Cardiac Embryology and congenital heart disease III Flashcards
Define
tetralogy of Fallot
cyanotic heart disease
1) RV outflow tract obstruction
2) RVH
3) dextraposition of aorta (aorta overrides VSD)
4) VSD
monology of Fallot
anterior and superior deviation of infundibular portion of ventricular septum
most common cyanotic defect
tetralogy of fallot
physiology of Tetralogy of fallot
1) VSD is large so RV and LV pressures equal)
magnitude of pulmonary blood flow in tetralogy of fallot determined by (4) things
1) source of pulm blood flow
2) severity of RV outflow obstruction
3) balanced RV and LV pressure
4) ductus arteriosus
source of pulm blood flow
1) antegrade RV output to pulm arteries
2) ducts arteriosus flow
if outflow obstruction is severe, most PBF derived from ___
ductus arteriosus
size of ducts primary determinant of PBF magnitude
What happens in RV outflow obstruction
1) narrowing of infundibular region
2) stenosis of pulm valve
what determines R–> L shunt with RV outflow obstruction
if RV outflow resistance HIGHER THAN SYSTEMIC VASCULAR RESISTANCE –> cyanosis
what determines L –> R shunt with RV outflow obstruction
if RV outflow resistance LESS THAN SYSTEMIC VASCULAR RESISTANCE –> no cyanosis
which shunt has cyanosis
R–> L shunt
which shunt occurs if RV outflow resistance greater than systemic vascular resistance
R–> L shunt
what are tet spells
hypoxic or hypercyanotic spells
when do tet spells occur
2-6 y/o
Different mechanisms of Tet spells
1) infundibular spasm –> decr PBF
2) decr venous return to heart –> decr RV pressure –> decr PBF
3) decr SV –> incr R to L shunt –> decr PBF
what can precipitate tet spells
1) prolonged crying
2 anemia
3) dehydration
exam of tet spells
1) BLUE
2) decr murmur intensity
3) altered consciousness/seizures
treatment of tet spells
INCREASE PULM BLOOD FLOW
1) knee chest position
2) phenylephrine
3) morphine for sedation
4) volume expansion with IV fluids
prevention of tet spells
beta blockers (propranolol) –> decr infundibular obstruction
what does clinical presentation of tetralogy of fallot depend on (3)
1) size of VSD
2) severity of RV outflow obstruction
3) SVR level
how does tetralogy of fallot present
BLUE BABY WITH LOUD MURMUR
HOW CAN CYANOSIS IN tetralogy of fallot worsen?
as ductus arteriosus closes
if a patient with tetralogy of fallot had severe RV outflow tract obstruction how do you treat
pt may have ductal dependent pulm blood flow
need prostaglandins or early surgical repair
how to diagnosis tetralogy of fallot
1) tachycardic and cyanotic if blue tet
2) diaphoretic and tachypneic if pink tet
3) precordial impulse displaced to left lower sternal border –> RV dominance
murmur of tetralogy of fallot
2-3/6 short systolic murmur of pulmonary stenosis
ecg of tetralogy of fallot
Right axis deviation
RVH
prevention of tetralogy of fallot
elective surgical repair at 2-4 month before tet spell risk inca
progression of tetralogy of fallot
if no intervention
1) if RV outflow tract obstruction severe and pt has ductal dependent pulm blood flow
- -> DEATH AT TIME OF DUCTAL CLOSURE w/o intervention
progression of tetralogy of fallot
if yes intevention in adulthood
1) cyanotic
2) clubbing of fingers
3) poorly develop enamel/teeth
4) incr bleeding
5) decr exercise tolerance (squat with exercise)
6) arrhythmia
why do tetralogy of fallot patients squat
to incr SVR
and incr pulm blood flow
known complication of unrepaired cyanotic congenital heart disease
cerebral abscess
after 1.5-2 y/o
symptoms of cerebal abscesses
persistent unexplained fever
behavioral changes
define coarctation of aorta
narrowing of aortic lumen
theories of coarctation of aorta
1) extension of ductal tissue into aortic arch
1) disturbance of subclavian artery migration
1) altered blood flow in fetus –> decr blood thru isthmus
15% of ____ patients have coarctation
TURNER’S SYNDROME
15% OF TURNER’S PATIENTS HAVE ___
coarctation
anatomy of coarctation
