Tetralogy of Fallot is a ventricular septal defect with over-riding aorta and right ventricular (RV) outflow tract obstruction and resulting RV hypertrophy. The common embryological cause for this constellation of findings is anterior and cephalad deviation of the muscular outlet of the ventricular septum.
Usually presents in the neonatal period with a murmur, cyanosis, or both.
Diagnosed by echocardiography.
Treatment is by surgical repair. This usually consists of complete intracardiac repair typically during the neonatal or infant period. Occasionally, an aortopulmonary shunt is used palliatively before complete repair.
The most common long-term complications of complete repair are progressive pulmonary regurgitation and RV failure, atrial arrhythmias, and ventricular arrhythmias.
Tetralogy of Fallot (TOF) is a congenital cardiac malformation. The key morphological abnormality is anterior and cephalad deviation of the muscular outlet of the ventricular septum, which causes the 4 classic findings: (1) a mal-alignment ventricular septal defect (VSD), (2) aorta over-riding the VSD, (3) right ventricular outflow tract obstruction, (4) secondary concentric right ventricular hypertrophy.
This was classically described by Dr. Etienne-Louis Arthur Fallot, a pathologist, who described it in 1888 and coined the term 'la maladie bleue' (blue-baby syndrome). The cyanosis associated with this condition is due to right-to-left shunting of de-oxygenated blood at the level of the VSD. Historically, children with TOF presented with cyanosis that was progressive and life-limiting; untreated children with TOF would typically squat down, which would lead to increased pulmonary blood flow.
History and exam
Key diagnostic factors
- hypercyanotic episodes
- harsh systolic ejection murmur
Other diagnostic factors
- trisomy 21, 18, or 13
- chromosome 22q11 deletions (DiGeorge's syndrome)
- Jagged1 gene mutations (Alagille's syndrome)
- mutation in NKX2.5 gene
- environmental factors
- family history of congenital heart disease
1st investigations to order
- pulse oximetry
- hyper-oxygenation test
Investigations to consider
- cardiac catheterisation
infant with non-remitting severe cyanosis
neonate with profound cyanosis and severely limited pulmonary blood flow
- Other cyanotic congenital cardiac abnormalities
- Pulmonary stenosis
- Ventricular septal defect (VSD)
- ESC guidelines for the management of adult congenital heart disease (previously grown-up congenital heart disease)
- 2018 AHA/ACC guidelines for the management of adults with congenital heart disease
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