordersofthesinusnode,AV heart failure, clinical arrhythmias, and adverse outcomes in
node,HisePurkinjesystem,orintra-atrialpropagation.Ithas adults with CHD often extend over several decades. These
been estimated that approximately 50% of 20-year-olds with include long-standing effects of prior atrial or ventricular
CHD will develop an atrial tachyarrhythmia during their volumeloading,scarring,patches,bafflesandsurgicalbarriers,
lifetime.26 Table 3.1 summarizes atrial tachyarrhythmias electromechanical dyssynchrony, ongoing deleterious effects
typically encountered in common forms of CHD.27 Atrial on cellecell electrical coupling, and underlying genetic as-
tachyarrhythmiasmaybemediatedbyaccessorypathways,AV pects. Inevitably, the incidence of arrhythmias in the adult
node reentry, twin AV nodes,28,29 macroreentrant circuits, CHD population far exceeds that seen in younger patients.
automatic foci, or nonautomatic foci.30 Intra-atrial reentry is Unique forms of heart failure can also be encountered,
themostcommontachyarrhythmiainadultswithCHD,31-33 including dysfunction of a systemic right ventricle or uni-
although the prevalence of atrial fibrillation is on the rise as ventricular heart. Systemic left ventricular failure is often
the population ages.31,34 Ventricular arrhythmias are thought associated with congenital left-sided cardiac lesions. Left
tobetheleadingcauseofsuddendeathinseveralsubtypesof ventricular dysfunction in tetralogy of Fallot and Ebstein
CHD, with an overall risk that is up to 100-fold higher than malformationofthetricuspidvalveismorewidelyappreciated
in age-matched controls.18,19 Fortunately, the absolute inci- asasequelaassociatedwithheightenedriskforsuddencardiac
dence of these devastating events remains relatively low, at death.31,39-41 Righteleft ventricular interactions are increas-
approximately 0.1% per year. ingly acknowledged, and subpulmonary right ventricular
Khairyetal. e5
PACES/HRSExpertConsensusStatementonArrhythmiasinAdultCongenitalHeartDisease
Figure3.1 Schematicoffactorsleadingtoarrhythmiasin(A)pre-and(B)postoperativecongenitalheartdisease.AV¼atrioventricular.(Repro-
ducedwithpermissionfromEscuderoC,etal.Electrophysiologicconsiderationsincongenitalheartdiseaseandtheirrelationshiptoheartfailure.
CanJCardiol2013;29(7):821-829.22)
failure itself contributes to the complex interplay of factors
associated with sudden death.42,43 Ventricular dyssynchrony Table3.1. Summaryofatrialtachyarrhythmiasencounteredin
commonformsofCHD
due to intrinsic or pacing-induced ventricular conduction
delay can likewise have deleterious effects on systemic ven- Congenitalheartdiseasetype Tachyarrhythmia
tricular function. In adults with CHD, right bundle branch
Atrialseptaldefect IART/AFwithincreasingage,
block(RBBB)ismorecommonthanleftbundlebranchblock particularlyiflateclosure
(LBBB), particularly in the setting of tetralogy of Fallot, Atrioventricularseptaldefect IART/AFfollowingsurgicalrepair
ventricular septal defects, double-outlet right ventricle vari- Ebsteinanomaly IART;AVoratriofascicular(Mahaim)
AP;suddendeathifhighriskor
ants, Rastelli surgery, AV septal defects, and Ebstein malfor-
multipleAPs;ectopicatrial
mation of the tricuspid valve. In most cases, RBBB is a tachycardia;AF
complication of surgical repair. Left-sidedobstructivelesions IART/AF
TGAwithintraatrialbaffle IART,NAFAT,AVNRT;VT/VFmay
besecondarytoatrialarrhythmias
3.4. Systemic right ventricle and univentricular heart
CongenitallycorrectedTGA AccessorypathwayifEbstein-like
Adults with systemic right ventricles and atrial switch sur- systemicAVvalve
TetralogyofFallot IART;NAFATalongtheanterolateral
gery (e.g., Mustard or Senning) have extensive atrial scarring,
rightatrium
with a high incidence of atrial tachyarrhythmias.44 Rapid AV Heterotaxysyndrome TwinAVnode-mediatedreentrant
conduction in the setting of an already compromised systemic tachycardia
rightventriclecanresultininductionofasecondaryventricular SingleventriclewithFontan IART;NAFAT;AF;maybepoorly
tachycardia.45,46 Primary ventricular arrhythmias may also tolerated
Eisenmengerphysiology MAT;IART;AF
occur,mostofteninassociationwithsystemicrightventricular
failure.36,46-48 Myocardial oxygen supplyedemand mismatch AF ¼atrial fibrillation;AP¼accessory pathway;AV ¼atrioventric-
can increase over time, leading to ongoing fibrosis, worsening ular; AVNRT ¼ AV nodal reentrant tachycardia; IART ¼ intraatrial
reentrant tachycardia; MAT ¼ multifocal atrial tachycardia; NAFAT ¼
systemic ventricular function, and accrued risk of sudden
nonautomatic focal atrial tachycardia; TGA ¼ transposition of the great
death.49 Adults with single ventricle physiology and Fontan arteries; VF ¼ ventricular fibrillation; VT ¼ ventricular tachycardia.
