Congenital Heart Disease 2 Flashcards

1
Q

What is a VSD?

A

Ventricular septal defect.

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2
Q

What % of all congenital heart defects is VSD?

A

20%

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3
Q

How many fetuses have VSDs?

A

About 5%. Although there is a high incidence of spontaneous closure

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4
Q

True or False: VSDs are often seen in combination with other complex congenital heart lesions

A

True

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5
Q

When does Ventricular septation occur?

A

Post loop stage (day 28-42)

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6
Q

How many endocardial cushions form to make the ventricular septum?

A

4 (superior, inferior, right, and left)

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7
Q

Which 2 endocardial cushions fuse to create the left atrioventricular canal and right atrioventricular canal?

A

Superior and inferior endocardial cushions.

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8
Q

What is the membranous septum; interventricular portion?

A

The membranous portion of the interventricular septum is the most common area of VSD development. This is called a perimembranous VSD

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9
Q

What is the most common type of VSD?

A

Perimembranous VSD. deficiency or lack of the membranous portion of the interventricular septum.

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10
Q

What does the superior endocardial cushion turn into?

A
  • The left surface of the outlet portion of the interventricular septum.
  • Part of the mitral valve
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11
Q

What does the inferior endocardial cushion turn into?

A
  • The inlet portion of the interventricular septum
  • Membranous portion of the interventricular septum
  • Parts of the tricuspid and mitral valves
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12
Q

What does the right endocardial cushion turn into?

A

Parts of the tricuspid valve

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13
Q

What does the left endocardial cushion turn into?

A

Posterior leaflet of the mitral valve.

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14
Q

Of the 4 endocardial cushions, which one is the perimembranous VSD a defect in?

A

Inferior Endocardial Cushion

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15
Q

What % of all VSDs is the perimembranous VSD?

A

70%

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16
Q

What is a muscular VSD?

A

10% of all VSDs. They form in any part of the muscular part of the septum (in contrast the membranous part).

Muscular VSDs are rarely and issue and often close on their own while perimembranous often do not.

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17
Q

What is considered a large defect for VSDs?

A

When the defect diameter is the same as or greater than the aortic orifice.

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18
Q

Explain the shunt direction and magnitude of VSD and ASD

A

For ASD, the blood in the LA is deciding whether to go through the ASD to the RA or to the LV. So, the compliance of the ventricles makes the difference.

For VSD, the blood in the LV is deciding whether to go through the VSD or through the aorta. So, the difference between systemic and pulmonary vascular resistances makes the difference.

These are still both left-to-right shunts (typically) because left is greater pressure than right.

Also, keep in mind that obstructive lesions (e.g. pulmonary or aortic valve stenosis) will also influence shunt magnitude and direction

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19
Q

In VSD, end-diastolic volume is increased in which chamber of the heart?

A

LV.

WTF? shouldn’t a ventricular septum hole make it so blood leaks out of the LV for less end-diastolic volume? No. Normally, all of the blood in the LV leaves through the aorta. But in VS, some of the blood that’s supposed to leave goes through the VSD to the RV and through the lungs back to the LV. The LV gets increased end-diastolic volume. The increased end-diastolic volume increases the muscle fiber length in the LV which increases contractility which results in an increased LV output. (This does not mean increased CO output… because the LV contractility is increased and LV output is increased but some of that “output” is back into the RV)

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20
Q

What are VSD symptoms after birth?

A

Typically asymptomatic until PVR starts to fall, even if the defect is large (takes a few days to fall). The fall in PVR is delayed at elevated altitudes.

In large VSDs

  • there can be respiratory distress and diaphoresis, especially when feeding
  • failure to thrive

In small VSDs
Tachypnea and diaphoresis are usually mild or absent.

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21
Q

What are the physical exam findings for a large VSD?

A

Active precordium
Accentuated second heart sound (from pulmonary HTN)
2-3/6 harsh, holosystolic murmur loudest at LLSB, but can usually be heard throughout the chest
Diastolic murmur secondary to increased flow across the mitral valve.

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22
Q

What are the physical exam findings for small VSDs?

A

Precordial activity is usually normal
Normal second heart sound
2-4/6 early systolic murmur
No diastolic murmur

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23
Q

What does the murmur volume mean?

A

A smaller VSD or a VSD starting to close will have a louder sound. Louder is often a good sign in VSDs.

Louder murmur could also mean a lower pulmonary vascular resistance. (which is also a good thing bc you aren’t having pulmonary HTN which happens in larger VSDs)

A murmur that goes away is not always a good thing. It may mean that the VSD has closed but it can also mean that the VSD is large with equalization of RV and LV pressure and elevation in pulmonary vascular resistance (pulmonary HTN)

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24
Q

What is the diagnostic tool of choice for VSDs?

