Download Congenital Heart Disease

Congenital Heart
Disease
CHD
CHD = Abnormalities of the heart or great
vessels present from birth
Most – faulty embryogenesis during the 3rd8th week when the CVS form and begin
functioning
Worst ones don’t survive to term
Those who do usually have only discrete
regions of the heart affected e.g. septal
defect or valvular defect
CHD
Dx
Some when change from fetal to postnatal
circulation
50% diagnosed by one year of life
Mild forms - adulthood
CHD
Incidence
1% of all live births
CV defects among most common malformations and are the most
common cause of heart disease in children
Higher in premies and stillborns
Table 12-2
VSD most common
Tetralogy of Fallot most common cyanotic
Many survive into adulthood - repairs
arrhythmias
additional surgery
ventricular dysfunction
use of prosthetics
risk of childbearing
CHD
Cardiac Development – figure 12-3
First heart field
TFs: TBX5, Hand1
Mainly LV
Second heart field
TF: Hand2, FGF=10
Outflow tract, RV, most of atria
Cardiac neural crest
Septation of outflow tract, aortic arches
CHD
ECM – swellings – endocardial cushions
Future valve development
Day 50 – 4 chambered heart
Signaling pathways regulating TFs
Wnt
VEgf
bone morphogenetic factor
TGF-beta
FGF
Notch
Heart – mechanical organ – exposed to flowing blood from earliest
stages – hemodynamic forces play a role
Specific micro RNAs – critical role- patterns and levels of TF
expression
CHD
AD mutations – partial loss of function in one
or more required factors, TFs usually
“The main known cause of CHD consist of
sporadic genetic abnormalities.”
single gene mutations
small chromosome deletions
additions or deletions of whole
chromosomes
Table 12-3
CHD
Heterozygotes = 50% reduction in activity =
deranged cardiac development
Factors work together- large protein
complexes – different single gene
mutations produce similar defects
Signaling pathways or structural roles
NOTCH1 – bicuspid AV
NOTCH2, JAGGED1 – TOF
Fibrillin – Marfan’s
CHD
DiGeorge Syndrome
Small deletion of 22q11.2 in 50%
4th branchial arch and 3rd and 4th pharyngeal pouches
Thymus, parathyroids, heart
TBX1
Chromosomal aneuploidies
Turner Syndrome
Trisomies 13,18, 21
21- most common genetic cause of CHD
endocardial cushion defects
CHD
First-degree relatives of affected patients are at increased
of CHD – subtle forms of genetic variation
Environmental factors?
+/- genetic factors
congenital rubella infection
gestational diabetes
exposure to teratogens
nutritional factors?
transient environmental stresses during 1st trimester?
CHD
Clinical features
Left-to-right shunts
Right-to-left shunts
Obstructive lesions
Shunt= abnormal communication between
chambers or vessels
Obstruction = narrowing (if completeatresia)
CHD
R to L
Hypoxemia
Cyanosis
Emboli bypass lungs – brain infarction,
abscess ( paradoxical embolism)
Clubbing (hypertrophic osteoarthropathy)
Polycythemia
CHD
L to R
Normally low-pressure, low-resistance pulmonary circulation now sees high flow
volumes and pressures
RVH
Atherosclerosis of pulmonary vessels
medial hypertrophy
vasoconstriction
irreversible obstructive intimal lesions
Pulm pressures reach systemic levels
R to L shunt
Eisenmenger Syndrome
Altered hemodynamics of CHD
Dilation, hypetrophy or both
Decreased volume and muscle mass – hypoplasia – before birth, atrophy –
postnatally
CHD
L to R
ASD
VSD
PDA
AV septal defects
CHD
ASD
abnormal, fixed opening in the atrial septum
usually asymptomatic until adulthood
3 types
Secundum (90%) – center of the septum
Primum (5%) –adjacent to the AV valves
Sinus venosus ( 5%) – SVC, associated with APVR
Clinical
L to R
Pulmonary blood flow -2-4 times normal
murmur from increased pulmonic valve blood flow