palliationarealsoatriskfordevelopingsinusnodedysfunction
Adapted with permission from Khairy P. In: Shenasa M et al (eds).
andatrialtachyarrhythmias.50,51Atrialarrhythmiasoccurinup Cardiac Mapping. Fourth Edition. Oxford, UK: Wiley-Blackwell;
to60%ofFontanrecipientsandareassociatedwithsubstantial 2013:771-777.27
e6 CanadianJournalofCardiology
Volume302014
Figure3.2 Approximateriskestimatesforatrialtachycardia(AT),atrialfibrillation(AF),othersupraventriculararrhythmias,ventriculararrhythmia,sinusnode
dysfunction(SND),atrioventricular(AV)block,andventriculardyssynchronyareshownacrossvariouscongenitalheartdefects(CHD)ofsimple,moderate,and
severecomplexity.Thecolor-codedpatternrangesfromminimal(noshading)tomild(lightblue),moderate(mediumblue),andhigh(darkblue)risk.
morbidity and mortality.52 Approximately 90% of Fontan The 32nd Bethesda Conference report called attention to
patients with heart failureerelated deaths have concomitant the need for health care professionals, patients and their
atrial tachyarrhythmias.51 families,andregulatoryagenciestodevelopastrategicplanto
improve care access and delivery to the adult with CHD.53
Recognition and management of arrhythmias is an integral
4. DeliveryofCareandEnsuringAccesstoCare component of such specialized care.18,19,24,58 Coordinating
care across subspecialties and the development of training
4.1.Recommendationsforthecoordinationanddelivery
programs specific to arrhythmias in adults with CHD are
of care for adults with CHD and arrhythmias
consideredkeyfactorsinensuringaccessanddeliveryofhigh-
Recommendations quality care. Health care needs, particularly for adults with
moderateandcomplexformsofCHD,shouldbecoordinated
ClassI 1. HealthcareforadultswithCHDandarrhythmiasshouldbe
coordinatedbyregionaladultCHD(ACHD)centersof byregionalACHDcentersofexcellence.8,54,59Personneland
excellencethatservethesurroundingmedicalcommunityasa services previously recommended for regional ACHD centers
resourceforconsultationandreferral(Levelofevidence:C).53 are summarized in Table 4.1.8
2. AregionalACHDcenterthatcaresforadultswithCHDand
Becausearrhythmiasaccountforthemajorityofemergency
arrhythmiasshouldbestaffedbyatleastonecardiacelectro-
physiologistwithexpertiseinCHD,inadditiontoassociated room visits in adults with CHD, emergency care facilities
CHDsubspecialistsinimaging,interventionalcardiology,and shouldideallyhaveaccessto,andanaffiliationwith,aregional
cardiacsurgery(Levelofevidence:C).8,54,55 ACHD center.60 The provision of support for local emer-
3. Diagnostic and interventional catheter- and device-based
gency centers is critically important considering that these
electrophysiologicproceduresinadultswithmoderateor
centers may have little or no familiarity with CHD anatomy,
complexCHDorcomplexarrhythmiasshouldbeperformedin
aregionalACHDcenterbyacardiacelectrophysiologistwith hemodynamics, and complex management issues.61 In other
expertiseinCHD,andinalaboratorywithappropriate less urgent situations, coordination by a regional ACHD
personnelandequipment(Levelofevidence:C).7,56,57 center should include the availability of consultation services
Khairyetal. e7
PACES/HRSExpertConsensusStatementonArrhythmiasinAdultCongenitalHeartDisease
Table4.1. PersonnelandservicesrecommendedforregionalACHD including interventional cardiologists, heart failure specialists,
centers and/oradultCHDsurgeons.Examplesincludehybridsurgical
Typeofservice Personnel/resources approaches to managing arrhythmias,66 recanalization of
obstructedbafflesorconduitstoallowcatheterorleadaccess,67
CardiologistspecializinginACHD Oneorseveral24/7
Congenitalcardiacsurgeon Twoorseveral24/7 presurgical electrophysiologic mapping, epicardial lead im-
Nurse/physicianassistant/nurse Oneorseveral plantation,7 and arrhythmia surgery (see Section 11).
