Congenital Heart Defects Flashcards Preview

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Flashcards in Congenital Heart Defects Deck (77)
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1
Q
For the fetus the placenta is
A
the oxygenator so the lungs do no work
2
Q
RV & LV contribute equally to
A
the systemic circulation and pump against similar resistance
3
Q
Ductus venosus allows
A
oxygenated blood to bypass the liver
4
Q
Foramen ovale
A
R→L atrial level shunt; shunt that bypasses the lungs, It moves blood from the right atrium of the heart to the left atrium
5
Q
Ductus arteriosus
A
R→L arterial level shunt;

The ductus arteriosus moves blood from the pulmonary artery to the aorta; it allows most of the blood from the right ventricle to bypass the fetus's fluid-filled non-functioning lungs
6
Q
In a right to left shunt, blood __________
A
(that hasn’t traveled to lungs yet) is shunting across to the left side of the heart

-Oxygen and nutrients from the mother's blood are transferred across the placenta to the fetus.
-Goal of fetal circulation is to get oxygenated blood to brain
7
Q
PDA allows blood to go into aorta and into ________
A
vessels of head and neck (getting blood to brain)
8
Q
Normal PaO2 in umbilical vein of fetus
A
30-35 mmHg.
9
Q
Residue 143
A
-Single amino acid change of histidine to serine

-Histidine positively charged; Serine neutral

-This change results in LESS binding of 2,3 BPG to fetal Hb which INCREASES fetal oxygen affinity
*Baby has higher affinity for oxygen from moms blood due to single amino acid change
10
Q
With the first few breaths after baby is born, lungs expand and serve as oxygenator. Placenta is removed from the circuit, systemic pressure _________, pulmonary pressure _________
A
systemic INCREASES
pulmonary DECREASES (so blood can flow to lungs)

-Foramen oval functionally closes
-Ductus arteriosus closes within first 2-3 days
11
Q
After baby is born, pressure is higher
A
in L atrium than R atrium, 1 way valve is closed and flow from R to L stops

-shunts close in first 45 seconds of life
12
Q
Neonates with CHD often rely on _______
A
a patent ductus arteriosus and/or foramen ovale to sustain life

-The ductus normally closes by 3 days
-The foramen ovale normally closes by 3 months
13
Q
What function does the PDA provide after birth in a baby with cyanotic congential heart disease?
A
Provides a source of pulmonary blood flow
14
Q
In the presence of hypoxia or acidosis (present in ductal-dependent lesions), _____________
A
the ductus may remain open for a longer period of time

-As a result, these patients can present to the ED as late as the first 2 weeks of life (Sepsis is usually #1 on differential, congenital heart disease is #2

*Start antibiotics and PGE (to keep PDA open)*
15
Q
S/S of venous congestion
A
Right side: Hepatomegaly, Ascitis, Pleural effusion, Edema

Left side: *Tachypnea, Retractions, Crepitations
Pulmonary edema
16
Q
S/S of lower cardiac output
A
Acutely: Pallor, *Sweating
Cool extremities, increased capillary refill time, Tachycardia

Chronic: *Feeding difficulty, *Fatigue, Poor growth
17
Q
Neonatal EKG findings
A
-Highest peak in limb leads (RVH is NORMAL)
-Normal finding bc R vent was dominant when it was inside mom, takes a while for L vent to bulk up and get bigger
-eventually L vent will have stiffer more muscular will and RV will be more compliant chamber
18
Q
Chromosomal causes of CHD
A
-Down Syndrome: up to 50% will have defects
-VACTERL, CHARGE Association: 50 - 85% will have defects (involve many body systems)
19
Q
Maternal illness that causes CHD
A
-Pre-Gestational Diabetes: 50% increase risk (if diabetes is poorly controlled; vent septal defect, transposition of great arteries, coarctation of aorta)