A

Echo (gold standard)
Defines location and number of defects
Can estimate magnitude of shunt
Can identify associated lesions or complicating factors such as aortic insufficiency

– additional –

ECG
Normal in small defects
Right axis deviation and increase in RV and LV voltages (combined hypertrophy)

Radiograph
Increased lung vascularity. Enlarged main pulmonary artery. Cardiomegaly.

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25
Q

What is non-surgical management of VSD?

A

Symptom based management in infancy.
Diuretics can prevent pulmonary edema. Digoxin and afterload reduction can help (ACE inhibitors)
Small defects are just observed and hopefully they close on their own.

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26
Q

What are indications for surgical closure of a VSD? (3)

A
  1. Development of pulmonary vascular changes in the setting of a large defect.
  2. Persistent symptoms of poor growth despite medical therapy.
  3. Development of secondary complications (aortic insufficiency, double-chambered RV, etc)
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27
Q

True or false: Large VSDs can increase in size over time.

A

False. Many large defects actually decrease in size. However, large defects need to be treated because if they are left untreated it can be devastating.

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28
Q

What is Eisenmenger’s Syndrome?

A

Eisenmenger’s syndrome happens in large left to right shunts (more common in VSD but can happen in ASD).

A large left to right shunt causes an increase of pulmonary blood flow which results in a muscularization of pulmonary arterioles creating pulmonary HTN and increased right ventricular pressure. As this progresses, there can be a shunt reversal and now the blood is going from right to left. The blood going from RV to LV is deoxygenated and results in cyanosis and clubbing.

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29
Q

How do you fix eisenmenger’s syndrome?

A

It’s irreversible. You can’t close the VSD because these patients are relying on that hole to get blood out of the RV since the pulmonary HTN is so high.

This results in death or can maybe be helped by a heart/lung transplant.

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30
Q

What is Tetralogy of Fallot?

A

ToF is a cyanotic heart disease complex

  1. RV outflow tract obstruction
  2. RV hypertrophy
  3. Extraposition of the aorta (aorta overrides the VSD)
  4. VSD
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31
Q

Of all congenital heart defects, what % is ToF?

A

15%

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32
Q

What is the most common cyanotic congenital heart disease?

A

ToF

33
Q

The Tetralogy of Fallot is actually based on one abnormal embryological basis. What is it?

A

Abnormal development of the clonal crests resulting in an infundibular (outlet) septum that is displaced anteriorly , rightward, and superiorly. This results in the obstruction of the sub pulmonary outflow tract.

34
Q

In ToF where is the aorta sitting?

A

It sits right above the VSD

35
Q

What are the RV and LV pressures like in ToF

A

The RV and LV pressures are equal. The VSD is large and the aorta is sitting right above the VSD.

36
Q

In TOF, the magnitude of pulmonary blood flow is the main concern for these patients. What are the 4 factors that influence this?

A
  1. Source of pulmonary flow
  2. Severity of RV outflow obstruction
  3. Balance of RV and LV pressure
  4. Presence of Ductus arteriosis
37
Q

In TOF, what if the outflow obstruction of the RV is severe?

A

You need to make sure the ductus arteriosis stays open because it will serve as the main pulmonary blood flow tract. These patients need to be put on prostaglandins.

38
Q

What causes the RV outflow obstruction in TOF?

A

The narrowing of the infundibular region causes RV outflow obstruction. There can also be stenosis of the pulmonary valve which makes it worse.

39
Q

What is the shunt direction for TOF?

A

It depends on the relative resistance of flow.

Right to Left shunt:
If RV outflow resistance is higher than systemic vascular resistance then you get a R to L shunt which results in cyanosis (blue tetralogy)

Left to Right Shunt
If Rv outflow resistance is lower than systemic vascular resistance, then you get a L to R shunt which results in “pink tetralogy” (no cyanosis)

40
Q

What are “Tet Spells”?

A

Hypoxic or hyper cyanotic spells which can be life threatening. These typically occur at 2-6 months of age and the mechanism is still unclear.

Speculated mechanism is that infundibular spasm causes decreased pulmonary blood flow. Spasms prevent any blood from going into pulmonary artery.

41
Q

Tet spells can precipitate spontaneously, but what are 3 things that can also start tet spells?

A
  1. Prolonged crying
  2. Anemia
  3. Dehydration
42
Q

What are 4 exam findings for Tet Spells?

A
  1. Blue! (cyanotic)
  2. Decreased intensity of murmur. The murmurs from TOF is from the blood flow going through the obstructed outflow tract of the RV. But, during tet spells, there isn’t any blood going to the pulmonary artery so the murmur decreases.
  3. Altered consciousness
  4. Seizures.
43
Q

How do you treat Tet Spells? (4 things)

A

Increase pulmonary blood flow.