practitioner
Cardiacanaesthesiologist Several24/7
Echocardiography* Twoorseveral24/7
(cid:2) IncludesTEE,intraoperativeTEE 4.2. Recommendations for adults with CHD requiring
Diagnosticcatheterization* Yes,24/7 invasive electrophysiologic interventions
Noncoronaryinterventional Yes,24/7
Recommendations
catheterization*
Electrophysiology/pacing/ICD Oneorseveral ClassI 1. Consultation with an ACHD specialist should be
implantation* soughtpriortoinvasiveelectrophysiologicinterventions
Exercisetesting inadultswithCHD(Levelofevidence:C).8,54,55
(cid:2) Echocardiography 2. Preproceduralplanningshouldincludeadetailedreview
(cid:2) Radionuclide ofoperativenotespertainingtoallpreviouscardiacand
(cid:2) Cardiopulmonary vascularsurgeries,patientanatomy,vascularandintra-
(cid:2) Metabolic cardiacaccessissues,priorinterventions,andalldocu-
Cardiacimaging/radiology* mentedarrhythmias(Levelofevidence:C).6,7,68
(cid:2) CardiacMRI 3. Invasiveelectrophysiologicinterventionsinadultswith
(cid:2) CTscanning moderateorcomplexCHDthatrequireconscious
(cid:2) Nuclearmedicine sedationorgeneralanesthesiashouldbeperformedin
Multidisciplinaryteams (cid:2) High-riskobstetrics collaborationwithananesthesiologistfamiliarwith
(cid:2) Pulmonaryhypertension CHD(Levelofevidence:C).69
(cid:2) Heartfailure/transplant 4. The electrophysiology laboratory and postprocedure
(cid:2) Genetics recoveryunitshouldbesuitableforthecareofadults
(cid:2) Neurology withCHD,including:
(cid:2) Nephrology 1. Adultappropriateequipment(Levelofevidence:C);
(cid:2) Cardiacpathology 2. Nursingandtechnicalstaffcertifiedinadultcardiac
(cid:2) Rehabilitationservices lifesupport(ACLS)andtrainedinbasicCHD
(cid:2) Socialservices anatomy(Levelofevidence:C);
(cid:2) Vocationalservices 3. ACHD cardiothoracic surgical backup and oper-
(cid:2) Financialcounselors atingroomaccess(Levelofevidence:C).70
Informationtechnology
(cid:2) Databasecollection
(cid:2) Databasesupport
(cid:2) Qualityassessment
Invasive electrophysiologic procedures in adults with
review/protocols
CHD should be performed by electrophysiologists with
Reproduced with permission from Warnes CA, et al. ACC/AHA 2008
expertise in adults with CHD and within an environment
guidelinesforthemanagementofadultswithcongenitalheartdisease.JAm
CollCardiol2008;52:1890-1947.8 suitableforCHDandadultpatientcare.59Thetechnicaland
24/7¼availability24hoursperday¼7daysperweek;ACHD¼adult nursing staff involved with preprocedural, procedural, and
congenitalheartdisease;CT¼computedtomography;ICD¼implantable postproceduralcaremustbeACLScertifiedandfamiliarwith
cardioverter-defibrillator; MRI ¼ magnetic resonance imaging; TEE ¼
transesophagealechocardiography.
