Andersons pediatric cardiology 62
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wasconnectedtoamorphologicallyrightventricle,aswellastheheartinwhich
theleft-sidedatriumwasconnectedtoamorphologicallyleftventricle.The
arrangementsaredifferentiatedsimplybydescribingalsotheventricular
topology.
Boththepositionandtherelationshipsofincompleteventriclesneedtobe
describedinheartswithuniventricularatrioventricularconnections.Herethe
relationshipsareindependentofboththeconnectionsandtheventricular
morphology.Theincompleterightventricleisusuallyanteriorandrightsidedin
classicaltricuspidatresia,butitcanbeanteriorandleftsidedwithoutinanyway
alteringtheclinicalpresentationandhemodynamicfindings.Similarly,inhearts
withadouble-inletventricle,thepositionoftheincompleteventricleplaysonly
aminorroleindeterminingtheclinicalpresentation.Althoughacasecanbe
madeforinterpretingsuchheartswithuniventricularatrioventricular
connectionsonthebasisofpresumedmorphogenesisinthesettingofright-or
left-handedtopologies,therearesufficientexceptionstomakethisapproach
unsuitableintheclinicalsetting.Thereforewhenwedescribethepositionof
incompleteventricles,wesimplyaccountfortheirlocationrelativetothe
dominantventricle,takingnoteagainwhennecessaryofright-left,anteriorposterior,andsuperior-inferiorcoordinates.Onoccasion,itmayalsobe
advantageoustodescribeseparatelythepositionofapicalandoutletcomponents
ofanincompleteventricle.
VentriculoarterialJunctions
Mostpolemicsconcerningtheventriculoarterialjunctionsdevolveduponthe
failuretodistinguishbetweenthewaythearterialtrunksarosefromthe
ventricularmassasopposedtotheirrelationstoeachother,alongwithundue
emphasisonthenatureoftheinfundibulumssupportingtheirarterialvalves.
Whenthesefeaturesaredescribedindependently,followingthepreceptsofthe
morphologicmethod,allpotentialfordisagreementisremoved.
OriginoftheArterialTrunksFromthe
VentricularMass
Aswithanalysisoftheatrioventricularjunctions,itisnecessarytoaccount
separatelyforthewaythearteriestakeoriginandthenatureofthevalves
guardingtheventriculoarterialjunctions.Therearefourpossibletypesoforigin.
Concordantventriculoarterialconnectionsexistwhentheaortaarisesfroma
morphologicallyleftventricle,andthepulmonarytrunkfromamorphologically
rightventricle,betheventriclescompleteorincomplete.Thearrangementwhere
theaortaarisesfromamorphologicallyrightventricleoritsrudiment,andthe
pulmonarytrunkfromamorphologicallyleftventricleoritsrudiment,produces
discordantventriculoarterialconnections.Double-outletconnectionisfound
whenbotharteriesareconnectedtothesameventricle,whichmaybeofright
ventricular,leftventricular,orindeterminateventricularpattern.Aswith
atrioventricularvalves,overridingarterialvalves(seelater)areassignedtothe
ventriclesupportingthegreaterpartsoftheircircumference.Thefourth
ventriculoarterialconnectionissingleoutletfromtheheart.Thismaytakeoneof
fourforms.Acommontrunkexistswhenbothventriclesareconnectedviaa
commonarterialvalvetoonetrunkthatgivesrisedirectlytothecoronary
arteries,atleastonepulmonaryartery,andthemajorityofthesystemic
circulation.Asolitaryarterialtrunkexistswhenitisnotpossibletoidentifyany
remnantofanatreticpulmonarytrunkwithinthepericardialcavity.Theother
formsofsingleoutletaresinglepulmonarytrunkwithaorticatresiaorsingle
aortictrunkwithpulmonaryatresia.Theselattertwocategoriesdescribeonly
thosearrangementsinwhich,usingclinicaltechniques,itisnotpossibleto
establishthepreciseconnectionoftheatreticarterialtrunktoaventricular
cavity.Ifitsventricularorigincanbeestablishedbutisfoundtobeimperforate,
thentheconnectionisdescribed,alongwiththepresenceofanimperforatevalve
(seelater).Itisalsonecessaryinheartswithsingleoutlettodescribethe
ventricularoriginofthearterialtrunk.Thismaybeexclusivelyfromarightora
leftventricle,butmoreusuallythetrunkoverridestheseptum,takingitsorigin
frombothventricles.
Therearefewermorphologiesforthevalvesattheventriculoarterialthanat
theatrioventricularjunctions.Acommonarterialvalvecanexistonlywitha
specifictypeofsingleoutlet,namelycommonarterialtrunk.Straddlingofan
arterialvalveisimpossiblebecauseithasnotensionapparatus.Thusthe
possiblepatternsaretwoperforatevalves,oneorbothofwhichmayoverride,or
oneperforateandoneimperforatevalve.Aswithoverridingatrioventricular
valves,thedegreeofoverrideofanarterialvalvedeterminesthepreciseorigin
ofthearterialtrunkfromtheventricularmass,theoverridingvalve,orvalves,
beingassignedtotheventriclesupportingthegreaterpartofitscircumference.
Forexample,ifmorethanhalfofanoverridingpulmonaryvalvewasconnected
toarightventricle,theaortabeingconnectedtoaleftventricle,wewouldcode
concordantconnections.Ifmorethanhalftheoverridingaorticvalvewas
connectedtotherightventricleinthissituation,wewouldcodedouble-outlet
connections.Inthisway,weavoidthenecessityforintermediatecategories.
Nonetheless,theprecisedegreeofoverrideisbeststatedwheneveranoverriding
valveisfound.Thisisdonetothebestofone'sability,usingwhichever
techniquesareavailable,andrecognizingthesubjectivenatureofthetask.Inthis
setting,aswithatrioventricularconnections,weerronthesideofthemore
usuallyencounteredpattern.
ArterialRelationships
Relationshipsareusuallydescribedatvalvarlevel,andmanysystemsfor
nomenclaturehavebeenconstructedonthisbasis.Itremainsafactthat“dtransposition”isusedasthoughsynonymouswithallcombinationsof
concordantatrioventricularanddiscordantventriculoarterialconnections,
althoughthiswasnothowthetermwasinitiallyused.Inthesameway,“ltransposition”wasusedasasynonymforcongenitallycorrectedtransposition.
Inreality,wenowknowthattherelationshipsofthearterialvalvesareapoor
guidetoventriculartopology.Describingarterialvalvarpositionintermsof
leftnessandrightnessalsotakesnocognizanceofanteroposteriorrelationships,
