[16] Tetralogy of Fallot

Question 1

What is Tetralogy of Fallot?

Answer 1

A congenital cardiac malformation involving anterior and cephalad deviation of the muscular outlet of the ventricular septum resulting in 4 classical findings

Question 2

What are the 4 classical findings of Tetralogy of Fallot?

Answer 2

• Large VSD
• Overriding aorta
• Sub-pulmonary stenosis
• Right ventricular hypertrophy

Question 3

What kind of congenital heart disease is T of F?

Answer 3

Cyanotic

Question 4

Why is T of F a cyanotic heart defect?

Answer 4

There is right to left shunting via the VSD due to the pulmonary stenosis and right sided hypertrophy

Question 5

What are the risk factors for T of F?

Answer 5

• Trisomy 21, 18, or 13
• DiGeorge syndrome
• Alagille’s syndrome
• Mutation in NKX2.5 gene

Question 6

When are most children with T of F diagnosed?

Answer 6

Antenatally or following identification of a murmur in the first 2 months

Question 7

What are the clinical features of T of F?

Answer 7

• Hypercyanotic episodes
• Harsh systolic ejection murmur
• Cyanosis
• Tachypnoea
• Clubbing of fingers and toes in older children

Question 8

What is a hypercyanotic episode?

Answer 8

Rapid increase in cyanosis with irritability or crying and breathlessness and pallor

Question 9

When is the harsh systolic ejection murmur first heard?

Answer 9

From the first day of life

Question 10

What will happen as right ventricular outflow obstruction increases?

Answer 10

The murmur will shorten and cyanosis will increase

Question 11

What investigations can be used in T of F?

Answer 11

• CXR
• ECG
• Echo
• Cardiac cathaterisation

Question 12

What will a CXR show in T of F?

Answer 12

• Relatively small heart
• Uptilted apex (boot shaped) due to right ventricular hypertrophy
• Right-sided aortic arch
• Pulmonary artery ‘bay’
• Decreased pulmonary vascular markings

Question 13

What will an echo show in T of F?

Answer 13

Expected features of T of F

Question 14

When may cardiac catheterisation be needed in the investigation of T of F?

Answer 14

To show detailed anatomy of coronary arteries

Question 15

What are some differential diagnoses of T of F?

Answer 15

• Other cyanotic congenital heart defects
• Pulmonary stenosis
• VSD

Question 16

What is the initial management of T of F?

Answer 16

Medical management

Question 17

What is the role of medical management in T of F?

Answer 17

To cover until surgery is performed at around 6 months of age

Question 18

What surgical correction of T of F involve?

Answer 18

• Closing the VSD

- Relieving right ventricular outflow obstruction

Question 19

What is sometimes used to close the VSD?

Answer 19

An artifical patch

Question 20

What may neonates who are very cyanosed require?

Answer 20

A shunt to increase pulmonary blood flow

Question 21

How is a shunt inserted to cyanosed infants?

Answer 21

Surgical placement of an artificial tube between the subclavian artery and the pulmonary artery or sometimes by ballon dilation in the right ventricular outflow tract

Question 22

How are hypercyanotic spells usually reversed?

Answer 22

They are usually self-limiting and followed by a period of sleep

Question 23

When may a hypercyanotic spell require treatment?

Answer 23

When they are prolonged (beyond around 15 mins)

Question 24

How may hypercyanotic spells treated?

Answer 24

• Sedation and pain relief
• IV propranolol
• IV volume administration
• Bicarbonate to correct acidosis
• Muscle paralysis and artificial ventilation

Question 25

What are some complications of T of F?

Answer 25

• MI

- Cerebrovascular accidents