1) intraluminal projection of a “shelf” from lateral, posterior, anterior wall of aorta in area of ductus arteriosus
consequences of poor descending aorta perfusion
1) decr blood to bowel –> necrotizing enterocolitis
2) decr blood to leg muscles –> claudication with exercise
3) decr blood to kidneys –> incr RAAS activ, rebound hypertension after repair
clinical presentation of coarctation
general
1) asymptomatic as newborn (PDA allows adeq post-coarct flow)
2) as ductus closes –> tachypnea, diaphoresis, poor feeding
- -> cardiac failure
clinical presentation of coarctation
infancy
lack femoral pulses
cardiac failure/shock
clinical presentation of coarctation
childhood
asymptomatic
or
systemic HTN
intermittent lower extrem claudication and HA
clinical presentation of coarctation
adult
systemic HTN
diagnosis of coarctation
1) tachycardia
2) BP differential btwn Lower and Upper extrem
3) rales +/- hepatomegaly
heart sounds with coarctation
1) accentuated S2 or S3
2) soft systolic murmur
3) systolic click over apex if assoc bicuspid aortic valve
diagnosis of coarctation
1) absent or weak femoral pulses
2) ecg
3) CXR
ecg with coarctation
infants
Right axis deviation
RVH
ecg with coarctation
children
incr in LV forces
ecg with coarctation
adults
ST depression
T wave flattening/inversion
CXR with coarctation
normal after birth
signs of cardiac failure
1) cardiomegaly
2) prominent pulm arterial markings
3) pulm edema
echo with coarctation
site and severity of obstruction
presence of ductus (difficult to dx with large ductus
assoc bicuspid
VSD
aortic/subaortic senosis
management of coarctation
infants
1) maintain on prostaglandins until surgery
2) end to end anastomosis surgical repair
3) risk of recoarctation and aneurysm long term
management with coarctation
young children
balloon angioplasty vs surgery
management with coarctation
adults
surgery vs stent placement
progression of coarctation
1) develop collaterals with marked obstruction
- weak delayed femoral pulses compared to arm pulses
2) BP differential variable
- usually arm BP more increased
- young children slightly lower leg BP
consequences of coarctation (cause of death)
1) heart failure
2) aortic rupture/dissection
3) infective endocarditis
4) cerebral hemorrhage
monology of Fallot
“simplified tetrology of Fallot”
anterior and superior deviation of infundibular portion of ventricular septum
–> forms subpulmonary outflow tract
what causes a pink baby
blood left to right across VSD
depends on amt of blood thru RV outflow tract
what causes a blue baby
blood right to left across VSD
when do tet spells occur
2-6 months
Different mechanisms of Tet spells
1) infundibular spasm –> incr blood across VSD –> decr PBF
2) decr venous return to heart –> decr RV pressure –> decr PBF
3) decr SV –> incr R to L shunt –> decr PBF
what can precipitate tet spells
1) prolonged crying
2 anemia
3) dehydration
exam of tet spells
1) BLUE
2) decr murmur intensity (b/c less blood across pulm valve and go across VSD)
3) altered consciousness/seizures
treatment of tet spells
INCREASE PULM BLOOD FLOW
1) knee chest position (incr SVR)
2) phenylephrine (incr SVR)
3) morphine for sedation
4) volume expansion with IV fluids
prevention of tet spells
beta blockers (propranolol) –> decr infundibular obstruction
what does clinical presentation of tetralogy of fallot depend on (3)
1) size of VSD
2) severity of RV outflow obstruction
3) SVR level
how does tetralogy of fallot present
BLUE BABY WITH LOUD MURMUR
HOW CAN CYANOSIS IN tetralogy of fallot worsen?
as ductus arteriosus closes
if a patient with tetralogy of fallot had severe RV outflow tract obstruction how do you treat
pt may have ductal dependent pulm blood flow
need prostaglandins or early surgical repair
what is the 3 sign on CXR
when do you see?
why not in infants
SEEN IN ADULTS
1) dilated aortic knob
2) coarctation
3) post-stenotic dilation
rib notching from dilated intercostal arteries
not in infants b/c thymus so large
