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
Part 3: Coarctation of the aorta
Part 3
what is coarctation of the aorta?
Coarctation of the aorta is a birth defect in which a part of the aorta is narrower than usual. If the narrowing is severe enough and if it is not diagnosed, the baby may have serious problems and may need surgery or other procedures soon after birth
Important to recognise early as can cause problems to new born baby
Means narrowing of a segment of aorta, usually on the descending part of the arch of the aorta,
Usually narrowing just where ductus enters aorta and this is important as a delayed closure of the duct can delay recognition of this in babies
Part 3
what is the clinical presentation of coarctation of the aorta?
Systolic murmur also on the left sternal edge
Very common presentation is sudden deterioration and collapse of the baby
Part 3
images of coarctation fo the aorta
Suprasternal echocardiogram of the aorta
Looks down onto aortic arch
Echo bright structure on descending end just before the left subclavian artery leaves the aorta
Flow acceleration in the lower middle
Part 3
MRI of coarctation of aorta
Can see tissue bridge at tip of arrow
Part 3
what happens in coarctation if the duct closure is delayed?
Often duct closure is delayed in those children so blood from the aorta which is narrowed will flow through the ductus arteriosus into the pulmonary trunk, this means the work load of the left ventricle is reduced and the baby may be coping
Part 3
what happens when the ductus finally closes in coarctation of the aorta?
Often able to feel some femoral pulse but will be weak
Duct closes 2-3 weeks after baby has been born meaning no bypass of the blood so the left ventricle has to pump hard against the severe obstruction of the coarctation, leads to a decreased CO and acute dilatation of the left ventricle and means baby will become unwell suddenly and collapse
These babies rushed into emergency department and collapsed baby is often treated as a septic baby until someone thinks of feeling for femoral pulse and they are now not palpable
part 3
what is the management of coartctation of the aorta?
- Re-open PDA with Prostaglandin E1 or E2 (this stabilises baby)
- Resection with end-to-end anastomosis
- Subclavian patch repair
- Balloon Aortoplasty (picture)
Part 4: Cyanotic Heart Defects
Part 4
what are cyanotic heart defects?
Cyanotic defects are defects in which blood pumped to the body contains less-than-normal amounts of oxygen, resulting in a condition called cyanosis. It causes a blue discoloration of the skin. Infants with cyanosis are often called “blue babies.”
Look for central cyanosis (blue lips and tongue of baby) – easy missed
Duct dependant – may be delayed
Central cyanosis almost always due to a cyanotic heart defect and signifies a left to right shunt
Part 4
what is transposition of the great arteries?
a birth defect of the heart in which the two main arteries carrying blood out of the heart – the main pulmonary artery and the aorta – are switched in position, or “transposed.” Because a baby with this defect may need surgery or other procedures soon after birth
Aorta from RV and pulmonary artery from the LV
If no shunt between these circulations then the baby wont survive long as no oxygenation takes place
Part 4
what is the management of transposition of the great arteries?
Mostly recognised antenatally
Give prostaglandins to keep duct open to ensure baby can be stabilised
If duct close then do surgery to open foramen ovale to allow blood mixing on atrial level
The immediate management of an infant with transposition focuses on establishing safe oxygen levels and stable cardiac and pulmonary function.
A continuous infusion of prostaglandin, a medication that will keep the ductus arteriosus open, is usually initiated when the diagnosis is suspected or confirmed. This will allow some mixing of oxygen-rich blood with oxygen-poor blood but may provide adequate mixing by itself
Although babies can be stabilized temporarily, surgical correction of the defect is always necessary. In most cases of transposition, an arterial switch operation is performed
Part 4
switch procedure for transposition/arterial switch operation - what is it?
The arterial switch operation involves cutting off the aorta and pulmonary arteries just above the point where they leave the heart, and reconnecting them to the proper ventricle. The valve stays attached to the ventricle, so what was once the pulmonary valve is now the aortic valve and vice versa
Definitive procedure
Cutting vessels off their origins
Part 4
Switch procedure for transpositionMain problem is the coronary arteries as they are thread like and tiny at that age and cannot be damaged in any way as would lead to MI
how is this delt with?
Since the coronary arteries must stay with the aorta, they must be taken off the area above the valve and reimplanted separately above the new aortic valve. This is often the most technically challenging part of the operation, particularly if there is unusual branching of these arteries
Patch is cut out around coronary arteries and plugged into the big vessel stump on the left side
Once switch procedure has been preformed, the outlook is good
Part 4
what is Fallot’s Tetralogy?
Boot shaped heart
Lifting of apex of heart due to right ventricular hypertrophy
Tetralogy of Fallot is a combination of four congenital abnormalities. The four defects include a ventricular septal defect (VSD), pulmonary valve stenosis, a misplaced aorta and a thickened right ventricular wall (right ventricular hypertrophy)
Right ventricular hypertrophy due to reduced outflow so pressure is very high and this leads to right to left shunt so the baby will become centrally cyanosed
Part 4
what is the management of Tetralogy of Fallot?
VSD is closed with a patch and aorta restored to left ventricle only
Infundibulum leading upto the pulmonary valve will be widened
Pulmonary valve will be opened surgically
RVOT can start narrowing again and may need operation
One provides temporary improvement by a shunt to give more blood flow to the lungs - Can make a shunt between one of the subclavian arteries with the ipsilateral pulmonary artery
The surgeon closes the ventricular septal defect with a patch and opens the right ventricular outflow tract by removing some thickened muscle below the pulmonary valve, repairing or removing the obstructed pulmonary valve and, if needed, enlarging the branch pulmonary arteries that go to each lung
Extra
what syndrome cause congenital heart defects?
Extra
what are the 3 main types of ventricular septal defects?
- subaortic
- perimembranous
- muscular
L to R shunt
Extra
what is the clinical presentation of ventricular septal defects?
- Pansystolic murmur lower left sternal edge, sometimes with thrill
- In very small VSDs, early systolic murmur
- In very large VSDs diastolic rumble due to relative mitral stenosis
- Signs of cardiac failure in large VSDs, eventually leading to biventricular hypertrophy and pulmonary hypertension
Extra
what is Eisenmenger Syndrome?
a condition that results from abnormal blood circulation caused by a defect in the heart. Most often, people with this condition are born with a hole between the two pumping chambers – the left and right ventricles – of the heart (ventricular septal defect)
Extra
how is VSD closure done?
- Amplatzer or other occlusion device, trans-catheter
- Patch closure, open heart surgery
extra
how does atrial septal defects present?
- Few clinical signs in early childhood, good chance of spontaneous closure
- Sometimes detected in adulthood with atrialfibrillation, heart failure or pulmonary hypertension
- Wide fixed splitting of 2nd heart sound, pulmonary flow murmur
extra
Atriovetriculo-septal defect or endocardial cushion defect or AV canal defect - what is it associated with?
- Associated with Trisomy 21
- Singular AV valve with ostium primum ASD and high VSD
