Tetralogy of Fallot

Question 1

Define TOF

Answer 1

congenital heart condition involving 4 co-existing pathologies

Question 2

PROV

What are the 4 pathologies in TOF?

Answer 2

• Pulmonary valve stenosis
• Right ventricular hypertrophy
• Overriding aorta
• Ventricular septal defect (VSD)

Question 3

In terms of cyanosis, what type of congenital heart condition is TOF?

Answer 3

Cyanotic

Question 4

What does an increase R-L shunt leads to in TOF

Answer 4

‘Tet Spells’ - sudden increase in the obstruction of the right ventricular outflow tract

Question 5

‘Tet’ spells triggers

Answer 5

• Exercising
• Crying
• Feeding

Question 6

How do the knee-chest position relive a ‘Tet’ spell

Answer 6

increase systemic vascular resistance, which can reduce the right-to-left shunting and improve blood flow to the lungs.

Question 7

‘Tet’ spells Sx

Answer 7

• Cyanosis: blue skin/lips
• Tachypnoea
• Lethargy
• Syncope
• Knee-chest position
• Tachycardia
• Clubbing: chronic Sx

Question 8

What type of murmur is found in TOF

Answer 8

ejection systolic murmur at the left sternal edge (pulmonary valve)

Question 9

Conservative Mx for Tet spell

Answer 9

• Knee-chest position to increase systemic resistance and reduce the right-to-left shunt.
• Soothing the child to reduce agitation and stress.

Question 10

Medical Mx for Tet spells

Answer 10

• Oxygen administration to increase oxygen levels in the blood.
• Morphine to reduce heart rate and right ventricular pressure.
• Intravenous fluids if needed for hydration and blood volume support.
• Beta-blockers (such as propranolol) to decrease heart rate and improve oxygenation.
• Sodium bicarbonate for severe acidosis.
• Phenylephrine (vasopressor) to increase systemic vascular resistance

Question 11

TOF CXR findings

Answer 11

• Boot-shaped heart: RVH
• Reduced pulmonary vascular markings: Reduced blood to lungs
• Enlarged RV:

Question 12

What anatomical anomaly determines the extent of cyanosis in TOF

Answer 12

The degree of right ventricle outflow obstruction correlates to the extent of cyanosis caused.

Question 13

ECG findings for TOF

Answer 13

• RVH: tall R waves in V1, deep S waves in V6
• R Axis dev: thumb rules V1/aVF

Question 14

When is TOF usually identified

Answer 14

During antenatal scans

Question 15

TOF clinical presentations

Answer 15

Shortness of breath
Cyanosis
Finger clubbing
Poor feeding
Poor weight gain
Tet spells (intermittent episodes of cyanosis)

Question 16

What Ix can be used to identify the direction of blood flow in TOF

Answer 16

Doppler

Question 17

Tet spell complications

Answer 17

• Syncope
• Seizures
• Death