Andersons pediatric cardiology 1062

intheheartshownatleft,whereastheheartatrightshowsamousewith
pulmonarydominanceandinterruptionoftheaorticarch.


DiagnosticFeatures
AntenatalDiagnosis
Itmightbeexpectedthatcommonarterialtrunkwouldbedetectedduringthe
mid-trimesterscanforfetalanomalies,whichisroutineinmanycountries.In
practice,population-basedstudiesdemonstratethatthediagnosismayoftenbe
missed,19,20presumablybecausethefour-chamberviewoftheheartmayappear
tobenormalonsuperficialexamination.Nonetheless,moredetailed
examinationofthefetalheartshouldrevealaventricularseptaldefect.An
arterialtrunkthatoverridesthedefectistheonlyoutletthatarisesfromthe
ventricularmass.21Itshouldbepossibletodocumentthedegreeofregurgitation
orstenosisofthetruncalvalve,andthecourseandintegrityoftheaorticarch
(Table40.1).22Oneparticularchallengeintheantenatalexaminationoffetuses
inwhomonlyasinglearterialtrunkarisesfromthehearthasbeenin
distinguishingthosewithcommonarterialtrunkfromthosewithtetralogyof
Fallotwithpulmonaryatresia,althoughusingcurrenttechnologies,including
four-dimensionalspatiotemporalimagecorrelationechocardiography,this
distinctioncanbeachievedinmostcases.23
Table40.1
KeyDiagnosticFeaturesinCommonArterialTrunk
DiagnosticMethod
Fetalechocardiogram
Four-chamberview
Greatvessels
Aorticarch
Clinicalexamination
Inspection

Palpation
Auscultation

Electrocardiogram

Features
Ventricularseptaldefectwithtruncaloverride(mayappearnormal)
Singlearterialtrunk
Truncalregurgitation
Interruption
(?)Mildcyanosis
Failuretothrive
Tachypnea
Boundingpulses
Liverenlargement
Normalfirstheartsound
Mayhaveasinglesecondsound(althoughnotalways)
Ejectionclick
Ejectionsystolicmurmur
(?)Diastolicmurmuroftruncalregurgitation
Nonspecificusuallycombinedventricularhypertrophy


Chestradiograph

Echocardiogram
Parasternallongaxis

Parasternalshortaxis

Apicalfourchamber

Highparasternal

Cardiaccatheterization
Hemodynamics
Oximetry
Pulmonaryvasodilator
Angiocardiography

Cardiomegaly
Increasedpulmonaryvascularmarkings
Narrowarterialpedicle
Truncalorigin
Ventricularsizeandmuralthickness
Ventricularseptaldefect
Velocityofinterventricularshunting
Truncalregurgitation
Morphologyoftruncalvalve
Mechanismoftruncalregurgitation
Originofpulmonaryarteries
Stenosisofpulmonaryarteries
Originofcoronaryarteries
Ventricularoriginoftrunk
Truncalregurgitation
Truncalstenosis
Functionofatrioventricularvalves
Aorticarch
Arterialduct
Interruptionofaorticarch

Pressuremeasurementinrightandleftpulmonaryarteries
Pressuredropacrosstruncalvalve
Pulmonary-to-systemicbloodflowratio
Toassesspulmonaryvascularresponsiveness
Truncalinjectiontoexaminethedegreeofregurgitation
Selectivepulmonaryangiogram
Leftventriculogramtoevaluatethesizeandlocationofseptaldefects

Asignificantproportionoffetuseswillhaveassociatednoncardiac
anomalies,24withorwithoutadeletioninchromosome22.25

NeonatalPresentation
Thetypicalpatientwillpresentduringtheneonatalperiod,orinearlyinfancy,
withmildcentralcyanosis,ahyperactiveprecordium,andsignsofincreasing
congestivecardiacfailure.Therewillbedifficultiesinfeeding,failuretothrive,
tachypnea,andhepaticenlargement.Althoughaminordegreeofhypoxemiais
common,obviouscyanosisisafeatureofeitherraisedpulmonaryvascular
resistanceorpulmonarystenosis.Oncecardiacfailureisestablished,thechest
maybulgeinconsequenceofthecardiomegaly.
Atauscultation,thefirstheartsoundisusuallynormal,whereasthesecond
soundisaccentuated.Althoughitmightbeanticipatedthatthesecondsound
wouldalwaysbesingleinthepresenceofacommonarterialvalve,thereis
splittingofthesecondsoundinapproximatelyone-halfofinfants,documented
byphonocardiographyandbyauscultation.26Possibleexplanationsforthisare