Fung > congenital heart disease Flashcards
what is “congenital heart disease”?
general term used to describe abnormalities of the heart & great vessels that are present from birth
when do congenital heart defects occur?
during week 3 & 8 of gestation (faulty embryogenesis)
how many births (%) have a congenital CV defect?
1%
what is the most common form of CV disease among children?
congenital CV defects
what are the 2 classes of causes of congenital heart disease?
sporadic genetic abnormalities
AND
environmental factors
what are the 3 types of sporadic genetic abnormalities that cause CHD?
single gene mutation
small chromosomal deletions
tri/monosomies
what are the tri & monosomies that can cause CHD?
turner syndrome (XO) trisomy 13 trisomy 18 (edward) trisomy 21 (down)
what are the environmental factors that cause CHD?
congenital rubella
gestational diabetes
teratogens
what is a shunt?
abnormal communication btwn chambers or BVs
what is an atresia?
a complete obstruction btwn chambers or BVs
what are the 3 primary categories of CHD?
L to R shunt
R to L shunt
obstruction
what happens to blood in R>L shunts?
poorly oxygenated venous blood mixes w/ systemic arterial blood
how do pts w/ R>L shunt present?
hypoxemia & cyanosis (cyanotic congenital heart disease)
what are 2 clinical features of R>L shunts?
clubbing of fingers & toes (hypertrophic osteoarthropathy)
AND
polycythemia
what are the clinical situations assoc w/ R>L shunt?
tetralogy of fallot
transposition of great vessels
persistent truncus arteriosus
tricuspid atresia
total anomalous pulmonary venous connection
paradoxical embolism
what are the 4 cardinal features of tetralogy of fallot?
ventricular septal defect
subpulmonary stenosis
overriding aorta
R ventricular hypertrophy
T/F: in tetralogy of fallot, the ventricular septal defect is small
FALSE
normally large
what is subpulmonary stenosis?
obstruction of the R ventricular outflow tract
what is overriding aorta?
aorta forms the superior border of the VSD & therefore overrides the defect of both ventricles
what does tetralogy of fallot result from?
anterosuperior displacement of the infundibular septum
T/F: pts always die of tetralogy of fallot
false
can survive into adulthood even untreated
what are the clinical consequences of tetralogy of fallot dependent on?
degree of subpulmonic stenosis
what does mild subpulmonic stenosis resemble?
isolated VSD
acts more like a L>R shunt w/o cyanosis
what characterizes severe tetralogy of fallot?
greater resistance to RV outflow & R>L shunt
hypoplastic pulmonary arteries & aortic dilation
what is classic tetralogy of fallot?
severe
what is pink tetralogy of fallot?
mild
how do pts w/ tetralogy of fallot present at birth?
cyanotic
can you repair tetralogy of fallot?
yes complete surgical repair is possible
in transposition of the great vessels, where does the aorta come from?
R ventricle
in transposition of the great vessels, where does the pulmonary artery come from?
L ventricle
T/F: in transposition of the great vessels, the aorta is in front of the pulmonary artery
TRUE
this is the opposite of normal
(whatever vessel comes from the R ventricle goes in front, so normally that’s the pulmonary artery, but in transposition, it’s the aorta)
why does transposition of the great vessels occur?
abnormal formation of the truncal & aortopulmonary septa
what does the outcome of transposition depend on?
degree of blood mixing (via shunt)
magnitude of tissue hypoxia
ability of RV to maintain systemic circulation
what are the possible shunts in transposition?
VSD
patent foramen ovale
ductus arteriosus
which shunts are unstable in transposition?
patent foramen ovale & ductus arteriosus
which shunts are stable in transposition?
VSD
which shunts happen more in transposition?
PFO & ductus arteriosus: 65%
VSD: 35%
what do you do w/ pts that have an unstable shunt in transposition?
balloon atrial septostomy
what are the clinical features of transposition?
R ventricular hypertrophy
atrophic L ventricle
T/F: w/o surgery, most transposition pts live to 5 yo
FALSE
w/o surgery, most die w/i first months of life
how long can pts w/ transposition live if they get surgery?
into adulthood
why does persistent truncus arteriosus happen?
failure of separation of the embryologic truncus arteriosis into the aorta & pulmonary artery
what is persistent truncus arteriosus?
single great vessel receives blood from both ventricles & coronary circulation
why is there a danger of irreversible pulmonary HTN w/ persistent truncus arteriosus?
associated VSD that produces systemic cyanosis & increased pulmonary blood flow
what is tricuspid atresia?
complete obstruction of the tricuspid valve orifice
why does tricuspid atresia happen?
unequal division of the AV canal
what does tricuspid atresia result in?
enlarged mitral valve
underdeveloped R ventricle
how do the L ventricle & pulmonary artery communicate in tricuspid atresia?