-Lupus: complete heart block (Abs from mom cross placenta and attack conduction system in baby’s heart; monitor baby heart via EKG)
-Infection (Viral): rubella in 1st 7 wks = Patent Ductus Arteriosus
20
Q
Maternal substance abuse and CHD
A
-Severe FAS (EtOH) = 50% have CHD
21
Q
Down syndrome associations
A
AV canal and VSD
22
Q
Turner syndrome associations
A
Coarctation of aorta
23
Q
Trisomy 13 (Patau syndrome) and 18 (Edwards syndrome)
A
VSD and PDA
24
Q
Fetal alcohol syndrome associations
A
L--> R shunts and metrology of fallot
25
Q
CHARGE syndrome
A
conotruncal lesions (ToF, truncus arteriousus)
26
Q
Pulse ox on arm and leg and difference in more than 10% saturation= ________

(R upper arm sat 100%; Lower extremities O2 sat is LOWER)
A
differential cyanosis

*lower limbs are cyanosed but the upper limbs are not

-will see increased precordial activity and displaced PMI
27
Q
Differential cyanosis is from
A
PDA with R to L shunt or
CoA with PDA after constriction
28
Q
S/S of Pulmonary cyanosis
A
-baby is grunting, struggling to breathe
-tachypnea, distress, retractions with breathing
-cyanosis may improve with crying
-may heart rales, crackles or wheezing in lungs
-normal heart sounds/cardiac silhouette
-CXR shows ground glass, pneumonia, atelectasis, pneumothorax
-normal EKG
-pCO2 increased usually
-PROFOUND response to 100% O2
29
Q
S/S of Cardiac cyanosis
A
-baby is blue, but breathing fine (comfortable)
-cyanosis worsens when baby cries
-hear cardiac murmur
-cardiomegaly/abnormal shape or position of heart
-normal lung fields, may see some decreased vascularity or pulmonary vascular congestion
-EKG shows abnormal rhythm
-pCO2 is normal to low
-NO response to 100% O2
30
Q
Differential pulses, weak in LE, think
A
CoA
31
Q
Bounding pulse, think
A
run-off lesions (L→R PDA shunt, AI, BT shunt)
32
Q
Weak pulse, think
A
Cardiogenic shock or CoA
-Any ductal dependent lesion once the PDA is closing
-baby should have strong femoral pulse
33
Q
If you hear ejection click, think
A
AS or PS
34
Q
If you hear loud S2, think
A
pulmonary HTN
35
Q
If you hear single S2, think
A
one semilunar valve (truncus), anterior aorta (TGA), or pulmonary HTN
36
Q
***Fixed split S2*** think,
A
**ASD**

Case- teenager who used to run track fine, now she is out of breath running around the track once- listen for fixed split S2- problem is ASD
37
Q
Muffled heart sounds and/or a rub, think
A
pericardial effusion ± tamponade
38
Q
Systolic Ejection Murmur =
A
turbulence across a semilunar valve (Ao, Pulm)
39
Q
Holosystolic murmur =
A
turbulence begins with systole (VSD, MR)
40
Q
Continuous murmur =
A
pressure difference in systole and diastole (PDA, BT shunt)
41
Q
Classifying CHD, L --> R shunts indicate
A
Acyanotic HD
42
Q
Classifying CHD, R --> L shunts indicate
A
Cyanotic HD
(baby appears cyanotic due to deoxygenated blood entering the systemic circulation)
43
Q
L-->R "Acyanotic" shunts
A
VSD
PDA
ASD
AV canal (combined ASD/VSD)
(Endocardial cushion defect)

-If there isn’t a big pressure difference, murmurs will be really hard to hear from turbulent flow going through the hole
44
Q
PDA and VSD present in _______
A
-Presents in infancy w/ heart failure, murmur, and poor growth
-Left heart enlargement (LHE)
-Transmits flow and pressure
45
Q
ASD presents in ________
A
-Presents in childhood w/ murmur or exercise intolerance
-Right heart enlargement (RHE)
-Transmits flow only
46
Q
VSD description
A
VSD- higher volume of blood being delivered to babies lungs, every time LV contacts, increased pressure to pulmonary vasculature (bad, normally a low pressure system)
-causes problems sooner (infancy)
47
Q
ASD description
A
ASD- L atrial pressure higher than R, blood coming into R atrium, increased blood flow here too, but NO increased pressure to pulmonary system, just increased volume going to R side of heart
-why these kids present at 12 years
48
Q
Xray findings with CHD
A
-cardiomegaly
-Pulm vasc markings increased in upper and lower zones
-“fluffy”/hazy looking lungs bc increased fluid in lungs
-ASD VSD look similar on xray- both presenting with CHF
49
Q
Is a L to R shunt a cyanotic lesion?
A
No

