Paediatric Cardiology Flashcards
Via what vessel does oxygenated blood get from the placenta to the foetus? Where does this vessel anastamose onto?
Umbilical vein
Becomes the ductus venosus and then anastamoses onto the inferior vena cava
Where is the ductus venosus? What is its function? What does it become after birth?
It passes through the fetal liver
It transports blood from the umbilical vein to the inferior vena cava
Closes and becomes the ligamentum rotundum of the liver
What sort of blood (oxygenated / deoxygenated) enters the right atrium of the fetus? Where does most of it tend to go from there?
A mixture - deoxygenated from the SVC, oxygenated from the IVC
Goes through the foramen ovale into the left atrium - left ventricle
How does the foetal circulation account for the fact that the lungs don’t require much oxygen?
Any blood into the pulmonary artery faces high resistance due to the lungs not being developed
It gets forced through the ductus arteriosus, an anastamosis between the pulmonary artery and the aorta
What are the changes in fetal circulation that occur at birth?
- Pulmonary vascular resistance falls & blood flow rises
- Systemic vascular resistance is increased
- Ductus arteriosus closes
- Foramen ovale closes
- Ductus venosus closes
How is patent ductus arteriosus treated in preterm infants?
- Fluid restriction / diuretics
- Prostaglandin inhibitors: ibuprofen / indometacin
- Surgical: ligation of the patent duct
How is patent ductus arteriosus treated in in term infants?
Spontaneous closure often happens within a year, so would reassess at a year:
- If “silent” patent DA: would not treat, haemodynamically irrelevant
- If symptomatic duct: catheter closure with umbrella device
How do you decide if the patent DA is symptomatic or silent?
If it is silent you won’t hear the murmur, if it is symptomatic you will
How do children with pulmonary valve stenosis tend to present? What clinical signs may be seen? Investigations?
Mild stenosis - asymptomatic
Moderate-severe - exertional dyspnoea & fatigue
Ejection systolic murmur may be heard on upper left sternal border with radiation to back
ECHO to investigate
Treatment for pulmonary stenosis in children?
Balloon valvoplasty
Catheter placed through the femoral vein, to the pulmonary valve. Then inflate the balloon at the end of the catheter when there
What is one complication associated with balloon valvoplasty for aortic stenosis in children?
Pulmonary regurgitation occurs
Tends to be well tolerated in children
Valve replacement may be necessary eventually but try to delay these until after growth has stopped, due to the change in size of the heart as the child grows
What is one complication to be aware of that may occur when performing valve replacement surgery?
Scar tissue formation leading to interruption in conductance in the electrical system of the heart
How long do replacement heart valves tend to last?
10-15 years
(20 if you’re lucky)
- Surgery becomes more complex after each replacement
How do children with aortic valve stenosis tend to present? What clinical signs may be seen? Investigations?
Mild - asymptomatic
Mod-severe - reduced exercise tolerance, exertional chest pain, syncope
Ejection systolic murmur at the upper right sternal border, radiation to carotids
ECHO
How is aortic stenosis treated? What is different about its management when compared to pulmonary stenosis?
Balloon valvoplasty
Aortic regurgitation due to valvoplasty isnt as well tolerated and so valve replacement is often required much earlier on
What is the Ross-Konno procedure?
Replacing the aortic valve with the pulmonary valve and then placing a biosynthetic valve in place of the pulmonary valve
The pulmonary valve isn’t meant for high pressure environments though so will need to be replaced again eventually
Where does the coarctation of the aorta tend to occur?
Where the ductus arteriosus closes
Delayed closing of the duct can delay recognition of aortic coarctation in babies
What is the clinical presentation of coarctation of the aorta?
Weak or absent femoral pulses
Radio-femoral delay (only in chronic coarctation - late sign)
Systolic murmur heard loudest on the back
Sudden deterioration and collapse of the patient
What investigations should be done for suspected coarctation of the aorta?
ECG - RV hypertrophy in the neonate, LV hypertrophy in older child
CXR - rib notching from collaterals
ECHO**
MRI
What conditions tend to occur with coarctation of the aorta?
Common in children with Turner syndrome
Often occurs alongside VSD
If a baby is in critical condition due to coarctation of the aorta what treatment should be given?
Prostaglandin E1 or E2 to keep the ductus arteriosus open, reduces the load on the LV
Then get the baby to cardio surgery centre: end to end resection and anastamosis
Aortic coarctation is often associated with hypoplasia of the aortic arch, how does this change treatment?
Often have to augment the aortic arch with part of the left subclavian to provide structural integrity
Then either end to end resection and anastamosis or balloon arthroplasty
Two main treatment options for coarctation of the aorta?
End to end resection and anastamosis
Balloon arthroplasty + stenting
What is the main sign of cyanotic heart defects?
Central cyanosis (blue lips + tongue)
What are some examples of cyanotic heart defects?
Transposition of the great arteries
What is transposition of the great arteries? How does it present?
Where the aorta comes out of the RV and the pulmonary artery comes out of the LV
Presents with cyanosis
What is the first step in managing the transposition of the great arteries?
IV prostaglandin to keep the ductus arteriosus open
If it isn’t kept open the likelihood of the babies survival is very low
What is a Rashkind procedure?
Insertion of a balloon catheter through the femoral vein into the RA, can be used to prevent the leaflets of the fossa ovalis from joining, allowing blood flow between atria
Done for congenital cyanotic heart defects such as transposition of the great arteries to allows blood mixing
What surgical procedure is done to treat transposition of the great arteries? What is the main challenge with the procedure & brief overview?
Switch procedure
Baby placed on cardiopulmonary bypass, aorta and pulmonary trunk are switched
The main challenge is switching the coronary arteries which are thread sized in babies, cut out a patch off the base of the new pulm. trunk and sew onto new aorta, then fill in patches in the lower pressure system
What are the four conditions that make up the tetralogy of Fallot?
- VSD
- Overriding aorta (into space of RV)
- Pulmonary stenosis
- RV hypertrophy (due to stenosis)
When does the tetralogy of Fallot need to be treated?
Usually babies do alright with it and are only treated at around 6 months when they’re about 5kg heavy
What is a Blalock-Taussig shunt?
A shunt created between the subclavian artery and the ipsilateral pulmonary artery
Allows greated blood flow to the lungs in babies suffering from tetralogy of fallot (needed bc pulm stenosis)
After the surgical correction of the tetralogy of Fallot how do babies tend to get on?
They tend to become uncyanosed
They require lifelong checkups though because the risk of the right ventricular outflow tract closing again is quite high
