2: Cardio - Cyanotic Heart Defects Flashcards

1
Q

What is cyanotic congenital heart disease

A

Congenital HD characterised by right-to-left shunt. Meaning deoxygenated blood enters oxygenated systemic. Hypoxaemia results as cyanosis

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2
Q

What are the 5 T’s of cyanotic HD

A
TOF
TGA
Tricuspid atresia
Total anomalous pulmonary venous return 
Truncus arteriosus
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3
Q

What is tetralogy of fallot

A

Combination of four heart conditions

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4
Q

What is a way to remember 4 abnormalities in TOF

A

VORP

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5
Q

What are the four abnormalities in TOF

A

VSD
Over-riding aorta
Right ventricular hypertrophy
Pulmonary artery stenosis

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6
Q

What is the most common cyanotic congenital heart condition

A

TOF

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7
Q

What condition is TOF associated with

A

DiGeorge’s Syndrome

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8
Q

What is DiGeorge’s Syndrome

A

22q 11.2 deletion syndrome

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9
Q

How is TOF typically diagnosed

A

Antenatally

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10
Q

If not identified antenatally what age does TOF tend to present

A

1-2 months. Can be picked up to 6m afterwards

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11
Q

What are three clinical features of TOF

A
  1. Ejection systolic murmur
  2. Tet spells
  3. Squatting
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12
Q

What are tet spells

A

Intermittent, unpredictable episodes of tachypnoea, restlessness and cyanosis that lasts minutes-to-hours. Associated with physical stress.

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13
Q

Why do children with TOF squat

A

Squatting increases peripheral vascular resistance. This increases pressure in left-side of the heart reducing right-to-left shunt and subsequent hyperaemia.

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14
Q

What are three possible triggers for Tet spells

A
  • Defecation
  • Feeding
  • Crying
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15
Q

What murmur is heard in TOF

A

Harsh ejection systolic murmur

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16
Q

Where is murmur in TOF loudest

A

Erb’s point or left-upper sternal edge

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17
Q

Where is Erb’s point

A

3rd IC space. Left lower sternal edge.

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18
Q

What causes the murmur in TOF

A

Pulmonary stenosis

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19
Q

What are two other signs of TOF

A
  • Right ventricular heave

- Cyanosed w/clubbing

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20
Q

What is TOF caused by

A

Anterior misalignment of the aorticopulmonary septum

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21
Q

Explain why there is RVH in TOF

A

Pulmonary stenosis reduces outflow of blood. To try and maintain output right ventricle undergoes hypertrophy to increase pressure.

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22
Q

Why is there a right-to-left shunt in TOF

A

Pulmonary stenosis causes RVH. This increases pressure in the right-side so it is greater than the left. VSD creates a tract between right and left sides of the heart. This means blood can pass.

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23
Q

What determines degree of cyanosis in TOF and why

A

Degree of pulmonary stenosis - as this determines extent of RVH and hence pressure in right ventricle.

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24
Q

At what SpO2 will a child develop cyanosis

A

<80%

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25
Q

What are three investigations in TOF

A

SpO2
CXR
ECG

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26
Q

What will be seen on CXR in TOF

A

Boot-shaped heart: due to RVH

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27
Q

What will be seen on ECG

A

RVH

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28
Q

What 4 things are done to manage cyanotic attacks (Tet spells) in TOF

A
  1. Oxygen
  2. Knee’s up position
  3. B-blockers
  4. IV morphine
29
Q

Why are B-blockers given in TOF attacks

A

Reduce spasm of infundibulum (pulmonary stenosis)

30
Q

How is severe TOF managed in the neonatal period

A
  • IV prostaglandin E

- Blalock-Taussig Shunt

31
Q

What is a blalock-taussig shunt and what is its purpose

A

Blalock Taussig shunt connects aorta to pulmonary.a. This means deoxygenated blood that has been ejected into the aorta can pass back to pulmonary.a to be oxygenated by the lungs

32
Q

What is the definitive management of TOF

A

Surgical correction - resection infundibulum to reverse PA stenosis and VSD correction

33
Q

When can surgery for TOF be performed

A

> 4 months

34
Q

What can chronic cyanosis lead to in TOF

A

polycythaemia

35
Q

What are 4 complications of TOF

A
  • Cerebral thrombosis + ischaemia
  • Brain abscess
  • Bacterial endocarditis
  • Congestive HF
36
Q