  1. Knee to chest position increases systemic vascular resistance which forces blood to go through the pulmonary artery instead. (shifts blood shunt direction)
  2. Phenylephrine (0.02mg/kg IV) also increases systemic vascular resistance
  3. Morphine for sedative effect (to stop spasm)
  4. Volume expansion with IV fluids (to try to get more volume into that right heart)
44
Q

What is a theoretical prevention for Tet Spells?

A

Beta blockers. Still just a theory

45
Q

When are kids with TOF repaired?

A

Try to repair at 2-4 months before tet spell risk increases

46
Q

How do patients with TOF present?

A

They almost always present in infancy with blue baby with loud murmur. It’s typically a loud, palpable murmur (thrill).

Cyanosis can worsen as ductus arteriosis closes. Some with severe RVOT obstruction may have ductal dependent PBF and need prostaglandins to keep the ductus open until surgical repair.

47
Q

Patients with TOF can present variably depending on 3 factors. What are these factors?

A

Size of VSD
Severity of RV outflow obstruction
Systemic vascular resistance

48
Q

A baby presents with a loud, palpable murmur that and is blue. What is this baby likely to have?

A

TOF

49
Q

How does Blue Tet present?

A

Tachycardic and cyanotic

50
Q

How does Pink Tet present?

A

Diaphoretic and tachypnic (like large VSD symptoms)

51
Q

What is a physical exam finding that can be present in TOF due to RV hypertrophy?

A

Precordial heave/impulse at LLSB

52
Q

What murmur is present in TOF?

A

2-3/6 short systolic murmur from pulmonary stenosis/outflow tract block

53
Q

What is the ECG finding for TOF?

A

Right axis deviation and RV hypertrophy

54
Q

How do you manage TOF patients?

A

Outpatient medical management is possible for infants that have adequate O2 sat once the ductus arteriosis has closed. Beta blocker (propranolol) may be used for tet spell prevention (theoretically). Elective surgical repair at 2-4 months before tet spell risk increases.

If a patient is dependent on the ductus arteriosus for pulmonary blood flow, you want to maintain the duct by giving prostaglandins and do an early surgical repair or palliation.

55
Q

How do you surgically repair TOF?

A
  1. Close VSD with patch

2. Clear out RV outflow tract. Often needs work to make the opening bigger and application of patch.

56
Q

TOF often causes problems with a particular valve. Which valve?

A

Pulmonary valve. The obstruction in this area causes problems with developing the valve and it can get leaky as time goes on. These patients ultimately need repair of the valve usually in their 2nd decade of life.

57
Q

What is the natural history of TOF?

A

If the RVOT obstruction is severe and patient has ductal dependent PBF, there is death at the time of ductal closure unless there is intervention.

Otherwise, patients with TOF can survive into young adulthood with the following symptoms:

  1. Cyanotic (75-90% sat)
  2. Clubbing of fingers
  3. Poorly developed dental enamel, soft teeth
  4. Bleeding tendencies
  5. Limited exercise tolerance (squatting with exercise attempting to increase SVR and improve PBF)
  6. Arrhythmias
58
Q

A child is known to squat during play to catch their breath. What is this a sign of?

A

TOF. This is the child’s attempt at increasing systemic vascular resistance which will increase the left-to-right flow of the VSD in TOF which causes more blood to go through the obstructed outflow tract in the RV to go through the lungs. This results in having higher O2 sat and the child can continue playing until they feel winded again.

These kids are often from other countries as children born in the U.S. typically are diagnosed with TOF early in their lives.

59
Q

What are cerebral abscesses?

A

It’s a known complication of unprepared cyanotic congenital heart disease (not only TOF).

  • Unusual before age of 1.5-2 years
  • Persistent unexplained fevers
  • Behavioral chances
60
Q

Why do cerebral abscesses occur in TOF?

A

Typically in a normal patient, bacteria that’s stirred up in the venous system goes to the lungs where they are filtered. However, in TOF, there is the right-to-left shunting that can occur when the RV outflow tract is obstructed and the bacteria can travel out the aorta and to the brain.

61
Q

Why do we need to be extra careful in when giving anything IV to TOF (or any other patient with possible right to left shunt)?

A

Typically, when you give something IV, there are micro bubbles which are injected and they aren’t harmful because they get to the lungs and are filtered out. However, in patients with possible right to left shunt, like in TOF, air bubbles can bypass the lungs and get to the brain to cause damage.

62
Q

What is coarctation of the aorta?