*These modalities must be supervised/performed and interpreted by
Table4.2. Basicrequirementsforelectrophysiologistswithexpertise
physicianswithexpertiseandtrainingincongenitalheartdisease.
inadultCHD
Completionofspecializedfellowshiptraininginadultorpediatricelectrophysiology
withdemonstratedacquisitionofrequiredclinicalcompetencies62-65
for arrhythmia-related issues, with consideration given to FormalaffiliationwithanestablishedACHDcenter8,64
Fundamentalknowledgeofcongenitalheartdisease,including:
transferring care whenever subspecialtyexpertise are required, (cid:2) Anatomyandphysiologyofsimple,moderate,andcomplex
including for electrophysiologic studies, catheter ablation, or formsofcongenitalheartdisease
device implantation.8 (cid:2) Surgicalproceduresforcongenitalheartdisease
Although detailed recommendations regarding training and (cid:2) Naturalandunnatural(postsurgical)short-andlong-term
arrhythmiasequelae
skillsrequiredtoqualifyasanelectrophysiologistwithexpertise
(cid:2) Particularitiesessentialtosafelyandeffectivelyexecutearrhythmia
in adult CHD are beyond the scope of this consensus docu-
interventions,includinganappreciationforcomplexaccessissuesand
ment, basic competencies are summarized in Table 4.2.62-65 displacedormalformedatrioventricularconductionsystems6,7,68
Currently, there is a paucity of formally trained adult CHD Experienceandskillsinmanagingadultswithcongenitalheartdiseaseand
electrophysiologists, and, therefore, close collaborations be- arrhythmias,64including:
(cid:2) Noninvasivetesting
tween adult and pediatric electrophysiologists and ACHD (cid:2) Electrophysiologicstudies
specialistsmayberequiredtodeliverhigh-qualitycaretoadults (cid:2) Catheterablation,includingwith3-dimensionalelectroanatomic
withCHDandarrhythmias.Thesearrangementsareviewedby mappingsystemsandlarge-tip/irrigatedcatheters
the committee as acceptable methods of optimizing quality of (cid:2) Intraoperativeprocedures
(cid:2) Cardiacrhythmmanagementdevices
care. In certain circumstances, a broader team approach to
managingadultswithCHDandarrhythmiasmaybebeneficial, ACHD¼adultcongenitalheartdisease.
e8 CanadianJournalofCardiology
Volume302014
basic CHD anatomy and physiology. Preprocedural evalua- 5.3. Approach to the symptomatic patient
tion may include risk analysis that considers associated
Carefulhistoryandphysicalexaminationrevealamixofelec-
comorbidities, additional subspecialty consultation (e.g., pul-
trophysiologicandhemodynamicdatathatarevitaltodetermining
monary medicine, nephrology, infectious disease), anesthesia
thepaceandsettingofthesubsequentevaluation.Attributesofthe
assessment, and supplementary preprocedural imaging or
symptoms,includingtiming,duration,context,andseverity,are
functional analysis, as needed.
helpfulinguidingthesubsequentselectionoftests.Inpatientswith
aninsitucardiacrhythmmanagementdevice,deviceinterrogation
5. Evaluation and Diagnosis of Arrhythmias mayprovidetherequiredinformationtoclinchadiagnosis.75In
the absence of such a device or in the event of an unrevealing
5.1. Introduction
interrogation,subsequentworkupisdeterminedbasedonlevelof
Arrhythmias and their attendant clinical consequences cliniciansuspicionandseverityofsymptoms.