Surgical or catheter correction – low mortality, normal long-term
survival
PVO –oval fossa, 80% closed permanently, 20% potential opening that can become
clinically important r-to-l
CHD
VSD
Most common congenital anomaly
20-30% isolated finding
Most are associated with other cardiac anomalies
Classified by size and location
90% membranous
Rest are infundibular ( below the PV) or muscular
Muscular can be multiple ( “Swiss-cheese”)
Clinical
Large – problems from birth, RVH, pulmonary hypertension,
correct before irreversible changes
Smaller – well-tolerated
CHD
PDA
DA stays open, allowing L to R shunt from
aorta to pulmonary artery
90% isolated anomaly
“machinery-like” murmur
close as soon as possible to prevent irreversible
PH
Some congenital lesions are ductus dependent
and there by need to keep the DA opene.g. aortic atresia, use prostaglandin E)
CHD
AV septal defect
Complete atrioventricular canal defect
Partial – primum ASD with mitral
insufficiency
Complete – large combined AV septal
defect and a common AV valve – all 4
chambers communicate, all have
hypertrophy
1/3 have Down syndrome
Surgically correctible
CHD
R to L
Tetralogy of Fallot
Transposition of the Great Arteries
Truncus arteriosus
Tricupsid Atresia
Total Anomalous Venous Connection
CHD
Tetralogy of Fallot
4 cardinal features
VSD
Obstruction of the right ventricular outflow tract (subpulmonary stenosis)
An aorta that overrides the VSD
RVH
Embryoloigcally – anterosuperior displacement of the infundibular septum
“Boot-shaped” heart – marked apical RVH
Sometimes PVS, PV atresia
Sometines AV insufficiency, ASD
25% right aortic arch
Clinical – Classic TOF – r-to-l shunt
Pink TOF – l to r shunt because of mild subpulmonary stenosis
As child grows obstuction becomes worse
Stenosis protects pulmnary arteries from overload and RV failure rare because RV
decompressed by the VSD
CHD
TGA
Ventriuloarterial discord
Aorta from RV
PA from LV
Separation of the systemic and pulmonary
circulations – incompatible with life
unless a shunt exists VSD or PFO or PDA or
artificial shunt –balloon atrial septostomy
Surgical repair
CHD
TA
Failure of separation into the aorta and PA
a single vessel giving rise to the systemic,
pulmonary and coronary circulation
Associated VSD
CHD
TAPC
Pulmonary veins fail to join the left atrium
PFO or ASD
Aplastic Left atrium
LV normal size
CHD
Obstructive Congenital Anomalies
Coartation of the aorta
PS and atresia
AS and atresia
CHD
Coarctation of the Aorta
Males 2x females
Associated with Turner syndrome
2 classic types
“infantile” –
hypoplasia of the arch proximal to a PDA, symptomatic in
early childhood, cyanosis over lower half of body,
surgical correction needed early
“adult” –
discrete ridgelike infolding of the aorta, just opposite a
closed DA (ligamentum arteriosus) distal to the arch vessels,
hypertension in upper extremities, signs of arterial insufficiency in
lower, notching of the ribs due to collateral circulation
Clinical –
murmur with thrill
LVH
CHD
PS and atresia
Obstruction of the PV
Isolated or part of a more complex anomaly
RVH
Poststenotic dilation of PA
Complete obstruction- need shunt to survive
Mild – asymptomatic
Symptomatic – surgical correction
CHD
AS and atresia
Vavular-hypoplastic, dysplastic, decreased number
Subvalular-dense fibrous tissue below the cusps
Supravavular- aortic dysplasia, thickened and constricted, deletion
on chromosome 7, elastin gene, Williams-Beuren syndrome,
hypercalcemia, cognitive abnormalities, facial anomalies
Hypoplastic left heart syndrome – severe stenosis of atresia –
underdevelopment of LV and aorta – endocardial fibroelastosis
Clinical – systolic murmur, thrill, LVH, antibiotic prophylaxis for SBE,
avoid strenuous activity, sudden death