A

Narrowing of aortic lumen

63
Q

Of all the congenital heart lesions, what % is coarctation of aorta?

A

5-8%

64
Q

What are 3 theories for the embryological basis of coarctation of the aorta?

A
  1. Extension of ductal tissue into the aortic arch. (this ductal tissue closes after birth and the thought is that if there is extra ductal tissue inside the aortic arch, this begins to close and make the aortic lumen smaller)
  2. Disturbance of subclavian artery migration
  3. Altered blood flow in the fetus causes decreased blood flow through the isthmus resulting in poor development of this area.
65
Q

Patient’s with Turner’s Syndrome have a greater prevalence of what congenital heart defect?

A

Coarctation of the aorta

66
Q

In coarctation of the aorta, which part of the aorta is usually the site of coarctation?

A

The isthmus. This is the area distal to the left subclavian artery. Often at the level of ductus arteriosis formation across from the ductus (juxtaductal).

Can rarely occur in descending or abdominal aorta.

67
Q

Which parts of the aorta can dilate due to the coarctation of the aorta?

A

The isthmus and descending aorta can dilate on either side of the coarctation

68
Q

Why are babies born with coarctation of the aorta put on prostaglandins?

A

It is thought that the coarctation can be due to some of the extra ductal tissue on the aortic arch. Giving prostaglandins to these babies will keep the aorta open and prevent the possibility of closing. This is done until surgical intervention.

69
Q

What BP findings can be used to detect coarctation of the aorta?

A

Typically, the coarctation is after the left subclavian arteries. So, there is a pressure drop at the point of coarctation so the patient will have higher BP in their arms than their legs.

70
Q

A baby is found with high blood pressure taken at the brachial artery. What do you think?

A

It’s absolutely not normal for babies to have any sort of HTN. High blood pressure measured at the arm should give you reason to suspect coarctation of the aorta. Check the BP at the leg to see if it’s lower. If it’s lower, it’s coarctation because of the pressure drop after the level of the left subclavian artery. If the BP is high, you’re concerned about kidney problems.

71
Q

What are clinical presentations of coarctation of aorta?

A

Can be asymptomatic as newborn because occlusion isn’t that bad or there is help from ductus arteriosis. However, they become symptomatic after ductus closes. (tachypnea, diaphoresis, poor feeding, and shock with cardiac failure)

Symptoms from poor descending aorta perfusions.

  • Decreased blood flow to the bowel (if severe, can result with necrotizing enterocolitis which is life threatening)
  • Decreased blood flow to leg muscles. Older children complain of leg pain with exercise
  • Decreased blood flow to the kidneys. This causes increased renin-angiotensin system activation and rebound HTN after repair of coarctation.

Adults with coarctation can present with systemic HTN.

72
Q

What physical exam findings help you diagnose coarctation of the aorta?

A
  1. Tachycardic
  2. Blood pressure difference between upper and lower extremities
  3. Pulmonary rales and/or hepatomegaly (heart failure symptoms)
  4. Accentuated S2 and S3 gallop may be heard
  5. Soft systolic murmur is possible
  6. Systolic click over apex if bicuspid aortic valve is associated (difficult to appreciate in infants)
73
Q

What are chest x-ray findings that show coarctation of the aorta? (2 things)

A
  1. Rib notching. This is from dilated intercostal arteries. This happens because the BP before the coarctation is higher and causes dilated intercostal arteries.
  2. 3 sign. The top part of the 3 is the aortic knob, the middle of the 3 is the coarctation, the bottom of the 3 is post-stenotic dilation.
74
Q

What imaging do you use to confirm coarctation of aorta?

A

Echocardiography.

  • Site and severity
  • Head and neck vessel anatomy
  • Presence of ductus
  • Identification of associated intracardiac anomalies (bicuspid aortic valve in about 50% of these patients, VSD, or aortic or sub aortic stenosis)
75
Q

How do you manage coarctation of aorta? (infants, young children, and adolescents/adults)

A

Infants:
Maintain on prostaglandins until surgery
End-to-end anastomosis surgical repair
Risk of recoarctation and aneurysm long term.

Young children:
Blood angioplasty or surgery

Adolescents/Adults:
Surgery vs stent placement

76
Q

What is the surgical procedure for fixing coarctation in infants?

A

You cut out the whole isthmus and ductus because you don’t want to leave any ductal tissue behind. Then you reconnect the aortic arch to the descending aorta.

77
Q

Why don’t you want to use stent in fixing coarctation in infants?

A

The stents are too small and wouldn’t grow with the patient properly

78
Q

What is the natural history for coarctation of aorta?

A

Development of collateral arteries to supply blood flow to tissue/organs below the obstruction

The BP differential between upper and lower extremities is variable.