Andersons pediatric cardiology 1306
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CongenitalDeficiencyofthePericardium
Anintegralpartofthevariousformsofextrathoracicheartisagrossdeficiency
ofthefibrouspericardialsac.Suchdeficienciescanalsobefoundwhentheheart
isinitsanticipatedintrathoracicposition,althoughthelesionisexceedingly
rare.3Wehaveknowinglyobservedonlyasinglecaseatpostmortem,achance
findingina68-year-oldpatient.15Thereforecasescanbeentirelyasymptomatic.
Alternatively,suchpatientsmayhavechestpainthatcanresembleangina.When
associatedwithotheranomalies,suchasdiaphragmaticherniaorlesionsofthe
heart,itistheassociatedmalformationsthatdominatetheclinicalpicture.The
biggestintrinsicproblemsoccurwithrelativelylocalizedleft-sideddeficiencies
ofthepericardium.Eithertheventriclesortheleftatrialappendagecanbecome
herniatedthroughasmallopening,withstrangulationand,inextremecases,
death.Limiteddeficiencyofthefibroussacontherightsidecanresultin
herniationofthelungintothepericardialcavity,withsubsequentobstructionof
thesuperiorcavalvein.Thediagnosisisoftenmade,oratleastsuggested,from
thechestradiograph(Fig.49.5).Completeabsenceoftheleftpericardiumis
characterizedbyleftwarddisplacementoftheheartintheabsenceofpectus
excavatum(Fig.49.6).Inthissetting,thereisincreasedmobilityandincreased
changeinvolumeofallthecardiacchambersinsystoleanddiastole.Although
themarginofthedeficientpericardiumcannotbeidentified,thediagnosiscan
safelybemadewhenapartoftheleftlungisinterposedbetweenthepulmonary
trunkandaorticroot(seeFig.49.6D).16,17Whenthedefectissmallandthereis
herniationoftheleftappendage,theheartisnormallypositioned,butthe
malpositionedappendageproducesanexaggeratedbulgeintheregionofthe
pulmonaryknob(seeFig.49.5).Additionalimaging(Fig.49.7)canconfirm
suspectedherniationoftheappendage.Onlythesmalldefectsrequiresurgical
treatment,althoughlargedeficienciesmaynotbeentirelybenign.Thisis
becausethepericardialsacfunctionsasthecardiacseatbelt.Theheartismore
pronetotraumaticinjurywhenthepericardiumisdeficient.Surgicaltreatment
ofsmalldefectsisdoneeitherbyenlargingthedefect,incurringthesmallriskof
losingtheseat-belteffect,orbyclosureusingaflapofmediastinalpleura.
FIG.49.5 Chestradiographshowinganextensivebulgeintheleftborder
ofthecardiacsilhouette(arrows).Thisishighlysuggestiveofherniationof
theleftatrialappendagethroughapericardialdeficiency.Ao,Aorta;LA,left
atrium;LAA,leftatrialappendage;PA,pulmonaryartery;RA,rightatrium;
RAA,rightatrialappendage.
FIG.49.6 Posteroanterior(A)andlateral(B)chestradiographsindicative
ofcompleteabsenceofthepericardium.Asisconfirmedbythecomputed
tomographicimages(C–D),theheartextendstotheleftlateralwallofthe
chest.Thepresenceoflungtissue(asterisk)betweentheaortaandthe
pulmonarytrunkconfirmsthepericardialdeficiency.
