Andersons pediatric cardiology 868
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Introduction
Themostcommoncongenitalmalformationsafflictingthetricuspidvalveare
Ebsteinmalformationandtricuspidvalvardysplasia.Theselesionsare
consideredinthischapter,togetherwithabrieflookatacquiredmalformations.
Tricuspidvalvarabnormalities,orabnormalitiesofthemorphologicallyright
atrioventricularvalve,arealsooftenassociatedwithatrioventricularseptal
defectswithcommonatrioventricularjunction(seeChapter31),ventricular
septaldefectwithstraddlingvalve(seeChapter32),atrioventriculardiscordance
(seeChapter38),orpulmonaryatresiawithintactseptum(seeChapter43).
Theselesionsaredescribedindetailinotherchaptersofthisbook.However,
Uhlanomalyandfattyreplacementofthewalloftherightventricle,thelatter
nowdescribedasarrhythmogenicrightventricularcardiomyopathy,areso
frequentlydiscussedinthesettingofEbsteinmalformationthatbrief
considerationisgiventothesetwoentitieseventhoughtheyarenot
malformationsofthetricuspidvalve.
EbsteinMalformation
Ebsteinmalformationhasavariablenaturalhistorydependingonthedegreeof
abnormalityofthetricuspidvalvarapparatusandrightventricle,bothofwhich
mayrangefrommildtosevere.Ifthedeformityofthetricuspidvalveissevere
andtheventriclesignificantlydysfunctional,profoundcongestiveheartfailure
mayoccurintheneonatalperiodorevenresultinintrauterinedeath.Attheother
endofthespectrum,patientswithamilddegreeofdisplacementoftheseptal
hingeawayfromtheatrioventricularjunctionmayneverdevelopsymptomsor
mayremainasymptomaticuntillateadultlife.
Ebstein'sowndescriptionofthemalformation,withillustrationsbyDr.Weiss
(Fig.33.1)wasbasedontheanatomicfindingsrelatingtotheheartofJoseph
Prescher,a19-year-oldlaborerwithcyanosis.Prescherhadbeentroubledwith
dyspneaandpalpitationssincechildhood.ThefirstcasedescribedintheEnglish
literaturewaspublishedin1900,1butitwasnotuntil1951thatthediagnosiswas
madeduringlife,usingangiocardiography.2Bythe1950s,successfulsurgical
palliationhadbeenachieved,andtheassociationwithWolff-Parkinson-White
syndromehadbeenrecognized.The1960sheraldedthefirstattemptsat
correctivesurgery,includingvalvarreplacement3andrepair.4Throughoutthe
1960sand1970s,thediseasewasthoughttobeextremelyrare,accountingfor
nomorethan0.3%ofcongenitalheartdisease,5,6givinganestimatedincidence
atthattimeofapproximately24per1millionlivebirths.
FIG.33.1 IllustrationoftheheartofJosephPrescherasseenfromthe
anterioraspect,andofthefunctionalrightventricle,asillustratedfor
WilhelmEbsteinbyDrWeiss.Notehowtheleafletsofthedeformedvalve
closeinbifoliatefashion,formingakeyholeorificethatopenstowardthe
outletcomponentoftherightventricle.
Echocardiographyprovidesaconvenientandreadilyavailablemethodfor
diagnosis,eveninfetallife.7Themalformationiscurrentlyknowntobemore
commonandtohaveabroaderspectrumthanpreviouslyappreciated.Infact,a
seriesofmorethan200casescollectedfromhospitalsinsoutheastEngland
revealedanearlyfivefoldincreaseinthenumberofdiagnosedcasesperdecade,
withmorethanhalfofthepatientsyoungerthan1yearatdiagnosis.8Bythe
1990sitwasestimatedthattheincidenceofEbsteinmalformation,including
asymptomaticcases,wasapproximately1in200,000livebirths.9
Anatomy
TheessenceofEbsteinmalformationisadherenceofvariablesegmentsof
