Tetralogy of Fallot Flashcards
What is Tetralogy of Fallot?
A congenital cardiac malformation involving anterior and cephalad deviation of the muscular outlet of the ventricular septum resulting in 4 classical findings
What are the 4 classical findings of Tetralogy of Fallot?
- Large VSD
- Overriding aorta
- Sub-pulmonary stenosis
- Right ventricular hypertrophy
What kind of congenital heart disease is T of F?
Cyanotic
Why is T of F a cyanotic heart defect?
There is right to left shunting via the VSD due to the pulmonary stenosis and right sided hypertrophy
What are the risk factors for T of F?
- Trisomy 21, 18, or 13
- DiGeorge syndrome
- Alagille’s syndrome
- Mutation in NKX2.5 gene
When are most children with T of F diagnosed?
Antenatally or following identification of a murmur in the first 2 months
What are the clinical features of T of F?
- Hypercyanotic episodes
- Harsh systolic ejection murmur
- Cyanosis
- Tachypnoea
- Clubbing of fingers and toes in older children
What is a hypercyanotic episode?
Rapid increase in cyanosis with irritability or crying and breathlessness and pallor
When is the harsh systolic ejection murmur first heard?
From the first day of life
What will happen as right ventricular outflow obstruction increases?
The murmur will shorten and cyanosis will increase
What investigations can be used in T of F?
- CXR
- ECG
- Echo
- Cardiac cathaterisation
What will a CXR show in T of F?
- Relatively small heart
- Uptilted apex (boot shaped) due to right ventricular hypertrophy
- Right-sided aortic arch
- Pulmonary artery ‘bay’
- Decreased pulmonary vascular markings
What will an echo show in T of F?
Expected features of T of F
When may cardiac catheterisation be needed in the investigation of T of F?
To show detailed anatomy of coronary arteries
What are some differential diagnoses of T of F?
- Other cyanotic congenital heart defects
- Pulmonary stenosis
- VSD
What is the initial management of T of F?
Medical management
What is the role of medical management in T of F?
To cover until surgery is performed at around 6 months of age
What surgical correction of T of F involve?
- Closing the VSD
- Relieving right ventricular outflow obstruction
What is sometimes used to close the VSD?
An artifical patch
What may neonates who are very cyanosed require?
A shunt to increase pulmonary blood flow
How is a shunt inserted to cyanosed infants?
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
How are hypercyanotic spells usually reversed?
They are usually self-limiting and followed by a period of sleep
When may a hypercyanotic spell require treatment?
When they are prolonged (beyond around 15 mins)
How may hypercyanotic spells treated?
- Sedation and pain relief
- IV propranolol
- IV volume administration
- Bicarbonate to correct acidosis
- Muscle paralysis and artificial ventilation
What are some complications of T of F?
- MI
- Cerebrovascular accidents