becomeincreasinglyprevalentinadultswithCHDastheyage. In patients with aborted sudden cardiac death or unex-
Ramifications are often dependent as much on the clinical plainedsyncope,considerationshouldbegiventoperforminga
contextinwhichthearrhythmiaoccursasthearrhythmiaitself. diagnosticelectrophysiologicstudywithprogrammedatrialand
Forthatreason,thissectionstressestheimportancenotonlyof ventricularstimulation.75,76Formildersymptoms,someform
electrophysiologic testing from which one might elucidate the of ambulatory monitoring is usually indicated. Frequent or
correct “electrical” diagnosis but also of a broader evaluation incessantsymptomsmaybewellsuitedfor24-hourambulatory
thatallowscareproviderstounderstandthearrhythmiawithin ECG(Holter)evaluation.Incontrast,infrequent,briefsymp-
thecontextofthepatient’scardiovascularstatus.Althoughitis toms are better evaluated using an event recorder or longer-
possible to make some generic recommendations regarding durationHoltermonitoring.Whilepursuingtheelectrophysi-
adults with CHD as a collective entity or within defined sub- ologic evaluation, the clinician must also assess the patient’s
groups, in many cases, the natural and modified history of anatomyandhemodynamic/functionalstatus.Criticalparam-
specific anatomic forms of CHD and/or associated palliative etersincludeventricularsizeandfunction,AVvalvefunction,
corrections dictate more precise targeting of recommendations andvesselorbafflepatency,whichcanoftenbeelucidatedby
to specific substrates. Finally, although the presence of symp- transthoracic echocardiography. When relevant, additional
toms will drive the majority of arrhythmia evaluations, it is functional and anatomic data can be obtained through 3-
recognizedthatsurveillancetestinginselectcircumstancesmay dimentional imaging such as cardiac computed tomography
alerttheprovidertoanimpendingorunrecognizedarrhythmia. (CT)ormagneticresonanceimaging(MRI),ormoreinvasive
means such as transesophageal echocardiography or cardiac
5.2.Generalrhythmassessmentbasedoncardiachistory catheterization. Like history and physical examination, ECG
and symptom status andcardiopulmonaryexercisetestingprovideavaluablemixof
bothelectrophysiologicandhemodynamic/functionaldata.
ArrhythmiarisksinadultswithCHDvaryaccordingtothe
underlying heart lesion, hemodynamics, and features in a pa-
tient’sclinicalhistory.Certainrhythmdisordersarewellknown 5.3.1. Rhythm testing for symptomatic patients
to be lesion-specific, such as accessory pathwayemediated
5.3.1.1. Electrocardiogram. Documentation of an active
tachycardiainEbsteinanomaly71andAVblockinthesettingof
arrhythmia by 12-lead ECG at the time of symptoms is a
L-loopedtranspositionofthegreatarteries.72Thetendencyfor cornerstone of diagnosis, but this luxury is not always avail-
atrialtachycardiasandsinusnodedysfunctiontodevelopinpa-
able. Observations such as marked bradycardia, AV and
tientswhohaveundergoneextensiveatrialbafflingproceduresis
intraventricular conduction disturbances, QRS duration,
alsoclearlyestablished,32,73asistheassociationofmonomorphic
repolarization pattern, and varied degrees of atrial and ven-
ventricular tachycardia with such lesions as surgically repaired
tricular ectopic activity may all prove useful in deciphering a
tetralogyofFallot,31andpolymorphicventriculartachycardiaor patient’s complaint. Typical ECG features in adults with
ventricularfibrillationinpatientswithadvanceddegreesofven- common forms of CHD are summarized in Table 5.1.77
triculardysfunction.40,74Moreover,lateageattimeofcomplete
surgicalrepairandincompleteorimperfectrepairwithresidual 5.3.1.2. Ambulatory ECG (Holter monitoring and event record-
cyanosisorpressure/volumeloadsareamongthemanyhistorical ers). Indications for ambulatory monitoring and selection of
itemsthathavebeenimplicatedasgeneralriskfactorsforboth recording technique in symptomatic patients with CHD are
atrial and ventricular arrhythmias. Individual patient anatomy, similartothoseforthegeneralpopulation.78StandardHolter
surgical history, and hemodynamic status must, therefore, be monitoringisbestsuitedfortheevaluationofdailysymptoms
ascertainedfullywheneverarrhythmiarisksarebeingestimated. or arrhythmias. The yield in evaluating sporadic symptoms
Thepresenceorabsenceofsymptomsisapracticalstarting such as syncope is generally low.79,80 More recently, devices
point for evaluating adults with CHD for arrhythmias. In capableoflonger-durationcontinuousrecordings(typically2-
patients with symptoms, the primary task involves deter- 4 weeks) have become available, combining the best features
mining whether the complaint is rhythm-related and, if so, ofeventrecorderswiththebestattributesofHoltermonitors.
documenting or replicating the rhythm disturbance so that Event recorders come in 2 basic forms: noninvasive and
appropriate treatment can be instituted. In asymptomatic implantable. The former are most commonly used. Although
patients, the task is to detect or predict arrhythmias and data are limited, in select cases where the index of suspicion
institute therapy in advance of serious symptoms through a for a malignant arrhythmia is high but noninvasive moni-
processofsurveillancetestingandriskassessment,whichisin toringinnotfeasible orhasbeen unrevealing,animplantable
many ways a far more challenging and imperfect exercise.6 loop recorder may prove valuable.75,81
PK
Ah
Ca
ESiry
Table5.1. TypicalECGfeaturesinadultswithcommonformsofCHD /Het
Ra
Ventricular Sl.