But it can become one
50
Q
Eisenmenger’s Syndrome
A
A long standing L→R shunt will eventually cause irreversible pulmonary vascular disease
-This occurs sooner in unrepaired VSDs and PDAs (vs an ASD) because of the high pressure transmitted with the VSD/PDA
-Once the PVR (pulm vasc resist) gets very high the shunt reverses (ie- now R→L) and the patient becomes cyanotic

*Critical point- blood switches directions
51
Q
R to L shunts lead to _______
A
cyanotic CHD
-Degree of cyanosis varies depending on the lesion
-Classify based on pulmonary blood flow (PBF)
52
Q
Increased pulmonary blood flow is seen in
A
-Truncus arteriosus
-Total anomalous pulm. venous return (TAPVR)
-Transposition of the great arteries (TGA)


*Presents more often with heart failure (except TGA)
*Pulmonary congestion worsens as neonatal PVR lowers
*Sats can be 93-94% when there is high PBF
(sat is high, baby WON'T look cyanotic)
53
Q
Decreased pulmonary blood flow is seen in
A
-Tetralogy of Fallot
-Tricuspid atresia
-Ebstein’s anomaly

-Presents more often with cyanosis
-See oligemic lung fields
-Closure of PDA may worsen cyanosis

*Will look cyanotic, preventing blood from getting to lungs
-PGE dependent or ductal dependent lesion
54
Q
Truncus arteriosus allows _________
A
TOO MUCH PBF
-mixing before blood gets to aorta
55
Q
Tetralogy of Fallot allows _________
A
TOO LITTLE PBF

-main problem is pulmonary stenosis, VSD is trying to close but increased pressure in R vent doesn’t let that happen, this leads to RVH (working harder to squeeze blood through stenotic pulmonary valve)
56
Q
X-rays of TOF vs Truncus
A
Truncus- Top to bottom looks the same, consistently hazy throughout


TOF- very little pulmonary markings b/c low blood flow to lungs, DARK lung fields
57
Q
Classic CXR finding in TOF is
A
boot shaped heart
-pulmonary vasculature is usually decreased
58
Q
Most common cyanotic congenital heart defect in newborns??
A
-Transposition of the Great Arteries (TGA)
-More males
-Dextroposition
-Parallel circuits
-Incompatible with life unless communication between the two circuits
59
Q
With TGA, mixing most commonly at
A
the atrial level through an ASD or a PFO
-Two levels of mixing are necessary to maintain adequate systemic oxygen delivery with a VSD or PDA serving as an additional site for cardiac mixing.
-In TGA, there can be no fixed shunt in one direction without an equal amount of blood passing in the other direction; otherwise, one circulation would eventually empty into the other.
60
Q
Total Anomalous Pulmonary Venous Return (TAVPR)
A
-a congenital defect of the pulmonary veins
-Nothing filling L atrium pulm veins are emptying somewhere else
-No communication between pulmonary veins and left atrium (LA)
-All four pulmonary veins are malpositioned and make anomalous connections to the systemic venous circulation
61
Q
What must be present in TAVPR for survival?
A
A patent foramen ovale or an atrial septal defect must be present, or else the condition is fatal due to a lack of systemic blood flow
62
Q
4 types of TAVPR
A
1. Supracardiac (50%): blood drains to one of the innominate veins (brachiocephalic veins) or the superior vena cava
2. Cardiac (20%), where blood drains into coronary sinus or directly into right atrium
3. Infradiaphragmatic (20%), where blood drains into portal or hepatic veins
4. Mixed
63
Q
TAVPR blood flow
A
-ASD, so R to L shunt
-Pulmonary venous return flowing away from the heart
64
Q
TAPVR without pulmonary venous obstruction
A
-CHF and growth retardation
-Mild cyanosis
-Precordial bulge with hyperactive RV
-Right ventricular and atrial hypertrophy (RVH – RAH)
-Mod to marked cardiomegaly. **"Snowman” sign**
65
Q
TAPVR with Pulmonary Venous Obstruction
A
Marked cyanosis and respiratory distress in the newborn period
66
Q
Tricuspid Atresia
A
-Absent tricuspid valve and hypoplastic RV
-All have inter-atrial communication
-VSD in 90%, or PDA are necessary
-Right ventricle is hypoplastic
-Severe cyanosis from birth
-Single S2.
-Grade 2-3/6 systolic murmur of VSD
67
Q
Blood flow with tricuspid atresia
A
-LA receives both the entire systemic and pulmonary venous return. (getting blood back from lungs AND, RA is getting blood from SVC and IVC and dumping it into LA)

