1/2: Cardio - Acaynotic Heart Defects Flashcards
How is congenital heart disease in paediatrics divided
Into cyanotic or acyanotic congenital heart defects
What are 4 broad categories of causes of congenital heart disease
- Idiopathic
- Genetic
- Maternal illness - infection or underlying condition
- Maternal exposure to toxins in-utero
What 2 heart conditions is Turner’s Syndrome associated with
- Bicuspid aortic valve
- Coarctation aorta
What 4 heart conditions is DiGeorge’s Syndrome associated with
- TOF
- PDA
- VSD
- CA
What heart condition is William’s syndrome associated with
AS
What 2 heart conditions is rubella associated with
PS
PDA
What does congenital HD increase the risk of in children
Infective Endocarditis
What are the 4 acyanotic congenital heart defects
- ASD
- VSD
- Coarctation of the aorta
- Patent ductus arteriosus
What are the three cyanotic congenital heart defects
- TOF
- Tricuspid atresia
- TGA
What is a way to remember 4 acyanotic CHD
4D’s
What is a way to remember 3 cyanotic CHD
3T’s
Describe circulation in a foetus
- Oxygenated blood passes from mother into umbilical vein via placenta.
- Umbilical vein enters IVC by ductus venous
- Enters right atrium
- Blood right atrium passes to left atrium via foramen oval
- Some passes to right ventricle and out pulmonary.a
- Ligamentum arteriosum in pulmonary.a shunts blood to aorta
- Umbilical vein originates fro, internal iliac
Explain changes in circulation at birth
- Clamping of the umbilical cord increases systemic vascular resistance
- As baby breathes air, alveoli expand and surrounding vessels dilate due to oxygenation. This reduces pulmonary pressure. Reduction in pulmonary pressure increases blood flow to the lungs and hence decreases flow through ductus arteriosus which closes at 10-15h following birth
- Increase systemic vascular resistance increases pressure in right atrium > left atrium causes closure of foramen ovale within 3 minutes
Is peripheral cyanosis a normal or abnormal finding in first 24h
Normal
Is central cyanosis normal or abnormal finding in first 24h
Abnormal
What does central cyanosis indicate
deoxygenated Hb concentration >5
What is used to distinguish respiratory from cardiac causes of neonatal cyanosis
Nitrogen wash out test
What is the nitrogen wash out test
- Baby is given 100% oxygen for 10-minutes then an ABG given to measure PaO2
- If respiratory cause, oxygen should mean deficit resolves. In cardiac cause, additional oxygen will not help
What does a PaO2 of <15kPa indicate on nitrogen wash out test
Cyanotic congenital heart disease is the cause of cyanosis
When is paediatric heart failure most common
3m life
How is does paediatric HF present
- Poor Feeding
- SOB
- Sweating
- FTT
- Sacral oedema (due to lying down)
What type of shunt is present in acyanotic heart disease
Left-to-Right Shunt
What are 5 causes of acyanotic heart disease
ASD VSD Patent Ductus arteriosus Coarctation of aorta Aortic stenosis
Explain general pathophysiology of acyanotic heart conditions
- Due to increased pressure in left side (systemic system) compared to right side blood is shunted left to right
- This means already oxygenated blood passes through pulmonary circulation again
- This can increase pressure in pulmonary circulation causing pulmonary HTN
What can acyanotic heart conditions eventually lead to
Eisenmenger syndrome
What is Eisenmenger syndrome
- Left-to-right shunt increases pulmonary pressure
- Leads to remodelling of pulmonary vasculature which results in permanent pulmonary HTN
- To compensate, right ventricle undergoes hypertrophy
- This increases right-sided pressure reversing shunt from right-to-left causing cyanotic HD
What are the two types of atrial septal defect
- Ostium primum
2. Ostium secondum
What is the most common type of ASD
Ostrium Secondum (70%)
What is the most common congenital HD found in adulthood
ASD
Which gender is ASD more common
Female (3:1)
What syndrome is osteum secondum ASD associated with
Holt-Oram Syndrome
What is holt-oral syndrome called
Hand-Heart Syndrome
What is heart-hand syndrome
Individual presents with ASD and tri-phalangeal thumb
How does ASD present clinically
Asymptomatic in majority.
May present with complications in 3rd-4th decade of life due to pulmonary HTN
How are ASD often detected
On incidental exam
How does osteum primum present
If large defect may present with heart failure
What is a palpable sign of ASD and why does this happen
Right ventricular heave - due to increased blood flow through right-side heart
What murmur is present in ASD and why does it happen
Ejection Systolic - due to increased/more blood flow through narrow (same-size) pulmonary valve causing turbulence
What HS is present in ASD and why does it happen
Split S2 - Due to more blood flow in left side of the heart it takes longer for pulmonary valve to close
Why is ostium primum more serious
As it involves endocardial tissue which is used to form mitral and tricuspid valves. Therefore is also associated with valve regurgitation.