What is transposition of the great arteries

A

Anatomical reversal of pulmonary artery and aorta

37
Q

What are 5 maternal risk factors for TGA

A
  • Diabetes
  • > 40
  • Congenital rubella
  • Malnutrition
  • Alcohol
38
Q

What is another risk factor for TGA

A

Genetic syndromes: Trisomies, DiGeorge

39
Q

If there is no mixing of oxygenated and deoxygenated blood how will TGA present

A

Death

40
Q

How does TGA typically present clinically

A

Post-natal cyanosis. Typically presents with cyanosis once the ductus arteriosus closes. Neonates will be breathless and have poor feeding

41
Q

What is a sign of TGA on auscultation

A

Single loud S2

42
Q

Explain the pathophysiology of TGA

A

In TGA anatomical roles aorta and PA are reversed.

On right side, deoxygenated blood enters right atrium, passes to right ventricle and is then ejected via aorta. Meaning deoxygenated blood passes to systemic circulation.

On left side blood enters via pulmonary vein to left atrium passes to left ventricle and is ejected via pulmonary artery.

43
Q

Explain why babies survive in-utero with TGA

A

As oxygen is obtained from ductus venosus (from placenta) which enters IVC

44
Q

Why are neonates with TGA symptomatic

A

As need to rely on lungs to obtain oxygen, no longer receiving oxygen via the placenta. If no mixing of circuits infant will die. If patent FO, VSD or patent DA enables mixing - will survive.

45
Q

Why does TGA lead to heart failure

A

As right-side of the heart has less musculature and has not been designed to maintain systemic circulation

46
Q

What is levo-TGA

A

Where ventricles and AV valves switch - not vessels meaning circulation is functional. Children asymptomatic until later life present with RVH and tricuspid regurgitation.

47
Q

What investigations are ordered in TGA

A

CXR

ECHO

48
Q

What will be seen on x-ray in TGA and why

A

Egg on string appearance.

Large cardio-mediastinal silhouette causes globular appearance of the heart. Stress causes thymic atrophy which appears as the string.

49
Q

What is first-line management of TGA in short term and why

A

IV PGEI infusion. PGs maintain patency of ductus arteriosus enabling mixing

50
Q

What is definitive management of TGA

A

Surgical correction by Arterial switch procedure.

51
Q

When is arterial switch procedure performed

A

First 2W

52
Q

What is the arterial switch procedure

A

Switching of aorta and PA. With associated coronary vessels

53
Q

When is ballon arterial septostomy indicated and what does it involve

A

If unsuitable for surgery. Involves creating a large ASD to enable mixing

54
Q

What is mortality rate of TGA without surgery

A

90%

55
Q

What is tricuspid atresia

A

Absent or rudimentary tricuspid valve

56
Q

How will tricuspid atresia present clinically

A

Cyanosis days following birth

57
Q

Explain pathophysiology of tricuspid atresia

A

Tricuspid atresia means there is no connection between right atrium and right ventricle. Venous blood is diverted from right atrium to left side via patent foramen ovale. Oxygenation depends on PDA.

58
Q

How will tricuspid atresia present on ECG and why

A
  • Left axis deviation = due to left ventricular hypertrophy

- P mitrale

59
Q

How will tricuspid atresia present on CXR and why

A

Decreased pulmonary markings - due to decreased blood flow to the lungs

60
Q

What 3 investigations are ordered for tricuspid atresia

A
  • ECG
  • CXR
  • ECHO
61
Q

What is given in short-term to manage tricuspid atresia

A

IV PGEI - to maintain patency of ductus arteriosus and oxygenation

62
Q

What is ‘long-term’ management of tricuspid atresia

A

Surgical correction

63
Q

What surgical correction of tricuspid atresia is offered in neonatal period

A
  • Blalock trussing shunt

- or pulmonary artery banding

64
Q

What is a blalock tausig shunt

A

Connection between pulmonary. a and aorta. This enables deoxygenated blood pumped out by aorta to return to pulmonary artery down a pressure gradient and undergo oxygenation

65
Q

At 6 months of age what surgical procedure is offered for tricuspid atresia

A

Glenn shunt

66
Q

What is a Glenn shunt

A

Shunt placed between aorta and pulmonary artery

67
Q

What is offered to pre-school children with tricuspid atresia

A

Fontan procedure

68
Q

What is a Fontan procedure

A

IVC is connect to pulmonary artery so blood may be oxygenated directly