Paediatric Cardiology

Question 1

Part 1 Foetal Circulation

Question 2

part 1

describe foetal circulation?

Answer 2

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

Question 3

part 1

What changes occur in the Fetal Circulation at Birth?

Answer 3

• 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

Question 4

part 1

what is a Patent Ductus arteriosus (Botalli)?

Answer 4

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

Question 5

part 1

what is the management of Patent Ductus arteriosus (Botalli)?

Answer 5

• 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

Question 6

Part 2 - Pulmonary and Aortic Valve Stenosis

Question 7

Part 2

Pulmonary and Aortic Valve Stenosis: Most common valvular problem in childhood

which is more common?

Answer 7

Pulmonary slightly more than aortic

Question 8

Part 2

what is pulmonary stenosis

Answer 8

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

Question 9

Part 2

what are the symptoms of pulmonary stenosis?

Answer 9

• 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

Question 10

Part 2

pulmonary stenosis - most common intervention is what?

Answer 10

Most common intervention is balloon valvoplasty

Question 11

Part 2:

what is balloon valvoplasty?

Answer 11

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

Question 12

Part 2:

valve replacement can also be done in pulmonary stenosis, how should it be done?

Answer 12

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

Question 13

Part 2:

what is aortic stenosis

Answer 13

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

Question 14

Part 2:

what are the symptoms of aortic stenosis?

Answer 14

• 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)

Question 15

Part 2:

how do you treat aortic stenosis?

Answer 15

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

Question 16

Part 3: Coarctation of the aorta

Question 17

Part 3

what is coarctation of the aorta?

Answer 17

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

Question 18

Part 3

what is the clinical presentation of coarctation of the aorta?

Answer 18

Systolic murmur also on the left sternal edge

Very common presentation is sudden deterioration and collapse of the baby

Question 19

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

Answer 19

Flow acceleration in the lower middle

Question 20

Part 3

MRI of coarctation of aorta

Answer 20

Can see tissue bridge at tip of arrow

Question 21

Part 3

what happens in coarctation if the duct closure is delayed?

Answer 21

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

Question 22

Part 3

what happens when the ductus finally closes in coarctation of the aorta?

Answer 22

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

Question 23

part 3

what is the management of coartctation of the aorta?

Answer 23

• Re-open PDA with Prostaglandin E1 or E2 (this stabilises baby)
• Resection with end-to-end anastomosis
• Subclavian patch repair
• Balloon Aortoplasty (picture)

Question 24

Part 4: Cyanotic Heart Defects

Question 25

Part 4 what are cyanotic heart defects?

Answer 25

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

Question 26

Part 4 what is transposition of the great arteries?

Answer 26

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

Question 27

Part 4 what is the management of transposition of the great arteries?

Answer 27

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

Question 28

Part 4 switch procedure for transposition/arterial switch operation - what is it?

Answer 28

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

Question 29

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?

Answer 29

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

Question 30

Part 4 what is Fallot’s Tetralogy? Boot shaped heart Lifting of apex of heart due to right ventricular hypertrophy

Answer 30

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

Question 31

Part 4 what is the management of Tetralogy of Fallot?

Answer 31

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

Question 32

Extra what syndrome cause congenital heart defects?

Answer 32

Question 33

Extra what are the 3 main types of ventricular septal defects?

Answer 33

- subaortic - perimembranous - muscular L to R shunt

Question 34

Extra what is the clinical presentation of ventricular septal defects?

Answer 34

* 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

Question 35

Extra what is Eisenmenger Syndrome?

Answer 35

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)

Question 36

Extra how is VSD closure done?

Answer 36

* Amplatzer or other occlusion device, trans-catheter * Patch closure, open heart surgery

Question 37

extra how does atrial septal defects present?

Answer 37

* 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

Question 38

extra Atriovetriculo-septal defect or endocardial cushion defect or AV canal defect - what is it associated with?

Answer 38

* Associated with Trisomy 21 * Singular AV valve with ostium primum ASD and high VSD