Congenitaldiagnosis Rhythm PRinterval QRSaxis QRSconfiguration Atrialenlargement hypertrophy Particularities Ex
p
Secundumatrialseptal NSR;[IART/AFwith 1oAVB6%-19% 0o-180o;RAD;LADin rSr0 orrsR0 with RAE35% Uncommon “Crochetage”pattern ert
defect age Holt-OranorLAHB RBBBi>RBBBc Co
Ventricularseptal NSR;PVCs Normalormild[;1o RADwithBVH;LAD Normalorrsr0;possible PossibleRAE(cid:3)LAE BVH23%-61%;RVH Katz-Wachtel ns
defect AVB10% 3%-15% RBBB withEisenmenger phenomenon en
AVcanaldefect NSR;PVCs30% 1oAVB>50% ModtoextremeLAD; rSr0 orrsR0 PossibleLAE Uncommoninpartial; Inferoposteriorly su
s
Normalwith BVHincomplete; displacedAVN S
atypical RVHwith ta
Eisenmenger te
m
Patentductus NSR;[IART/AFwith [PR10%-20% Normal DeepSV1,tallRV5 LAEwithmoderate Uncommon Ofteneitherclinically en
arteriosus age andV PDA silentor t
6 o
Eisenmenger n
Pulmonarystenosis NSR Normal Nowrmithalmifomdeirldat;eR/AD Normal;severity PossibleRAE RVcHor;resleavteersitwyithR:S AxcisordreevlaiatetisownithRVP Arrhy
severe inV andV th
1 6 m
Aorticcoarctation NSR Normal NormalorLAD Normal PossibleLAE LVH,especiallyby PersistentRVHrare ia
voltagecriteria beyondinfancy s
Ebsteinanomaly NSR;possibleEAR, 1oAVBcommon; NormalorLAD Low-amplitude RAEwithHimalayanP DiminutiveRV Accessorypathway in
A
SVT;AF/IART shortifWPW multiphasicatypical waves common;QII,III, d
u
40% RBBB aVFandV1-V4 lt
Surgicallyrepaired NSR;PVCs;IART Normalormild[ NormalorRAD;LAD RBBB90% PeakedPwaves;RAE RVHpossibleif QRSduration(cid:3)QTd Co
TOF 10%;VT12% 5%-10% possible RVOTobstruction predictiveofVT/ ng
orPHT SCD en
L-TGA NSR 1oAVB>50%;AVB LAD Absenceseptalq;Qin Notifnoassociated Notifnoassociated AnteriorAVN;Positive ita
l
2%/year III,avFandright defects defects Tprecordial;WPW H
precordium withEbstein ea
D-TbaGfflAe/intra-atrial SinEuAsRb;rajduync6ti0o%na;l; Normal RAD AbdseenepceSoifnql,esftmallr, PossibleRAE RVH;diminutiveLV PoossribTleVAsVurBgeirfyVSD rtDis
IART25% precordium ea
UVHwithFontan Sinusbrady15%; NormalinTA;1oAVB LADinsingleRV,TA, Variable;[[RandS RAEinTA RVHwithsingleRV; Absentsinusnodein se
EAR;junctional; inDILV singleLVwith amplitudesinlimb possibleLVHwith LAI;AVblockwith
IART>50% noninvertedoutlet andprecordialleads singleLV L-looporAVCD
Dextrocardia NSR;P-waveaxis Normal RAD Inversedepolarization Notwithsitusinversus LVH:tallRV-V; Situssolitus:normalP
1 2
105o-165owithsitus andrepolarization RVH:deepQ,small waveaxisandsevere
inversus RV andtallRright CHD
1
lateral
ALCAPA NSR Normal PossibleLAD Pathologicant-latQ PossibleLAE Selectivehypertrophy Possibleischemia
waves;possibleant- ofposterobasalLV
septQwaves
AF¼atrialfibrillation;ALCAPA¼anomalousleftcoronaryarteryfromthepulmonaryartery;AVB¼atrioventricularblock;AVCD¼atrioventricularcanaldefect;AVN¼AVnode;BVH¼biventricular
hypertrophy;CHD¼congenitalheartdisease;DILV¼double-inletleftventricle;EAR¼ectopticatrialrhythm;IART¼intra-atrialreentranttachycardia;LAD¼left-axisdeviation;LAE¼leftatrialenlargement;
LAHB¼leftanteriorhemiblock;LAI¼leftatrialisomerism;LV¼leftventricle;LVH¼leftventricularhypertrophy;NSR¼normalsinusrhythm;PDA¼patentductusarteriosus;PHT¼pulmonaryhypertension;
RAD¼right-axisdeviation;RAE¼rightatrialenlargement;PVC¼prematureventricularcontraction;RBBB¼rightbundlebranchblock(c¼complete;i¼incomplete);RV¼rightventricle;RVH¼right
ventricularhypertrophy;RVOT¼rightventricularoutflowtract;RVP¼rightventricularpressure;SCD¼suddencardiacdeath;SVT¼supraventriculartachycardia;TA¼tricuspidatresia;TOF¼tetralogyofFallot;
TV¼tricuspidvalve;VSD¼ventricularseptaldefect;VT¼ventriculartachycardia;WPW¼Wolff-Parkinson-Whitesyndrome.