R>L shunt thru atria (ASD, PFO) & a VSD arises from hypoplastic R ventricle
how do babies w/ tricuspid atresia look?
cyanosis
high mortality rate
what happens in total anomalous pulmonary venous circulation (TAPVC)?
pulmonary veins fail to join the L atrium
why do you get TAPVC?
failure of development (atresia) of common pulmonary vein
during fetal life, where do the primitive systemic venous channels drain from & to?
from the lung
into left innominate vein or coronary sinus
how does venous blood enter the atrium in TAPVC?
PFO or ASD
what are the clinical features of TAPVC?
volume & pressure overload >>> hypertrophy & dilation of R heart
dilation of pulmonary trunk
hypoplastic L atrium
possible cyanosis d/t R>L shunt of ASD
what do L>R shunts increase?
pulmonary blood flow & volume
T/F: pulmonary circuit is usu low flow, high resistance
FALSE
low flow, low resistance
what is the first response to increased blood flow in a L>R shunt?
medial hypertrophy vasoconstriction to maintain distal pressures & prevent pulmonary edema
what does prolonged increased pulmonary vasoconstriction in L>R shunt induce?
obstructive intimal lesions (hyaline & hyperplastic arteriosclerosis)
what happens w/ pulmonary vascular resistance in a L>R shunt?
it reaches systemic levels & converts the L>R shunt to a R>L shunt
what is the L>R to R>L reversal called?
late cyanotic CHD or Eisenmenger syndrome
after the irreversible pulmonary HTN develops, can you still repair the structural defects of CHD?
NOPE
what are 3 examples of L>R shunts?
ASD
VSD
PDA
what is ASD?
abnormal fixed opening in the atrial septum
what causes ASD?
incomplete tissue formation that allows communication of blood btwn L & R atria
are PFO & ASD the same thing?
nope
what are the 3 types of ASD?
secundum
primum
sinus venosus
what is the most common type of ASD?
secundum: 90%
primum: 5%
sinus venosus: 5%
what is ASD secundum?
results from deficient or fenestrated oval fossa near center of atrial septum
where does ASD primum occur?
adjacent to AV valves
where does ASD sinus venosus occur?
near the entrance of the SVC
what is ASD sinus venosus assoc w/?
anomalous pulmonary venous return to the R atrium
what are the clinical features of ASD?
L>R shunt d/t lower pulmonary vascular resistance & greater R ventricle distensibility
MURMUR d/t inc pulmonary blood flow
no sx before 30 yo
T/F: irreversible pulmonary HTN is common w/ ASD
FALSE
it’s unusual
how do you prevent complications w/ ASD?
surgical or catheter-based repair
what are 3 complications of ASD?
heart failure
paradoxical embolization
irreversible pulmonary vascular disease
what is the foramen ovale?
it’s a small hole in the atrial septum at the oval fossa that allows oxygenated blood from the placenta to bypass the lungs in the fetus
what happens to the foramen ovale after birth?
it is forced shut d/t increased BP on the L heart in 80% of ppl
in 20% of people where the foramen ovale doesn’t close, what happens in times of increased R sided pressure?
the flap opens & can create a R>L shunt
what can cause increased R sided pressure?
bowel movement
coughing
sneezing
T/F: there is a small possibility of paradoxical embolism w/ PFO
TRUE
what is the most common form of congenital cardiac anomaly?
VSD
how many VSDs occur in isolation?
20-30%
most are assoc w/ another congenital anomaly
how do you classify VSD?
size & location
what type of VSD is most common?
membranous (90%)
what are VSDs below the pulmonary valve called?
infundibular VSD
what is a swiss cheese septum?
sometimes multiple VSDs w/i the muscular septum
what do the clinical manifestations of VSD depend on?
size & assoc R-sided malformation of the VSD
what happens w/ a small VSD?
well-tolerated
may close spontaneously
what happens w/ a large VSD?
difficulties from birth
significant L>R shunting
a large VSD is usually what type?
membranous or infundibular
do you have to correct large VSDs?
YES
early!
what is the purpose of the ductus arteriosus in a fetus?
shunts blood from the pulmonary artery to the aorta
what happens in PDA?
the ductus arteriosus doesn’t close spontaneously after birth
does PDA produce a murmur?
YES
harsh, machine-like
what % of PDAs are isolated?
90%
10% are assoc w/ coarctation of the aorta or pulmonic or aortic valve stenosis
what do clinical features of PDA depend on?
diameter & CV status
T/F: PDA pts are asymptomatic at birth
TRUE
what type of PDA does NOT affect a child’s growth & development?
narrow
what can a larger PDA lead to?
