2: Cardio - Cyanotic Heart Defects Flashcards
What is cyanotic congenital heart disease
Congenital HD characterised by right-to-left shunt. Meaning deoxygenated blood enters oxygenated systemic. Hypoxaemia results as cyanosis
What are the 5 T’s of cyanotic HD
TOF TGA Tricuspid atresia Total anomalous pulmonary venous return Truncus arteriosus
What is tetralogy of fallot
Combination of four heart conditions
What is a way to remember 4 abnormalities in TOF
VORP
What are the four abnormalities in TOF
VSD
Over-riding aorta
Right ventricular hypertrophy
Pulmonary artery stenosis
What is the most common cyanotic congenital heart condition
TOF
What condition is TOF associated with
DiGeorge’s Syndrome
What is DiGeorge’s Syndrome
22q 11.2 deletion syndrome
How is TOF typically diagnosed
Antenatally
If not identified antenatally what age does TOF tend to present
1-2 months. Can be picked up to 6m afterwards
What are three clinical features of TOF
- Ejection systolic murmur
- Tet spells
- Squatting
What are tet spells
Intermittent, unpredictable episodes of tachypnoea, restlessness and cyanosis that lasts minutes-to-hours. Associated with physical stress.
Why do children with TOF squat
Squatting increases peripheral vascular resistance. This increases pressure in left-side of the heart reducing right-to-left shunt and subsequent hyperaemia.
What are three possible triggers for Tet spells
- Defecation
- Feeding
- Crying
What murmur is heard in TOF
Harsh ejection systolic murmur
Where is murmur in TOF loudest
Erb’s point or left-upper sternal edge
Where is Erb’s point
3rd IC space. Left lower sternal edge.
What causes the murmur in TOF
Pulmonary stenosis
What are two other signs of TOF
- Right ventricular heave
- Cyanosed w/clubbing
What is TOF caused by
Anterior misalignment of the aorticopulmonary septum
Explain why there is RVH in TOF
Pulmonary stenosis reduces outflow of blood. To try and maintain output right ventricle undergoes hypertrophy to increase pressure.
Why is there a right-to-left shunt in TOF
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.
What determines degree of cyanosis in TOF and why
Degree of pulmonary stenosis - as this determines extent of RVH and hence pressure in right ventricle.
At what SpO2 will a child develop cyanosis
<80%
What are three investigations in TOF
SpO2
CXR
ECG
What will be seen on CXR in TOF
Boot-shaped heart: due to RVH
What will be seen on ECG
RVH