Andersons pediatric cardiology 1576

sickle-shapeddeformityintheredcells.Thepathophysiologicconsequencesof
thisarevasoocclusivephenomenaandchronichemolysis.Organsaffectedby
thisprocessarethekidneys,lungs,liver,spleen,centralnervoussystem,and
bones.Thereareahostofpotentialcardiovascularsignsandsymptomsin
patientswithsicklecellanemia.Cardiacoutputisincreased,withanincreasein
strokevolume.Themostcommonsymptomsareexertionaldyspneaand
palpitations.Physicalexaminationrevealssignsofahyperdynamiccirculation.
Peripheralpulsesarefull,andtheapexbeatisprominentanddisplacedlaterally.
Heartsoundsareloud.Thesecondheartsoundiswidelysplit,andthe
pulmonarycomponentisoftenincreased.Ejectionsystolicmurmursareusually
present.Athirdheartsoundmaybeheard,butitspresencedoesnotimply
cardiacfailure.SignsofCHFarerare.Peripheraledema,pulmonaryrales,and
hepatomegalymaybesecondarytovenousstasis,pulmonarydisease,and
cholestasis,respectively,andthiscanconfusetheissue.
TheECGisnonspecific.Signsofleftventricularhypertrophyareusually
present.First-degreeatrioventricularblockandST-segmentandT-wavechanges
arecommon.Rightventricularhypertrophyisrarebutmightindicatesecondary
pulmonaryvasoocclusivediseaseandismorefrequentinolderpatients.Cardiac
enlargementandincreasedpulmonaryvascularmarkingsresemblingthoseseen
withaleft-to-rightshuntarethemostfrequentradiographicsigns.Pulmonary
infiltratesproducedbyinfarctionandinfectionmayalsobepresent.
Echocardiographicexaminationrevealsleftatrialandventriculardilationasa
resultofthevolumeoverloadofchronicanemia.Leftventricularcontractionis
oftenhyperdynamic.Mildmitralandtricuspidvalvarregurgitationarealsoseen
commonly.362
CHFismorecommoninadultsthaninchildren.Myocardialdysfunctionwith
anabnormalresponsetoexercisehasbeendemonstratedinchildren,particularly
iftheysufferfrompulmonaryhypertension.363Approximatelyone-thirdhave
pulmonaryhypertension,andthisriskprobablyincreaseswithage.364The
pulmonaryhypertensionismultifactorial,resultingfromtheeffectsofchronic
vasoocclusivedisease,increasedleftventricularfillingpressuresduetotheleftsidedchamberenlargement,andprobablyotherasyetundefinedeffectsof

vasculardysfunction.Thepresenceofpulmonaryhypertensiongreatlyincreases
long-termrisk.365Additionally,theriskofsuddendeathduringacutepulmonary
vasoocclusivecrisesisincreasedinthepresenceofpulmonaryhypertension,
probablysecondarytoacuteincreasesinpulmonaryvascularresistancerelated
tothecrisis.366Leftventriculardilationhasbeenshowntonormalizefollowing


thetransfusionofpackedredcells,furthersupportingthenotionthatcardiac
abnormalitiesarerelatedtochronicanemiaandnotspecifictosicklecellanemia
perse,althoughmicrovascularmyocardialdamagemaybeamanifestationof
subclinicalmyocardialdamageaspartofthesicklingprocess.367Ofcourse
chronictransfusioncanleadtothedepositionofiron,resultinginventricular
diastolicdysfunction,anditisunclearwhetherchelationtherapyiseffectiveat
preventingthiscomplication.368
Repairofcongenitalcardiacmalformationsiscomplicatedbythepresenceof
sicklecelldisease,ascardiopulmonarybypassandhypothermiccirculatory
arrestcanprecipitatevasoocclusivecrises.Mostrecommendapartialor
completeexchangetransfusionpriortotheinitiationofsurgery,with
optimizationofbloodgases,ratesofflow,andvolumes.Thesepracticesarealso
oftenemployedeveninpatientswithsicklecelltrait.Despitethiscommon
practice,therearereportsofsuccessfulcardiacsurgeryusingcardiopulmonary
bypasswithouttheuseofexchangetransfusion.369

AnorexiaNervosa
Anorexianervosaisalife-threateningdisorderinwhichaffectedindividuals
attempttoloseweightthroughstarvation,theuseoflaxatives,andexercise.It
affectsfemalesmoreoftenthanmalesandtypicallybeginsinadolescence.
Patientshaveadistortedbodyimageandfearofweightgain,maintaininga
weightlessthanfive-sixthsoftheiridealweight.Althoughthisdisorderaffects
allbodilysystems,itcarriesahighmortalityinpartduetoitseffectsonthe

cardiovascularsystem.Commonfindingsincludesinusbradycardia,reduced
volumes,anddiminishedventricularmassandcardiacoutput.370,371Despite
thesechanges,leftventricularcontractilityusuallyremainsnormal,372although
cardiomyopathyhasbeenreported.373QTprolongationisoftenseenontheECG
andmaybeduetoorexacerbatedbyhypokalemiaassociatedwiththedietary
derangements.Thisalsomayexplainsomecasesofsuddendeath.374Theprecise
etiologyofreductioninleftventricularmass,volume,andoutputremainstobe
elucidated.Itmaybeduetoatrophysecondarytomalnutritionortotheeffectsof
chroniclossofpreload.Refeedingcannormalizemanyofthecardiac
derangementsincludingsinusbradycardia,QTprolongation,andleftventricular
changes.375,376Nonetheless,refeedingbyitselfcanleadtosevere
cardiopulmonarycompromiseandmustbecarriedoutjudiciously.377


Summary
Theheartissusceptibletomanycongenitalandacquired,endogenousand
exogenous,insultsthatmaymodifyitsperformance.Carefulcardiacevaluation
shouldformpartoftheassessmentoftheseoftenmultisystemdisorders.
Conversely,unexplainedabnormalitiesofcardiacfunctionarerarelytruly
“idiopathic,”andsuchfindingsshouldleadtocarefulevaluationforthepresence
ofaunifyingunderlyingdisorder.Thisisimportantas,increasingly,specific
therapiesareavailablethatmayreverseorattenuateprogressionofthedisease
andassociatedcardiacproblems.