Andersons pediatric cardiology 52
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theatrialandventricularcomponents.Atthistime,theyplacedlessemphasisfor
descriptiononthefashioninwhichtheatrialandventricularchamberswere
joinedtogetheracrosstheatrioventricularjunctions.Asimilarapproach,
concentratingonarterialrelationships,hadbeentakenbydelaCruzetal.7when
theyformulatedtheirconceptofarterioventricularconcordanceanddiscordance.
Theseapproacheswereunderstandablebecauseitwasoftendifficult,atthat
time,todeterminepreciselyhowtheadjacentstructureswerelinkedtogether.
FIG.1.1 Theessenceofsequentialsegmentalanalysisdependson
recognitionofthetopologicarrangementofthethreecardiacsegmentsand
combinesthiswithanalysisofthefashionsinwhichthesegmentsare
joined,orarenotjoined,toeachother.
Allwaschangedbytheadventofcross-sectionalechocardiography.Sincethe
mid-1970s,ithasbeenpossiblewithprecisiontodeterminehowatriumsare,or
arenot,joinedtoventricles,andsimilarlytoestablishtheprecisemorphology
foundattheventriculoarterialjunctions.Ourpreferredsystemevolved
concomitantlywiththedevelopmentofechocardiographyandconcentrateson
thevariationspossibleacrosstheatrioventricularandventriculoarterial
junctions.Wecallthissystemsequentialsegmentalanalysis(seeFig.1.1).In
makingsuchanalysis,wedonotignorethesegmentsthemselves.Indeed,
junctionalconnectionscannotbeestablishedwithoutknowledgeofsegmental
topology.
Oursystem,throughoutitsevolution,8–12hasfollowedthesamebasicand
simplerules.Fromtheoutset,wehaveformulatedourcategoriesonthebasisof
recognizableanatomicfacts,avoidinganyspeculativeembryologicassumptions.
Again,fromthestart,wehaveemphasizedthefeaturesofthemorphologyofthe
cardiaccomponents,thewaytheyarejoinedornotjoinedtogether,andthe
relationsbetweenthem,asthreedifferentfacetsofthecardiacmake-up.The
clarityofthesystemdependsuponitsdesign.Somearguethatbrevityisan
importantfeatureandhaveconstructedformidablecodificationstoachievethis
aim.13However,inthefinalanalysis,clarityismoreimportantthanbrevity.
Thereforewedonotshyfromusingwordstoreplacesymbols,evenifthis
requiresseveralwords.Whereverpossible,westrivetousewordsthatareas
meaningfulintheirsystematicroleasintheireverydayusage.Inourdesireto
achieveoptimalclarity,wehavemadechangesinourdescriptionsoverthe
years,mostnotablyinouruseoftheterm“univentricularheart.”14,15Wemake
noapologiesforthesechangesbecausetheirformulation,inresponsetovalid
criticisms,haseradicatedinitiallyillogicalpointsfromoursystemtoits
advantage.Itisourbeliefthatthesystemnowadvocatedisentirelylogical,and
wehopeitissimple.
BasicConceptsofSequentialSegmental
Analysis
Thesystemweadvocatedependsfirstupontheestablishmentofthearrangement
oftheatrialchambers.Thereafter,attentionisconcentratedontheanatomic
natureofthejunctionsbetweentheatrialmyocardiumandtheventricular
myocardialmass.Thisfeature,whichwedescribeasatypeofconnection,is
separatefromtheadditionalfeatureofthemorphologyofthevalveorvalves
thatguardthejunctions.Therearetwojunctionsinthenormallyconstructed
heart,andusuallytheyareguardedbytwoseparatevalves.Thetwo
atrioventricularjunctionscanbeguarded,onoccasion,byacommonvalve.If
wearetoachievethisanalysisoftheatrioventricularjunctions,wemustalso
determinethestructure,topology,andrelationshipsofthechamberswithinthe
ventricularmass.Havingdealtwiththeatrioventricularjunctions,the
ventriculoarterialjunctionsarealsoanalyzedintermsofthewaythearterial
trunksarejoinedtotheventricularmassandthemorphologyofthearterial
valvesguardingtheirjunctions.Separateattentionisdirectedtothemorphology
oftheoutflowtractsandtotherelationshipsofthearterialtrunks.Acatalogis
madeofallassociatedcardiacand,wherepertinent,noncardiac,malformations.
Includedinthisfinalcategoryaresuchfeaturesasthelocationoftheheart,the
orientationofitsapex,andthearrangementoftheotherthoracicandabdominal
organs.
Implicitinthesystemistheabilitytodistinguishthemorphologyofthe
individualatriumsandventriclesandtorecognizethetypesofarterialtrunk
takingoriginfromtheventricles.Thisisnotasstraightforwardasitmayseem;
often,incongenitallymalformedhearts,thesechambersorarterialtrunksmay
lacksomeofthemorphologicfeaturesthatmostobviouslycharacterizethemin
thenormalheart.Themostobviousfeatureofthemorphologicallyleftatriumin
thenormalheartistheconnectiontoitofthepulmonaryveins.Inheartswith
totallyanomalouspulmonaryvenousconnection,theseveinsconnectin
extracardiacfashion.Inspiteofthis,itisstillpossibletoidentifytheleftatrium.
Itisconsiderationsofthistypethatpromptedtheconceptweuseforrecognition
ofthecardiacchambersandgreatarteries.DubbedbyVanPraaghandhis
colleaguesthe“morphologicmethod”16andbasedontheinitialworkofLev,17
theprinciplestatesthatstructuresshouldberecognizedintermsoftheirown
