Cyanotic Heart Diseases

Question 1

What are the 5 main cyanotic heart diseases

Answer 1

1. Truncus arteriosus
2. Transposition of the great arteries
3. Tricuspid atresia
4. Tetralogy of fallot
5. Total anomalous pulmonary vascular return (TAPVR)

Question 2

How does cyanotic heart disease generally present

Answer 2

Blue baby
Feeding problems or failure to thrive
Exertional dyspnoea/tachypnoea
Hypoxaemia
Symptoms of HF
Nail clubbing

Question 3

What test can be done when a cyanotic baby does not respond to oxygen supplementation

Answer 3

Hyperoxia/nitrogen washout test
1. Infant given 100% O2 for 10 minutes
2. ABG taken
3. PO2 <15kPa = cyanotic heart disease

Question 4

What are the most likely causes of cyanosis according to timeline

Answer 4

within minutes - TGA
Days - Tricuspid atresia
Months - tetralogy of fallot

Question 5

Describe truncus arteriosus

Answer 5

Pulmonary artery and aorta become one vessel
Survival depends on the presence of a shunt - VSD

Question 6

What is transposition of the great arteries and its risk factors

Answer 6

Anatomical reversal of the aorta and pulmonary artery → two closed loop systems

Fatal unless there is a shunt
- intracardiac (PFO/VSD/ASD)
- extracardiac (PDA)

RF: maternal diabetes

Question 7

How does transposition of the great arteries present (symptoms and signs)

Answer 7

Postnatal cyanosis at rest (within minutes of birth)
Unaffected by supplemental oxygen
Tachypnoea
No murmur heard
Prominent right ventricular impulse

Question 8

Investigation and Management of Transposition of the great arteries

Answer 8

CXR: Egg on a string sign (cardiomegaly)

Immediate pGE1 infusion e.g. alprostadil
or
Balloon septoplasty (artificial VSD)
→ 2 weeks later - surgery

Question 9

What is tricuspid atresia

Answer 9

Absence of the tricuspid valve

Fatal unless there is a shunt (ASD + VSD)

Question 10

How does tricuspid atresia present (Symptoms and Signs)

Answer 10

Central cyanosis

Pansystolic murmur (Due to ASD and VSD)

Question 11

How is tricuspid atresia managed

Answer 11

Immediate PGE1 infusion e.g. alprostadil
→ 2 weeks - surgery

Question 12

What is tetralogy of fallot

Answer 12

Simultaneous occurrence of 4 defects:
1. Right ventricular outflow tract obstruction (RVOTO) - pulmonary stenosis
2. Right ventricular hypertrophy
3. Ventricular septal defect (large)
4. Overriding aorta - shifts to sit on top of the VSD

Question 13

What are the risk factors for tetralogy of fallot

Answer 13

DiGeorge Syndrome
Down’s syndrome
Maternal diabetes and alcohol consumption

Question 14

How does tetralogy of fallot present (symptoms and signs)

Answer 14

Severe cyanosis (depending on RVOTO extent)
2-4 months: Hypercyanotic tet spells in response to stress (pain, crying, feeding)

Untreated: squatting relieves symptoms

Harsh ejection systolic murmur heard

Question 15

What are the investigations and management for tetralogy of fallot

Answer 15

CXR: boot-shaped heart
ECG: RVH/Right axis deviation

Knee-chest position
High flow oxygen
Severe: PGE1 → surgical intervention within the 1st year

Question 16

What is total anomalous pulmonary venous return

Answer 16

The pulmonary veins merge to form a connecting vein that drains into the systemic venous circulation e.g. vena cava instead of the left atrium

Survival depends on a shunt - usually ASD, sometimes PDA

Question 17

What is Ebstein’s anomaly and what are its risk factors

Answer 17

Atrialisation of the right ventricular, where the tricuspid valve is displaced downwards → small and hypocontractile RV → tricuspid regurg → RA dilation → RHF

In-utero lithium exposure

Question 18

How does Ebstein’s anomaly present

Answer 18

Depends on the degree of displacement
Mild: cyanosis
Severe: in-utero hydrops fetalis

Pansystolic murmur
Mid-diastolic murmur

Question 19

Ebstein’s anomaly investigations and management

Answer 19

Echo: confirms
CXR: cardiomegaly (RA enlargement)

Surgery

Question 20

What are ductal dependent conditions and how are they managed

Answer 20

A heart condition that requires a patent PDA to sustain systemic blood flow

Systemic blood flow:
- Transposition of the great arteries
- Coarctation of the aorta

Pulmonary blood flow:
- Tricuspid atresia
- Severe RVOTO i.e. in tetralogy of fallot

Management = PGE1 infusion