Tetralogy_of_Fallot_Flashcards
What is Tetralogy of Fallot (TOF)?
TOF is the most common cause of cyanotic congenital heart disease. It typically presents at around 1-2 months, although may not be picked up until the baby is 6 months old.
What causes Tetralogy of Fallot?
TOF is a result of anterior malalignment of the aorticopulmonary septum.
What are the four characteristic features of Tetralogy of Fallot?
Ventricular septal defect (VSD), right ventricular hypertrophy, right ventricular outflow tract obstruction/pulmonary stenosis, overriding aorta.
What determines the degree of cyanosis and clinical severity in Tetralogy of Fallot?
The severity of the right ventricular outflow tract obstruction.
What are other features of Tetralogy of Fallot?
Cyanosis, episodic hypercyanotic ‘tet’ spells, tachypnoea, severe cyanosis, right-to-left shunt, ejection systolic murmur due to pulmonary stenosis, right-sided aortic arch in 25% of patients, ‘boot-shaped’ heart on chest x-ray, right ventricular hypertrophy on ECG.
What are ‘tet’ spells?
Episodic hypercyanotic spells due to near occlusion of the right ventricular outflow tract, causing tachypnoea and severe cyanosis that may occasionally result in loss of consciousness.
When do ‘tet’ spells typically occur?
When an infant is upset, is in pain, or has a fever.
What is the management for Tetralogy of Fallot?
Surgical repair is often undertaken in two parts. Cyanotic episodes may be helped by beta-blockers to reduce infundibular spasm.
summarise Tetralogy of Fallot
Tetralogy of Fallot
Tetralogy of Fallot (TOF) is the most common cause of cyanotic congenital heart disease*. It typically presents at around 1-2 months, although may not be picked up until the baby is 6 months old
TOF is a result of anterior malalignment of the aorticopulmonary septum. The four characteristic features are:
ventricular septal defect (VSD)
right ventricular hypertrophy
right ventricular outflow tract obstruction, pulmonary stenosis
overriding aorta
The severity of the right ventricular outflow tract obstruction determines the degree of cyanosis and clinical severity
Other features
cyanosis
unrepaired TOF infants may develop episodic hypercyanotic ‘tet’ spells due to near occlusion of the right ventricular outflow tract
features of tet spells include tachypnoea and severe cyanosis that may occasionally result in loss of consciousness
they typically occur when an infant is upset, is in pain or has a fever
causes a right-to-left shunt
ejection systolic murmur due to pulmonary stenosis (the VSD doesn’t usually cause a murmur)
a right-sided aortic arch is seen in 25% of patients
chest x-ray shows a ‘boot-shaped’ heart, ECG shows right ventricular hypertrophy
Management
surgical repair is often undertaken in two parts
cyanotic episodes may be helped by beta-blockers to reduce infundibular spasm
*however, at birth transposition of the great arteries is the more common lesion as patients with TOF generally present at around 1-2 months
Each one of the following is a feature of Tetralogy of Fallot, except:
Pulmonary stenosis
Overriding aorta
Ventricular septal defect
Atrial septal defect
Right ventricular hypertrophy
Atrial septal defect
