Andersons pediatric cardiology 810
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tractduetoatissuetag(arrow).(B)Apicallong-axisviewfromapatient
withseparateleftandrightatrioventricularvalveorificesandaverydeep
scoopofthemuscularinterventricularseptum.Thereisseverenarrowing
oftheelongatedleftventricularoutflowtractcombinedwithabnormal
connectionsofvalvartissue(asterisk).Ao,Aorta;la,leftatrium;lv,left
ventricle;rv,rightventricle.
Isomerismoftheatrialappendagesisfrequentlyfound(seeChapter26).The
morphologicrightventriclemaybetotherightortotheleftofthemorphologic
leftventricle,givingeitherright-orleft-sidedventriculartopology.Theleft-side
patternmaygivetheimpressionofdiscordantatrioventricularconnections(see
Chapter38).Whenthereisisomerismoftheatrialappendagescoexistingwith
anatrioventricularseptaldefect,identificationoftherightventricledependson
therecognitionofcordsfromthebridgingleafletsinsertingintotheseptum
alongwiththecoarseapicaltrabeculations.Incontrast,nocordsinsertintothe
leftventricularsurfaceoftheseptum,andthemorphologicleftventriclehas
pairedpapillarymuscles.
DopplerInterrogation
Whenanypatientwithanatrioventricularseptaldefectisbeinginvestigated,
color-flowDopplerinterrogationisusedtodemonstrateinteratrial,
interventricular,orventriculoatrialshunting.Pulsedandcontinuous-wave
Dopplerinterrogationcanbeusedtomeasurethedropinpressureacrossany
interventricularcommunication,acrosstheleftorrightventricularoutflowtract,
andacrossthecommonatrioventricularvalveoreithersideinitsdividedstate.A
measurementacrosstherightatrioventricularvalvepermitsanaccurate
estimationoftherightventricularandpulmonaryarterialsystolicpressuresin
theabsenceofrightventricularoutflowobstruction.Itisimportanttobeaware,
however,thatthevelocityprofileintherightatriumwillnotallowanaccurate
predictionofrightventricularsystolicpressureifthereisshuntingfromtheleft
ventricletotherightatrium.Inaddition,Dopplerinterrogationallows
assessmentofthelocationandseverityofanyvalvarregurgitationorstenosis
(Figs.31.34and31.35;Videos31.14and31.15),withthelimitationsof
assessingatrioventricularvalvarstenosisinthisdefectbyDopplerinterrogation
alone,aspreviouslydiscussed.
FIG.31.34 ColorDopplerimagedemonstratingsevereleftatrioventricular
valveregurgitationfollowingcompleterepair.la,Leftatrium;lv,left
ventricle;ra,rightatrium.
FIG.31.35 ColorDopplerimagedemonstratingleftatrioventricularvalve
stenosiswithdiastolicaliasingofflowstartingatthelevelofthevalve
(arrow).la,Leftatrium;lv,leftventricle.
Three-DimensionalEchocardiography
Withtherapiddevelopmentofthree-dimensionalechocardiography,
atrioventricularseptaldefectisamongthefirstcongenitallesionsinwhichits
valuewasdemonstrated.60,61Thecomplexthree-dimensionalspecial
arrangementofthecommonatrioventricularvalveandvalvarapparatusin
relationtotheatrialandventricularcomponentsoftheatrioventricularseptal
defectarebetterappreciatedinthisthree-dimensionalrendition,whichis
especiallyusefulforsurgicalplanning(Figs.31.36and31.37;Videos31.16to
31.18).Morespecifically,variousabnormalitiesoftheatrioventricularvalve,
suchasadouble-orificeleftatrioventricularvalve(seeFig.31.25),maybebetter
demonstratedwiththismodality.Withimprovedtechnology,three-dimensional
echocardiographyisincreasinglyusedinchildrenowingtothegoodacoustic
windowsandadequateframerates.55
FIG.31.36 Three-dimensionaltransthoracicechocardiographicimage
fromtheatrialperspectivedemonstratingtwoseparateatrioventricular
valves,bothwithatongueofbridgingtissue(arrowheads)connectingthe
superiorbridgingleaflet(SBL)totheinferiorbridgingleaflet(IBL)onthe
crestofthemuscularinterventricularseptum.Theleftatrioventricularvalve
isseentobetrifoliateinconfiguration,withtheso-calledcleftformedbythe
functionalzoneofappositionbetweentheSBLandIBL.Ao,Aorta;LA,left
atrium;RA,rightatrium;RVOT,rightventricularoutflowtract.(Courtesy
JohnSimpson,EvelinaLondonChildren’sHospital,UnitedKingdom.)