ReproducedwithpermissionfromKhairyP,MarelliAJ.Clinicaluseofelectrocardiographyinadultswithcongenitalheartdisease.Circulation2007;116:2734-2746.77
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5.3.1.3. Cardiopulmonary exercise testing. Exercise testing has the 5.3.2.2. Cardiac MRI. CardiacMRIhasbecomeanincreasingly
advantage of providing data regarding rhythm in combination important tool in evaluation of CHD patients with arrhyth-
withfunctionalstatusandmaybeusefulforevaluationofpatients mias.87 It provides data to supplement echocardiographic
with exertional symptoms. Although exercise testing does assessment of anatomy, valve performance, and ventricular
not typically result in reliable replication of sustained clinical function.Inaddition,imagescanbeimportedintoarrhythmia
tachyarrhythmias, it can provide information regarding mappingsystemstoprovide3-dimensionalrepresentationsofthe
sinus node behavior, AV conduction, and nonsustained tachy- endocardial surface that can be adapted for substrate mapping
arrhythmiasthatmayreflecttheunderlyingcauseofsymptoms.82 andactivationmappingofbothatrialandventriculartachycar-
dias.57,88Incircumstanceswhereimporting3-dimensionalim-
5.3.1.4. Data from cardiac rhythm management devices. Modern
age data to facilitate arrhythmia mapping is desired but MRI
pacemakersandimplantablecardioverter-defibrillators(ICDs)
cannot be performed because of implanted cardiac rhythm
have the ability to function like event recorders. Program-
management devices, CT imaging can be substituted for this
mable parameters can allow the automatic recording of atrial,
purpose,althoughradiationexposureprobablymandatesthatit
ventricular, or summed electrograms that meet specified
only be performed when it will directly impact management.
criteria. In many devices, patients can actuate a recording
GiventheexpandingclinicalindicationsforMRIinadultswith
using a programmable magnet response. Because of the long-
CHD, when indicated, MRI conditional implantable cardiac
term nature of these recordings, these devices can provide
arrhythmiadevicesshouldbeconsidered.
