Congenital Heart Disease 1, 2, 3

Question 1

structural anomalies of the heart present though not necessarily manifest at birth

Answer 1

congenital heart disease

Question 2

How does pulmonary edema due to CHD differ from pulmonary edema in adults?

Answer 2

interstitial vs alveolar

Question 3

How does CHD contribute to pneumonia risk in infants?

Answer 3

increased pulmonary flow manifests as dilation of pulmonary arteries –> bronchiolar compression –> poor movement in bronchioles –> infection

Question 4

What constitutes pulmonary vascular disease due to CHD?

Answer 4

high pressure in pulmonary arteries leads to scarring AKA Eisenmenger reaction–> rate of development is dependent on pressure and o2 sat

Question 5

How does ventricular failure manifest in CHD?

Answer 5

exercise/feeding intolerance, growth failure, elevation of venous pressures (pulmonary edema, hepatomegaly)

Question 6

What are the consequences of cyanosis?

Answer 6

low o2/rbc –> metabolic acidosis

• can compensate by polycythemia but this can lead to hyperviscosity (too many RBCs) which has risk of clotting and exercise intolerance
• if can’t compensate due to iron-def anemia –> can have the clinical issues without looking cyanotic

Question 7

T/F high pulmonary blood flow can accelerate pulmonary vascular disease

Answer 7

T –> especially if cyanotic

Question 8

2 categories of acyanotic CHD

Answer 8

left to right shunts, obstructive disease

Question 9

How does resistance factor into the determination of flow through a large VSD?

Answer 9

pulmonary flow depends on the ratio of pulmonary to systemic resistance

*the pressures are the same with a big VSD so pressure difference absolutely cannot determine the flow

Question 10

Normally, pulmonary vascular resistance rises/falls over the first week of life

Answer 10

falls –> smooth muscle in lungs has to relax to allow blood flow

Question 11

W/a large VSD, what happens to pulmonary vascular resistance over the first weeks of life?

Answer 11

falls slowly for several weeks then rises up (as smooth muscle hypertrophy, scarring increases a la eisenmenger, resistance increases again)

Question 12

W/a large ASD, what happens to pulmonary vascular resistance over the first weeks of life?

Answer 12

nothing –> blood in atrium doesnt affect what happens in lungs –> AV and semilunar valves are never open simultaneously

Question 13

Why is flow normal early in a VSD?

Answer 13

both resistance and pressure is high –> despite big hole, blood doesn’t want to flow L to R b/c of high resistance –> flow through the hole is minimal (no murmur in 1st week of life)

Question 14

What happens to flow later in a VSD?

Answer 14

to compensate for VSD, pulmonary arteries dilate and blood volume increases –> by the time resistance is reduced in lungs, flow increases to compensate for high pressure

hi pressure = hi flow * nl resistance

Question 15

As the eisenmenger reaction sets in due to VSD what happens to the heart?

Answer 15

after initial compensation, lung scarring occurs –> increase lung resistance –> flow decrease –> volume handling is reduced to normal and heart starts shrinking–> pulmonary resistance exceeds systemic resistance and shunt reversal occurs –> deox blood mixes with ox blood on systemic side –> cyanosis

Question 16

Why are there multiple murmurs in a large VSD?

Answer 16

1. holosystolic murmur through VSD
2. middiastolic murmur (sounds like mitral stenosis) through mitral valve b/c of large volume of pulmonary return passing from atrium to ventricle

Question 17

Signs of Eisenmenger complex

Answer 17

murmur goes away –> rely on a loud single second heart sound + right ventricular hypertrophy on EKG

Question 18

EKG findings in the course of acyanotic CHD

Answer 18

initially normal –> after drop in pulmonary resistance, left sided hypertrophy –> as pulmonary resistance increases, biventricular hypertrophy (heart shrinks generally as volume reduces) –> right ventricular hypertrophy

Question 19

Which way does flow go across ASD? newborn

Answer 19

no flow –> right ventricle and left ventricle have similar compliance as they have shared load in utero

Question 20

Which way does flow go across ASD? toddler

Answer 20

RV compliance increases b/c it is thinner –> flow goes from left to right in atria –> RV has to handle extra work hence hypertrophy/RA dilates –> flow across pulmonary valve = murmur (sounds like pulmonary stenosis)

Question 21

Difference between VSD and PDA shunting?

Answer 21

VSD can only shunt when valves are open whereas PDA shunting occurs all the time as there is no valve –> even a small PDA can have a lot of flow

*continuous murmur –> systolic murmur that continues past S2

Question 22

How can fetal coarctation lead to hypertension?

Answer 22

aortic obstruction like a bicuspid valve reduces flow in aorta towards brain –> retrograde flow up aorta from ductus arteriosus compensates by splitting –> shelf creates at the split point –> when ductus closes, the shelf point remains and creates a discrete coarctation/narrowing of aortic lumen –> collaterals form to ensure blood flow however kidneys lose pulsatile flow and pump out renin leading to upper extremity hypertension

Question 23

What is a fetal hypoplastic arch?

Answer 23

if instead of late-presenting (i.e. in late fetal life) aortic obstruction occurs, can cope. however, if have a VSD (or other structural defect) that forms before the formation of the aortic arch, the aortic arch will not develop to its full width –> loss of lower extremity flow after closure of DA –> shock in early infancy

Question 24

Disease manifestations of left heart obstructive lesions

Answer 24

1. left atrial htn
2. ventricular hypertrophy
3. ductal dependence (shock when ductus closed)

Question 25

Complications of left heart obstructive lesions

Answer 25

CHF, acidosis, circulatory collapse, sudden death, endocarditis

Question 26

What are the two types of cyanotic CHD?

Answer 26

1. PBF dependent (cyanosis depends on PBF) - tetralogy of fallot
2. PBF independent -transposition

Question 27

How does pulmonary blood flow determine cyanosis in cyanotic CHD?

Answer 27

PBF proportional to systemic resistance/pulmonary resistance –> as PBF increases, cyanosis decreases

*usually have decreased PBF –> unlimited systemic-pulmonic mixing leads to cyanosis

Question 28

Tetralogy of Fallot

Answer 28

1. VSD
2. narrowed pulmonary outflow tract + conal septal shift
3. RVH (due to VSD not /bc of the pulmonary stenosis)
4. overriding aorta

Question 29

Transposition of the great arteries

Answer 29

2 separate circulations: aorta comes off RV and PA comes off LV –> PFO permits limited mixing –> cyanosis not proportional to PBF (in fact have increased PBF)

Question 30

What determines mixing with an ASD (as in when trying to repair a transposition)

Answer 30

1. size of ASD
2. ventricular compliance (as PR falls, left ventricular compliance improves –> when blood comes back to the atria, it will store in LV until pulmonary valve is closed at which point the right side of the heart will get a boost of blood)

Question 31

Complications of cyanotic CHD

Answer 31

1. polycythemia
2. stroke
3. brain abscess
4. growth failure
5. bilirubin gall stones