B4-048 CBCL Congenital Heart Defects Flashcards
if the abnormal O2 is first observed in the right ventricle, what is the defect?
VSD
if the abnormal O2 is first observed in the right atrium, where is the defect?
ASD
if the abnormal O2 is first observed in the pulmonary artery, what is the defect?
ductus arteriosus
in the absence of a cardiac shunt, cardiac output is equal to
pulmonary blood flow
in the presence of a cardiac shunt, the magnitude of the shunt is equal to
the difference between CO and pulmonary blood flow
calculation for cardiac output
septum between right and left atrium doesn’t close after birth
ASD
90% of ASD cases are due to a defect in
ostium secundum
comonly associated with fetal alcohol syndrome
4
- ASD
- VSD
- PDA
- TOF
10% of ASD is due to a defect in
also associated with 25% of down syndrome cases
ostium primum
acyanotic
left to right shunt
what type of shunt is ASD?
left to right
increased O2 sat in
* right atrium
* right ventricle
* pulmonary artery
ASD
splitting S2 due to delayed pulmonic valve closure
may also have systolic murmur
ASD
- embolism starts in right side but cross to left side of heart via defect
- can enter systemic circulation and cause stroke
paradoxical embolism
treatment: ASD
specify child vs. adult
- child: monitor, may close on own
- adult: surgery, patch opening
infant cases appear after the aortic arch but before the patent ductus arteriosus
coarctation of the aorta
- lower extremity cyanosis, weak pulses
- hypertension in upper extremities
coarctation of the aorta
increased risk of HF, cerebral hemorrhage, aortic rupture, and endocarditis
coarctation of the aorta
becomes ligamentum arteriosum
ductus arteriosus
keeps ductus arteriosus open
prostaglandin E2
associated with congenital rubella syndrome
3
- PDA
- ASD
- VSD
what kind of shunt is PDA?
left to right
continous, machine like murmur
PDA
uncorrected left to right shunt increases the pulmonary blood flow causing pulmonary arterial hypertension
eisenmenger syndrome
causes late cyanosis, clubbing, and polycythemia
associated with L to R shunt
eisenmenger syndrome
closes PDA, and inhibits PGE2
indomethacin
four abnormalities of TOF
- pulmonary stenosis
- RVH
- overriding aorta
- VSD
PROVe
boot shaped heart on CXR
TOF
caused by anterosuperior displacement of the infundibular septum
TOF
what kind of shunt is TOF?
right to left
most common cause of cyanotic CHD
TOF
associated with chr 22q11
DiGeorge
TOF
why does squatting (knee chest position) reduce cyanosis?
- kinks femoral artery
- increases TPR
- increases pressure in LV
- Left > Right
- shunt temporarily reverses
treat tet spell
crying, fever, and exercise exacerbates RV outflow obstruction
tet spell
TOF
what kind of shunt is TGA?
right to left
- aorta leaves RV
- pulmonary trunk leaves LV
results in complete separation of systemic and pulmonary circulation
TGA
not compatible with life unless a shunt is present
patent foramen ovale/PDA, or VSD
TGA
due to failure of the aorticopulmonary septum to spiral
TGA
fails to divide into pulmonary trunk and aorta due to failure of aorticopulmonary septum formation
persistent truncus arteriosus
what kind of shunt is PTA?
right to left
majority caused by defect in membranous septum
VSD
holosystolic murmur at lower left sternal border
VSD
larger VSDs can cause
3
- pulmonary hypertension
- HF
- Eisenmenger’s syndrome
associated with maternal diabetes in pregnancy
3
- TGA
- PTA
- VSD
pansystolic murmur noted after the first month of life
VSD
blood O2 content greater in right ventricle than in the right atrium
indicates…
left to right shunt [VSD]
the magnitude of the shunt is equal to
cardiac output - pulmonary blood flow
complications of ASDs
4
- cyanosis
- RVH
- righ HF
- paradoxical emboli
what additional defect is associated with TGA?
ventricular septal defect
- machine-like murmur best heard at the left suprasternal notch
- cyanosis of toes but not fingers
patent ductus arteriosus
hypertension in upper extremities and hypotension in legs
coarctation of the aorta
the clinical outcome of TOF is dependent on
severity of stenosis
O2 content in pulmonary artery greater than the RV
PDA
O2 content in RV greater than RA
VSD
- present about 6 weeks of life
- tachypnea
- poor feeding
- growth retardation
- sweating
atrioventricular canal defect
up to 40% of individuals with Down syndrome have […] defects
atrioventricular canal
elevated upper extremity blood pressure and reduced lower extremity blood pressure
coarctation of the aorta
machine like murmur
cyanosis of toes
PDA
if the patient has a regular rhythm, heart rate can be calculated from EKG by
counting R-R intervals
divide from 300
in left axis deviation, the QRS complex will have a positive net deflection in […] and a negative deflection in […]
lead 1 positive
lead aVF negative
- positive net deflection in lead 1
- negative net deflection in lead aVF
left axis deviation
risk of inheritance in autosomal dominant disorder
50%
risk of inheritance in autosomal recessive disorder
25%
what promotes hypertension in coarctation of the aorta?
dimished renal blood flow triggers RAAS
pulse differential from upper and lower extremities
coarctation of the aorta
- most common type of ASD
- occurs in middle of the wall between the atria
defect in septum secundum
puppy break
ASD defect that occurs in the upper part of atrial septum
rare
defect in sinus venosus
ASD defect occurs in part of the wall between the coronary sinus and left atrium is missing
defect in coronary sinus
cyanosis of the lower extremities but not the upper body
differential cyanosis
- elevated arterial pressure in arms and head arteries
- much lower arterial pressure in lower extremities
coarctation of the aorta
blood O2 content in pulmonary artery greater than right ventricle
PDA
due to shunting
O2 content increased in right atrium compared to systemic veins
ASD
- harsh continous murmur heard at left sternal border
- arterial blood oxygen content higher in right hand than left foot
PDA
- tachycardia
- dyspnea
- continous murmur
- cardiomegaly
- differential cyanosis
PDA
increased pulmonary resistance leads to reversal of shunt and corresponding cyanosis
Eisenmenger’s syndrome
- manifests a few weeks after birth
- pansystolic/holosystolic murmur at left sternal border
- higher than expected oxygen in right ventricle
VSD
defects associated with TOF
4
- Pulmonary stenosis
- RVH
- Overriding aorta
- VSD
PROVe
what causes the closure of the foramen ovale at birth?
- higher pressure in the left atrium compared to right atrium
- caused by venous return from pulmonary veins and dilation of pulmonary arterioles
at birth, the vascular pressure […] and left atrial pressure […] the right
decreases; exceeds
forces septum primum against the secundum, closing foramen ovale
neural crest cells are key to the formation of
membranous IV septum
ejection fraction equation
EDV-ESV/EDV
CO equation from Fick principle
oxygen consumption/(arterial O2 content- mixed venous O2 content)
label the chambers of the heart on this apical view
use of ultrasound to define cardiac structures
echocardiography
in the apical 4 chamber view, the right heart is on what side of the image?
left
