Tetralogy of Fallot Flashcards
Approach to patient with repaired TOF
- Multiple surgical scars - midline sternotomy, previous surgical tubes, left chest extending anterior to posterior, etc
- Cyanosis (indicates severity)
- Digital clubbing
- Right ventricle heave
- Pulmonary ESM with thrill over upper LSE (residue pulmonary stenosis) or,
5A. Pulmonary EDM (pulmonary regurgitation) - Right heart failure (indicates severity) - elevated JVP, lower limb oedema
Approach to patient with unrepaired TOF with BT shunt
- Central cyanosis - TOF and even with BT shunt, but not present in repaired TOF
- Digital clubbing
- Features of BT shunt
- Diminished left radial pulse
- Left arm smaller than right
- Blood pressure lower in left arm
- Thoracotomy scar over the left
(If BT shunt placed over the right, then right side will be weaker and affected) - Absent a wave - in TOF or in AF
- Apex beat undisplaced
(if displaced, suspect severe RV hypertrophy or AR) - Parasternal heave - RVH
- Systolic thrill at ULSE (pulmonary)
- Palpable 2nd heart sound A2 (palpable after carotid)
- Single second heart sound A2 - reduced pulmonary component
- ESM at ULSE louder on inspiration (PS)
- Soft EDM at URSE (aortic) louder on sitting forward in expiration (AR)
- Continuous murmur over left subclavicular area and posteriorly (BT shunt)
Investigations for TOF
- Electrocardiogram (ECG) - SR, RAD, RAH, RVH, RBBB
- CXR
- Coeur en sabot (boot shaped heart)
- Reduced pulmonary vasculature
- Right sided aortic arch - Echocardiogram (TTE) - pulmonary stenosis, EF
- Cardiac catheterisation - pulmonary hypertension
Differential diagnoses and complications of TOF
(Stem as new onset chest pain / SOB)
- Differentials for the murmur - say AS, PS, VSD, MR
- Eisenmenger’s syndrome
- Partially repaired TOF with residue pulmonary stenosis (or unrepaired TOF in poor resourced countries)
- Pulmonary regurgitation
- Pulmonary hypertension
- Poor growth
- Infective endocarditis
- Cerebral abscess
- Polycythaemia
- Systemic thrombosis and paradoxical embolism
What are the complete syndromes of TOF?
- VSD
- Overriding aorta
- Pulmonary stenosis
- Right ventricular hypertrophy
Management of TOF
Surgical
1. Temporary - Blalock-Taussig shunt
- Left subclavian artery anastomosed to left pulmonary artery
- Relieves cyanosis and helps babies get enough oxygen
2. Complete repair
- VSD closure
- Pulmonary valve repair or replacement
- Enlarging pulmonary arteries
Medical management of “new symptoms” in PACES
1. Heart failure management and GDMT
2. Pulmonary valve repair
What are the risk factors/associations with TOF?
- Fetal hydantoin syndrome
- Fetal carbamazepine syndrome
- Fetal alcohol syndrome
- Maternal phenylketonuria
- Alagille syndrome
- CATCH 22 malformation
What are the precipitating causes of cyanotic spells?
- Exercise
- Fever
- Catecholamine release (stress)
- Hypoxia
- Dehydration
- Acidosis
Describe the pathophysiology of cyanotic spells
Infundibular spasms and decreased systemic vascular resistance increases right ventricular outflow obstruction
Increased right to left shunting and cyanosis
Murmur lessens in intensity as outflow gradient increases
How do you differentiate TOF from Eisenmenger’s syndrome clinically?
How do you differentiate isolated pulmonary stenosis from that of TOF pulmonary stenosis?
Isolated PS - prominent ‘a’ wave
TOF - absent ‘a’ wave
How do you differentiate continuous murmur of BT shunt from PDA?
- Clinical features of TOF
- Thoracotomy scar and absent left radial pulse
