module 10 congenital heart defects Flashcards
circulation in utero
fetal pulmonary vascular resistance HIGH
systemic resistance low
placenta is the site of gas exchange
Birth and circulation
gas exchange shifts to lungs pulmonary resistance decreases systemic resistance increases Closure of foramen ovale: 1st month Closure of ductus arteriosis: 10-21 days
foramen ovale
opening between RA and LA
ductus arteriosus
connects pulmonary artery and aorta
congenital heart defects
may be attributed to
- maternal rubella during first trimester
- exposure to cardiac teratogens
- genetic influences
result in 2 primary pathologic processes
- shunting of blood through abnml pathways
- obstruction of blood flow d/t narrowing
shunting of blood
left to right: acyanotic -> inc. workload on R. side of heart -> RV hypertrophy -> inc. Right sided pressure --- possible switching to a right to left shunt right to left: cyanotic
obstructive
stenosis or atresia: failure of valves to develop
coarctation of aorta: narrowing
acyanotic congenital defects
desorders that result in left to right shunting
- atrial septal defect
- ventricular septal defect
- patent ductus arteriosus
- coarctation of the aorta
- pulmonary and aortic stenosis or atresia
ASD atrial septal defect
foramen ovale did not close -> inc. pulmonary blood flow -> inc. right side hypertrophy small defects may be asymptomatic for years long term: - pulmonary HTN - RV hypertrophy - possible reversal of shunt to a right to left pattern
VSD ventricular septal defect
commonly associated w/ other cardiac defects
initially left to right w/ inc. pulmonary flow
-> RV hypertrophy -> reversal of shunt
systolic murmur
PDA patent ductus arteriosis
ductus arteriosis does not close nml closure 1-2 days after birth -blood from aorta -> pulmonary artery - can close spontaneously -- prostaglandin inhibitors can induce closure - harsh systolic murmur - systolic thrill - can lead to pulmonary hyperTN -> RSHF -> reversal of shunt
COA coarctation of the aorta
narrowing of the aorta
rarely happens by self
males > females 3-4x
can occur anywhere in aorta but usually close to ductus arteriosus
- preductal: more severe
-> lower blood flow maintained by ductus arteriosus -> RSHF
- postductal: less severe
Upper extremity: Inc. BP
Lower extremity: Dec. BP and weak pulses
systolic murmur
ventricular hypertrophy
pulmonary stenosis/atresia
No communication between RV and lungs
- blood must go through septal opening then through ductus arterisosus
- RV hypoplasia
- ASD large
- mild-severe: depends on narrowing of pulmonic valve
- RV hypertrophy secondary to high afterload caused by narrow opening
Aortic stenosis/ atresia
rare not compatible with life correctable with good prognosis Inc. LV afterload r/t small opening systolic murmur
cyanotic congenital defects
result in right to left shunting
- Tetralogy of Fallot
- transposition of great arteries
- truncus arteriosus
- tricuspid atresia
Tetralogy of Fallot
4 characteristic abnormalities
- overriding aorta: above VSD
- VSD
- RV hypertrophy
- Pulmonary stenosis
Enlarged heart r/t extensive RV hypertrophy
Aorta receives unoxygenated blood and oxygenated blood
transposition of great arteries
aorta arises from RV, and pulmonary artery from LV.
- 2 separate non-communicating circulations
- unless there are septal defects for mixing
- not compatible with life
truncus arteriosus
pulmonary artery and aorta do not separate
- > one large vessel
- Large VSD
- Single valve over both ventricles
- amount of blood entering pulmonary vs systemic circulation depends on vascular resistance.
- inc. pulmonary blood flow -> pulm. HTN -> RV hypertrophy -> inc. pulm resistant -> cyanosis as blood enters systemic circulation instead of pulmonary
tricuspid atresia
absence of tricuspid valve, underdevelopment of RV, and septal defect
- blood bypasses RV
patent ductus arteriosus needed to perfuse lungs
- cyanosis at birth
Kawasaki disease
mucocutaneous lymph node syndrome
- acute self-limiting systemic vasculitis that may result in cardiac sequelae
- immune system attacks arteries
- endothelial cells attacked -> exposed underlying tissue
- inc. risk of thrombus -> ischemia
- weak artery walls -> aneurysm
- fibrin in walls -> thick vessel walls -> dec. function
- 5 y/o or younger
- males > females
s/s of kawasaki disease
conjunctivitis rash adenopathy strawberry tongue: top layer sluffs off hand and feet swelling/ rash 5 or more days of high fever "CRASH burn"
systemic HTN in peds
often have underlying disease - renal disease - COA - adrenal tumors - space occupying lesions of cranium defined by SBP and DBP >95th percentile for age and gender on 3 occasions