excellent information on arrhythmia burden. In a recent
single-center retrospective series, 71% of patients underwent 5.3.2.3. Cardiac catheterization/angiography. Cardiac catheteriza-
treatment modification as a result of device telemetry.83 tion allows direct pressure measurements under controlled
conditions. This may be particularly important in situations
5.3.1.5.Electrophysiologicstudy. Providingtheclinicalarrhythmia
where small gradients can have an important clinical impact
ispresentor canbeinduced duringtheprocedure,diagnostic (e.g.,Fontan,Mustardbaffles).Coronaryangiographyshould
electrophysiologic studies offer the most definitive means of
be considered in patients undergoing evaluation for ventric-
characterizingtheessentialcomponents(location,mechanism,
ular arrhythmias who are over 40 years of age or those with
and other attributes) of the rhythm disturbance. The use of
additional cardiovascular risk factors such as congenital
this test as a screening tool to assess risk of sudden cardiac
anomalies of the coronary arteries, coronary arteriovenous
death and ventricular arrhythmias is discussed in the evalua- fistulae, a history of coronary surgery, or the potential for
tion of the asymptomatic patient. coronary compression by vascular conduits or stents.89
5.3.2. Hemodynamic testing for symptomatic patients
HemodynamictestinginthesymptomaticadultwithCHD 5.3.3. Recommendations for the evaluation and diagnosis of
may alter the pretest probability of finding a heart rhythm arrhythmias in symptomatic adults with CHD
abnormality at the root of the patient’s symptoms and deter- Recommendations
minethepotentialclinicalimpactofsucharhythmproblem.84 a.Noninvasiveevaluation
The firstobjective istoclearly defineanatomy.Themodified ClassI 1. Athoroughclinicalhistoryandphysicalexaminationshouldbe
natural history of a given CHD lesion often depends exten- conductedinadultswithCHDandsymptomssuggestiveof
sively on the type of palliative or corrective interventions.85 arrhythmias(e.g.,palpitations,presyncope,syncope),docu-
mentednew-onsetorworseningarrhythmias,orresuscitated
Review of operative reports in conjunction with some form suddencardiacdeath(Levelofevidence:C).90
of imaging study, if not recently performed, is generally indi- 2. Aresting12-leadECGisindicatedinadultswithCHDwhoare
cated. The focus of the evaluation then shifts to the patient’s evaluatedforarrhythmias(Levelofevidence:C).77
hemodynamic and functional status. Identification of 3. AmbulatoryECGmonitoringisindicatedwhenthereisaneed
toclarifyorexcludeanarrhythmiadiagnosis,correlatearrhyth-
arrhythmogenicsubstrates,suchasventriculardysfunction,an
miaswithsymptoms,evaluaterisk,ordetermineappropriate
enlarged or hypertrophied cardiac chamber related to valve therapy(Levelofevidence:B).78-80,91
dysfunction, or other hemodynamic derangement, may pro- 4. Cardiaceventlooprecordersareindicatedtoestablishwhetheror
videimportantdiagnostic and prognostic clues. notsporadicsymptomsarecausedbytransientarrhythmias
(Levelofevidence:C).75,81
5. Patients with suspected arrhythmias and implanted cardiac
5.3.2.1. Echocardiography. Widely available and noninvasive, rhythmmanagementdevicesshouldundergodeviceinterroga-
transthoracic echocardiography is generally the initial imaging tiontoretrievediagnosticinformationprovidedbyarrhythmia
methodofchoice.8Althoughusuallyquitesensitiveandaccurate detectionalgorithms,trendeddata,histograms,and/orintracar-
inassessingsemilunarandAVvalvedysfunction,aswellasleft diacelectrogramrecordings(Levelofevidence:B).83,91,92
6. Implantablelooprecordersareusefulincaseswheretheindexof
ventricularsizeandfunction,theaccuracyofechocardiography
suspicionforamalignantarrhythmiaishigh(e.g.,syncope)buta
forquantitativeassessmentofrightventricularsizeandfunction symptom–rhythmcorrelationcannotbeestablishedbyconven-
hasbeenquestioned.86Echocardiographymayalsofallshortin tionalnoninvasivetechniquesorinvasiveelectrophysiologic
evaluationofsystemicvenousbaffleswheresmallhemodynamic testing(Levelofevidence:B).81,93
gradientsmaybedifficulttoassessbutnonethelesshaveimpor- Class CardiopulmonaryexercisetestingcanbeusefulinadultswithCHD
IIa andknownorsuspectedexercise-inducedarrhythmiasinorderto
tantclinicalimplications.Intheseandothersettings,additional
provokethearrhythmia,establishadiagnosis,orassessresponseto
testingmaybeindicated.Transesophagealechocardiographycan therapy(Levelofevidence:C).94,95
behelpfuliftransthoracicechocardiographicwindowsareinad- Class Cardiopulmonaryexercisetestingmaybeusefulinselectedadults
equate,ifaprostheticvalveormaterialispresent,andtobetter IIb withCHDandarrhythmiasaspartofabroaderworkupto
assessbafflefunctionorcomplexCHDanatomy.8 edxecslautudreattiroigngeorrinmgyfoaccatordrsiasluicschhaesmeixae(rLciesvee-linodfuecveiddenocxey:gCen).94