Eisenmenger syndrome
starts as L>R shunt though
when should the PDA be closed?
early in life
how can you keep a PDA open?
prostaglandin E
what is another name for atrioventricular septal defect?
atrioventricular canal defect
how does AVSD happen?
embryologic failure of the superior & inferior endocardial cushions of the AV canal to fuse adequately
how does AVSD manifest?
incomplete closure of the AV septum
malformation of tricuspid & mitral valves
what are the 2 forms of atrioventricular septal defect?
partial & complete
what is partial AVSD?
primum AVSD & cleft anterior mitral leaflet > mitral insufficiency
(idk what any of this means)
what is complete AVSD?
large combined AVSD + large common AV valve
what is a large common AV valve?
a big hole in the center of the heart
what happens in complete AVSD?
all 4 chambers communicate so you get volume hypertrophy
1/3 of complete AVSD pts have what disorder?
down syndrome
can you repair AVSD?
yes
surgical repair is possible
what are the 3 types of obstructive congenital heart disease?
coarctation of the aorta
aortic valvular stenosis
pulmonary valvular stenosis
T/F: coarctation of the aorta is rare
FALSE
it’s a common structural abnormality
what disorder is coarctation of the aorta assoc w/?
turner syndrome (XO)
what are the 2 forms of coarctation?
infantile
adult
what is infantile coarctation?
tubular hypoplasia of the aortic arch proximal to PDA
are pts w/ infantile coarctation symptomatic?
yes
right after birth (slide 32)
in early childhood (slide 31)
what is adult coarctation?
discrete ridgelike infolding of the aorta opposite of closed ductus arteriosus (ligamentum arteriosum) distal to arch vessels
what does the clinical manifestation of coarctation depend on?
severity of narrowing of the lumen
patency of ductus arteriosus
what happens if you don’t surgically intervene w/ infantile coarctation?
high mortality rate
why does infantile coarctation cause lower extremity cyanosis?
delivery of unsaturated blood thru the PDA
T/F: the adult form of coarctation is immediately life-threatening
false
children may go unrecognized until adulthood unless severe
what are the sx of adult coarctation?
upper extremities: HTN
lower extremities: weak pulses, hypotension, claudication, coldness
Notching on radiograph
what causes the Notching on radiograph of adult coarctation?
development of collateral circulation btwn pre & post coarctation arteries via enlarged intercostal & internal mammary arteries
is surgical repair of adult coarctation possible?
yes
T/F: pulmonary stenosis is common
TRUE
T/F: pulmonary stenosis is always isolated
false
may be isolated or may be part of a syndrome (TOF, TGA)
what is the result of pulmonary stenosis?
right ventricular hypertrophy
what is the difference btwn mild & severe pulmonary stenosis?
mild can be asymptomatic
severe requires surgical repair
what is pulmonary atresia?
no communication btwn R ventricle & lungs
what are the results of pulmonary atresia?
hypoplastic R ventricle
ASD
how does blood reach the lungs in pulmonary atresia?
PDA
where can the aorta narrow?
valvular
subvalvular
supravalvular
what are the cusps like in valvular aortic stenosis/atresia?
may be hypoplastic, thickened, nodular, or abnormal in number
what causes subvalvular aortic stenosis/atresia?
thickened ring or collar of dense endocardial fibrous tissue BELOW the cusps
what is subvalvular aortic stenosis/atresia assoc w/ clinically?
prominent systolic murmur
what is the result of subvalvular aortic stenosis/atresia?
pressure hypertrophy of the L ventricle
how do you manage mild aortic stenosis?
conservatively w/ abx to prevent endocarditis
what is supravalvular aortic stenosis/atresia an inherited form of?
aortic dysplasia
what happens to the ascending aorta in supravalvular aortic stenosis/atresia?
it is thickened > causes luminal constriction
what does severe aortic stenosis/atresia cause?
obstruction to L ventricular outflow
hypoplasia of L ventricle & ascending aorta
what is another name for severe aortic stenosis/atresia?
hypoplastic left heart syndrome
what do you NEED to live w/ severe aortic stenosis/atresia?
PDA
T/F: You can live w/ severe aortic stenosis/atresia w/ no repair
FALSE
nearly always fatal unless surgically repaired
in what percentage of people does the foramen ovale stay open/patent?
20%
what is this?
tricuspid atresia
what is this?
transposition of the great vessels
what is this?
tetralogy of fallot
what is this?
patent foramen ovale
what is this?
persistent truncus arteriosus
what is this?
TAPVC
