Paediatric Cardiology Flashcards
Part 1 Foetal Circulation
part 1
describe foetal circulation?
A vein is a vessel carry oxygenated blood to heart from placenta
Umbilical and pulmonary veins both carry oxygenated blood
Systemic veins carry deoxygenated blood
Umbilical vein passes through ductus venosus in liver (closes after delivery and becomes ligamentous rotundum)
Mixing of deoxygenated and oxygenated blood from superior and inferior vena cava in the right atrium
Most blood then passes from the right atrium to the left atrium through foramen ovale
Blood passes from pulmonary trunk to aorta – in utero we have a right to left shunt
The shunts that bypass the lungs are called the foramen ovale, which moves blood from the right atrium of the heart to the left atrium, and the ductus arteriosus, which moves blood from the pulmonary artery to the aorta
part 1
What changes occur in the Fetal Circulation at Birth?
- Pulmonary Vascular Resistance Falls
- Pulmonary Blood Flow Rises
- Systemic Vascular Resistance is Increased
- Ductus Arteriosus Closes (closes within minutes)
- Foramen Ovale Closes
- Ductus Venosus Closes
If things were to stay open we would get a left to right shunt
part 1
what is a Patent Ductus arteriosus (Botalli)?
Patent ductus arteriosus (PDA) is a medical condition in which the ductus arteriosusfails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta, which has a higher pressure, to the pulmonary artery
part 1
what is the management of Patent Ductus arteriosus (Botalli)?
- Very common in pre-term infants
- treatment with fluid restriction/diuretics, prostaglandin inhibitors (Indomethacin, Ibuprofen), surgical ligation (relatively easyprocedure)
- In term babies good chance of spontaneous closure (in first year of life), not prostaglandin sensitive (so not a treatment option)
Patency controlled by prostaglandins - a group that favour closure and another group that keep it open
If prostaglandin synthesis is inhibited, then the pro closure prostaglandins would win
Part 2 - Pulmonary and Aortic Valve Stenosis
Part 2
Pulmonary and Aortic Valve Stenosis: Most common valvular problem in childhood
which is more common?
Pulmonary slightly more than aortic
Part 2
what is pulmonary stenosis
Pulmonary stenosis (also called pulmonic stenosis) is when the pulmonary valve (the valve between the right ventricle and the pulmonary artery) is too small, narrow, or stiff. Symptoms of pulmonary stenosis depend on how small the narrowing of the pulmonaryvalve is
Part 2
what are the symptoms of pulmonary stenosis?
- Asymptomatic in mild stenosis, in moderate and severe exertional dyspnoea and fatigue
- Ejection systolic murmur upper left sternal border with radiation to back
Children tend to be asymptomatic so tend to follow up ever 2/3 years to see if it progresses
If it dose then intervention necessary when at moderate stage
Part 2
pulmonary stenosis - most common intervention is what?
Most common intervention is balloon valvoplasty
Part 2:
what is balloon valvoplasty?
Most severe cases of pulmonic stenosis can be treated with a balloon valvuloplasty during heart catheterization. With this procedure, a doctor threads an unopened balloon through the pulmonary valve and inflates it to open the valve
to the level of the pulmonary valve and then its blown up and stretches the valve
Stenosis usually due to adhesions between the cusps of the valve in the periphery
Damage to the cusps in ballooning can occur so this does improve stenosis but this means there will be regurgitation of the valve
Pulmonary regurgitation can be tolerated well in children
Part 2:
valve replacement can also be done in pulmonary stenosis, how should it be done?
Valve replacement may have to be considered but this is uncommon in children, try delay this till after puberty to when child has stopped growing, due to heart being smaller and further valve placements may end up having to be made in the future
As you operate close to the electrical system of the heart, damage to conduction of electrical activity from the atria to the ventricles could occur
Part 2:
what is aortic stenosis
Aortic stenosis (AS or AoS) is the narrowing of the exit of the left ventricle of the heart (where the aorta begins), such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse over time
2nd most common valvular problem in childhood
Often a incidental finding of a murmur like pulmonary valve stenosis
Part 2:
what are the symptoms of aortic stenosis?
- Mostly asymptomatic, if severe, reduced exercise tolerance, exertional chest pain, syncope
- Ejection systolic murmur upper right sternal border, radiation into carotids
(Looking at heart form above, Aortic valve in centre)
Part 2:
how do you treat aortic stenosis?
Treatment similar to pulmonary valve stenosis
Balloon valvuloplasty can be attempted
Problem with aortic stenosis is your dealing with a high pressure environment meaning regurgitation after balloon is more common and not as well tolerated and valve replacement is often required earlier
Synthetic valves can be used but you can use the pulmonary valve and transplant it to the aortic valve and then put a artificial one into the pulmonary artery, pulmonary valve doesn’t work well in high pressure environments so not a definitive surgery