Andersons pediatric cardiology 1356
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ClinicalFeatures
Clinicalmanifestationsaresimilartothoseseeninpatientswithaortic
regurgitation.Neonatesandinfantspresentwithfeaturesofcongestiveheart
failure(e.g.,tachypnea,poorfeedingandpoorgrowth).Inseverecases,infants
maypresentinshockwithpoorsystemicorganperfusion(e.g.,decreased
coronaryarteryperfusion)duetodiastolicrunoff.Fetaldemiseorsuddendeath
inaninfantcanoccuriftherunoffissevere.Rarelyinthecaseofasmallaorto–
leftventriculartunnel,theremaybenosymptomspresent.Physicalfindings
includeahyperdynamicprecordiumandboundingarterialpulses.Ato-and-fro
murmurisheardwithalouddiastoliccomponent.Hepatomegalyandpoordistal
limbperfusionmaybeevidentinextremecases.Althoughnowadayscommonly
seenfirstininfancy,anaorto–leftventriculartunnelmaypresentinchildhood
andadulthoodasamurmuronly.Ararecaseofpresentationinadulthoodafter
evaluationforacerebrovascularaccidentduethrombusformationinthetunnel
andsystemicembolizationhasbeenreported.54Duetoadvancesinimaging
techniques,fetaldiagnosisofthelesion(discussedlater)canalsobemade.
Investigations
Insymptomaticpatients,cardiomegalyisseenonchestradiographsandthe
electrocardiogramisconsistentwithsignsofleftventricularvolumeloadand
increasedleftventricularforcesasaresultofleftventricularhypertrophy.
Ischemicchangescanbeseenintheelectrocardiogramduetodiastolicrunoffin
severecases.Transthoracicechocardiography(Fig.51.16)definestheanatomy,
andmeticulousimagingmustbeperformedtodistinguishthelesionfrom
isolatedaorticregurgitation,coronaryarteryfistulae,andrupturedsinusof
Valsalvaaneurysms.Delineationofthecoronaryarteriesmustalsobe
performed.Secondaryeffectsofregurgitationfromtheaorto–leftventricular
tunnel(e.g.,dimensionsandfunctionoftheleftventricle[diastolicandsystolic
dimensions]andleftventricularfunction)areofparamountimportanceand
provideindicationsfortreatmentandtimingforeventualcorrection.Following
surgical/catheter-basedtreatmentofthetunnel,functionoftheaorticvalve(with
particularemphasisonregurgitationandmechanismofregurgitation)shouldbe
evaluatedalongwithassessmentforresidualflowthroughthetunnel.47Forolder
childrenandadults,transesophagealechocardiographymayberequiredto
delineatetheanatomicdetailsoftheaorto–leftventriculartunneland
surroundingstructures.55CardiacMRIandCTscans(Fig.51.17)canaidin
anatomicdetailsofthelesion.Angiographyviacardiaccatheterizationisrarely
neededforthediagnosisandisgenerallyreservedifthereisaneedtodefinethe
coronaryarteryanatomyorifthereisanintentiontooccludethetunnelinthe
cardiaccatheterizationlaboratorywithadevice.Fetaldiagnosiscanbemadeand
maybehelpfulforplanningtimelyinterventionsincriticallyillneonatesandin
improvingpostnataloutcomes.50,56
FIG.51.16 Transthoracictwo-dimensionalechocardiographicimagingin
theparasternallongaxisofanaorto–leftventriculartunnelinaneonate
withsymptomsofheartfailure.(A)Notethetunnelbypassingtheaortic
valve(whitearrowrepresentstheaorticend;yellowarrowrepresentsthe
leftventricularend).(B)CorrespondingcolorDopplerimaginginthesame
echocardiographicviewdemonstratesregurgitationthroughthetunnelto
theleftventricle.
FIG.51.17 Computedtomographyscanshowinganaorto–leftventricular
tunnelinthesameneonateshowninFig.51.16.Thetoparrowpointsto
theaorticorigin,andthebottomarrowpointstoinsertionintotheleft
ventricle.
