101714 congenital heart disease cases

Question 1

hypoplastic left heart syndrome

Answer 1

left ventricle hypoplasia with mitral/aortic atresia

Question 2

why do fetuses with hypoplastic left heart syndrome do well?

Answer 2

because of the ductus arteriosus

after birth, doesn’t do well–needs surgery

Question 3

when would cardiogenic shock present in a pt with hypoplastic left heart syndrome

Answer 3

when the PDA is nearly fully closed

Question 4

pathophysiology of aortic coarctation

Answer 4

obstruction to flow causes increased LV afterload, resulting in increased wall stress leading to compensatory ventricular hypertrophy leading to congestive heart failure leading to shock/metabolic acidosis/organ failure

Question 5

fetal flow pattern for aortic coarctation

Answer 5

blood flow through aortic isthmus is only 10% of the total CO in FETAL period

ductal flow is right to left

R heart carries 2/3 of the volume load of total CO

even if isthmus was completely atretic, there would be blood supply to all tissues, so the fetus does well

Question 6

genetic influences for aortic coarctation?

Answer 6

Turner XO syndrome

Noonan syndrome

Question 7

what intracardiac lesion can aortic coarctation be associated with?

Answer 7

bicuspid aortic valve

Question 8

common presentations of aortic coarctation

Answer 8

fetal cardiac abrnomalities
infant with CHF
child with arterial systolic HTN
child with murmur

Question 9

how does aortic valve develop?

Answer 9

from 3 swellings of subendocardial mesenchyme

albnormal cavitation of these swellings results in leaflet fusion and stenosis

Question 10

aortic valve disease is progressive: true or false

Answer 10

true, due to calficication and fibrosis of valve leaflets, and aortic insuff may develop due to annular dilation

Question 11

what is the classic aortic valve stenosis murmur

Answer 11

harsh systolic crescendo-decrescendo murmur heard at R upper sternal border and radiating into neck

Question 12

effect of mild to moderate aortic stenosis on fetal circulation and postnatal?

Answer 12

no effect on fetus

postnatal: normal

Question 13

severe aortic stenosis-effect on fetal circulation and postnatal?

Answer 13

fetus: increased LVEDP, which reduces flow of highly oxygenated blood from umbilical vein into the LV and into the ascending aorta. umbilical venous blood high in O2 is instead directed through the RV where it mixes with SVC blood which is low in O2 and then is directed through ductus arteriosus into descending aorta and retrograde into ascending aorta (results in blood lower in O2 supplying brain and coronary arteries)

postnatal-dependent on ductus arteriosus for sytemic blood flow

Question 14

what is the most common genetic association for tetrology of fallot?

Answer 14

DiGeorge syndrome

Question 15

the most common cyanotic congenital heart disease

Answer 15

tetralogy of fallot

Question 16

what is seen more commonly in infants of diabetic mothers?

Answer 16

TGA

Question 17

what causes TGA?

Answer 17

probably abnormal conotruncal rotation as septation occurs

Question 18

what happens with TGA at birth?

Answer 18

marked cyanosis-degree can be variable depending on associated lesions, however. but it is usually profound

Question 19

what are potential sources of intercirculatory mixing for TGA?

Answer 19

atrial (PFO, ASD)
ventricular level (VSD-present in 40 % of TGA)
arterial level (PDA)

Question 20

postnatal circulation-what happens to SVR and PVR?

Answer 20

SVR increases
PVR decreases (with ventilation)

Question 21

difference btwn shunting and mixing?

Answer 21

shunting creates a route,

however, mixing requires perhaps more than just one route for effective distribution

Question 22

O2 rich blood from placenta enters umbilical vein to ductus venosus with preferential flow through what structure in heart in the fetal circulation?

Answer 22

PFO

Question 23

in terms of outputs, RV and LV have what percentages in fetal circulation?

Answer 23

RV-60

LV-40

Question 24

transition from fetal to newborn circulation is described by what?

Answer 24

parallel flow becomes flow in series

Question 25

why does the fossa ovale valve close after birth?

Answer 25

because all the RV output is now going to the lungs, which increases LA flow. the pressure in LA causes fossa ovale to close

Question 26

in newborn, if ductus arteriosus remains open, what happens circulation wise

Answer 26

pulmonary resistance drops. pressure in aorta becomes becomes a lot higher than pressure in pulmonary artery. blood flows from aorta to PA. can lead to heart failure and poor growth

Question 27

if newborn has a PDA but blood continues to flow from PA to aorta, how would you recognize this?

Answer 27

baby’s legs would be blue

Question 28

in order for hypoplastic left heart syndrome baby to survive after birth, what 2 additional defects must exist?

Answer 28

atrial septal defect and patent ductus arteriosus

Question 29

what cardiac defect is present in 40% of pts with Down syndrome

Answer 29

AVSD

Question 30

fusion of superior and inferior endocardial cushions result in what

Answer 30

division of AV canal into right and left AV orifices

also participate in formation of membranous portion of interventricular septum and closure of primum septum

Question 31

single S2?

Answer 31

suggests possibly one outflow tract

Question 32

after birth, what problems do you get with truncus arteriosus?

Answer 32

as pulmonary vascular resis decreases, blood flow prefers to go to lungs–can lead to heart failure or pulmonary overcirculation

Question 33

how can truncus arteriosus present?

Answer 33

increased or decreased pulmonary blood flow

decreased pulmonary blood flow and no regurgitation is a rare presentation

Question 34

heart failure symptoms in baby

Answer 34

tachypnea
hepatomegaly
poor feeding
diaphoresis

Question 35

truncus arteriosus -40% is associated with?

Answer 35

DiGeorge syndrome

Question 36

second most common congen heart defect

Answer 36

ASD

Question 37

exam finding for ASD?

Answer 37

fixed splitting of S2 b/c RV is always big