Fallot's Tetralogy Flashcards
Which anatomical structures are affected by Fallot’s Tetralogy?
- ventricular septum
- pulmonary valve
- aorta
- right ventricle
Which physiological process is affected by Fallot’s tetralogy?
the sequential flow of deoxygenated blood through the right heart to the lungs and oxygenated blood through the left heart to the body
What are the 4 structural defects associated with Fallot’s tetralogy?
- ventricular septal defect
- pulmonary stenosis
- overriding aorta
- right ventricular hypertrophy
What is the VSD?
a hole in the heart
What is pulmonary stenosis?
Narrowing of the pulmonary valve
What is overriding aorta?
The position of the aorta is over the right ventricle as well as the left
What is right ventricular hypertrophy?
The wall of the right ventricle becomes more muscular due to high pressure
Why do patients with Fallot’s tetralogy have low oxygenation of blood?
This is due to the mixing of oxygenated and deoxygenated blood in the left ventricle via the VSD
What is the right-to-left shunt in Fallot’s tetralogy patients?
Preferential flow of the mixed blood from both ventricles through the aorta
Due to the obstruction to flow through the pulmonary valve
What causes Fallot’s tetralogy?
It is congenital but is believed to be caused by both genetic and environmental factors
What is the primary symptom of Fallot’s tetralogy?
Low blood oxygen saturation with or without cyanosis
What is cyanosis?
Blue appearance due to low level of oxygen in arterial blood
What are other symptoms of Fallot’s tetralogy?
- difficulty feeding
- failure to gain weight
- retarded growth and physical development
- dyspnoea on exertion
What clinical signs are visible in patients with Fallot’s tetralogy?
- heart murmur
- clubbing of fingers and toes
- polycythaemia
- “tet spells”
What does the heart murmur sound like?
It can range from almost imperceptible to very loud
What is polycythaemia?
Large amount of red blood cells
What happens during a “Tet spell”?
Sudden, marked increase in cyanosis followed by syncope
May result in hypoxic brain injury and death
How do older children react to a “Tet spell” and why?
They squat
This increases systemic vascular resistance and allows for a temporary reversal of the shunt
What will an echocardiogram of a patient with Fallot’s tetralogy show?
The abnormal anatomy
The Eisenmenger complex
What is the Eisenmenger complex?
A shunt of blood initially passes from left to right
Later on it will begin to shunt from right to left
What will an X-ray look like of a patient with Fallot’s tetralogy?
Abnormal “coeur-en-sabot” appearance (boot-like) of the heart
What treatment is given for “Tet spells”?
Why?
Oxygen
It is a potent pulmonary vasodilator and systemic vasoconstrictor
This allows more blood flow to the lungs
What surgical procedure is performed for early management of a baby with Fallot’s tetralogy?
Forming an anastomosis (join) between the subclavian artery and pulmonary artery
This allows more blood to get to the lungs
What is the purpose of curative heart surgery in patients with Fallot’s tetralogy?
It is designed to relieve the right ventricular outflow tract stenosis by removal of muscle and repair of the VSD
Despite surgery, what do patients remain at increased risk of?
sudden cardiac death and heart failure