-The entire mixture flows into the LV, depends on how long LV can pump to BOTH lungs and body
-cyanotic, infant needs PGE
68
Q
Ebstein’s Anomaly
A
-The tricuspid valve is downwardly displaced and adherent to the interventricular septum
-very enlarged R atrium
-Cyanosis and CHF during the first few days of life
-Improvement in oxygenation with reduction of pulmonary vascular resistance
-supraventricular tachycardia (SVT)
69
Q
CXR findings with Ebstein’s Anomaly
A
Cardiomegaly and balloon shaped heart
70
Q
Case: Baby is a 4 day old infant that is brought in by parent to the ER you are working. Mom states
‘baby was born last week and went home after 2 days in the hospital’........‘Baby has been breathing fast and is not eating well’

First on differential?
A
#1 Sepsis
#2 Congenital Heart Disease (CHD)
71
Q
What does giving a CHD baby PGE do?
A
re-opens the PDA

(Without a PDA there is no blood flow to the abdomen and lower extremities; blue blood is better than no blood)
72
Q
Hypoplastic Left Heart Syndrome
A
-baby will start showing s/s about 2 days after it goes home when PDA closes (need to give baby PGE to reopen it)
-atrial septal defect (opening)
-small hypoplastic aorta
-VERY small left ventricle (hypoplastic)
73
Q
What to give a baby presenting 2-10 days after birth in shock
A
PGE should be started in addition to antibiotics
74
Q
During HLHS or CRITICAL PS/AS/CoA, there is a ductal-dependent lesion

One ventricle pumps both PBF & SBF; Difficult to balance PBF & SBF

How to help this?
A
-Too much blood to lungs, not enough to body (hypotension); increased pulm vasc resistance, increased CO2 on ventilator, vasoconstrics pulm vessels or decrease O2 which does the same thing
-Less blood to lungs, push more to system, make his body less acidotic
75
Q
Norwood Procedure
A
(Step 1) 1st procedure done- combine pulm artery and what was ascending aorta, make brand new aorta, get pulm blood flow from BT shunt

YES- THERE WILL BE MURMUR (BT shunt is very small, lots of turbulence)

-What is the purpose of the Blalock-Taussig shunt? Pulmonary blood flow (since they cut off pulm artery)
76
Q
Bidirectional Glenn Procedure
A
Step 2- they come back at 4-5 months old, take down BT shunt, connect SVC directly to pulmonary artery, SVC is source of pulm blood flow
(can't do this right away bc pulmonary pressures are too high and systemic p is too low)

-What is the purpose of the Glenn? SVC hook up

-Is there a murmur? NO (large vessel, BT shunt was very small causing turbulent blood flow)
77
Q
Fontan circuit procedure
A
Last stage- Only have 1 ventricle pumping, create small valve (hole) to relieve pressure, somewhere else for blood to go

-All blood goes right to pulm artery instead of back to heart