Why is ostium secundum less serious than primum
Does not involve endocardial cushions used for valves
What is first-line investigation in suspected ASD
ECG
What will ECG show in a small shunt
Normal
What will ECG show in larger shunt
- P pulmonale
- Right axis deviation
What may a CXR show in ASD
Pulmonary plethora - evidence increased blood flow to lungs
What is diagnostic of ASD
ECHO
How is ostium primum managed
surgical closure before pre-school
How is ostium secundum managed
surgical closure before school age
How are ASD closed
Either via cardiac catheterisation or open heart surgery
Without repair what will happen in ostium primum
Lead to heart failure in childhood
Without repair what will happen in ostium secundum
Lead to heart failure in 3-4th decade life
What is the most common congenital HD
VSD
What % of congenital HD is VSD
25%
What are VSD caused by
- Chromosomal abberations
- Maternal toxins in-utero
- Congenital infection
What does clinical presentation of VSD depend on
Size
How will a small VSD present
Asymptomatic
How may a small VSD be found
Heart murmur on exam
What % of VSD spontaneously close
75% close by 10y
What is the main risk of small VSD
Infective endocarditis
When will medium VSD cause clinical symptoms
In infancy/childhood
What are the symptoms of medium VSD
Presents as heart failure
How will heart failure in infants present
- Poor feeding
- Increased work of breathing
- Failure to thrive
- Sacral oedema
What may precipitate symptoms in medium VSD
Infection as this increases cardiac demand
Explain prognosis of medium VSD
As the child grows, the VSD will get smaller and majority will close spontaneously. Medications are used at the time to relieve symptoms.
Explain symptoms of large-VSD
Presents in first-few days of life with heart failure
What is the complication of large VSD
If not closed surgically, Eisenmenger syndrome will ensue
What murmur is present in VSD
pan systolic
What is paradoxical about VSD
small the VSD and therefore less severe, louder murmur, due to more turbulence.
What is palpable in VSD
thrill
Where does VSD usually occur
pars membranacea - membranous part of ventricular septum
What shunt will defect in pars membranacea cause and why
left-to-right due to higher pressure in left side (systemic system)
What is used to investigate VSD
ECHO with doppler
How is small VSD managed
- Follow up ECHO
- Usually spontaneous closure
How is a symptomatic VSD managed
Treat HF: ACEi, B-blocker, Diuretics
What are the indications for surgical closure of VSD
- Pulmonary HTN and less than 1y
- Failure to control symptoms on medical management
What are 4 complications of VSD
- Aortic regurgitation
- Pulmonary HTN
- Right HF
- Eisenmenger complex
Why does aortic regurgitation occur in VSD
Defect in pars membranacea reduces support of aortic valve causing regurgitation
What is contraindicated in adults with pulmonary HTN and why
Pregnancy. Due to 30-50% associated mortality
What is patent ductus arteriosus
Failure of ductus arteriosus to close during post-natal period
In which gender is a patent ductus arteriosus more common
F (2:1)
What % of PDA is an isolated heart defect
90%
What % of PDA is associated with another heart anomaly
10%
What are three risk factors for PDA
- Rubella infection during first trimester
- Prematurity
- Baby born at high altitude
What are symptoms of a small PDA
Asymptomatic
How will a large PDA present
HF in infancy
What are the 2 symptoms of right-sided HF in infants
- Sacral oedema
- Hepatosplenomegaly
What are the symptoms of left-sided HF in infants
- Breathlessness
- Poor Feeding
- Recurrent LRTI (due to pulmonary congestion)
- Fatigue
- FTT
- Cold extremities (cyanosed)
What can be felt in PDA
- Heaving apex beat
- Left sub-clavicular thrill
What are three characteristics of pulse in PDA
- Bounding
- Wide pulse pressure
- Collapsing
Why is pulse collapsing in PDA
As with each systole, blood passes from aorta to pulmonary.a (lower pressure)
What murmur is heard in PDA
Continuous murmur through systole and diastole - described as machinery murmur
Where is the murmur in PDA loudest
Infra-clavicular region
What is the role of ductus arteriosus in the foetus
- In the foetus oxygen is obtained through placenta not foetal lungs
- Majority of blood in right atrium passes to left atrium by foramen ovale
- Remaining blood enters pulmonary.a. Shunted to aorta by ductus arteriosus
- Therefore bypass lungs
What keeps ductus arteiosus open in-utero
PGE2 released from the placenta and foramen ovale
What happens at birth to the ductus arteriosus
Placenta is removed. Foramen Ovale closes - reducing PGE2 secretion resulting in closure.
Once oxygenated, lungs release bradykinin that closes smooth muscle component of DA
When does the ductus arteriosus collapse to form the ligamentous arteriosum
3W
When is the ductus arteriosus regarded as patent
> 3W
Why is PDA acyanotic
As blood shunts from aorta into pulmonary.a down a pressure gradient. Therefore already oxygenated blood cycles
What is first-line investigation for PDA
ECG
What will be seen on ECG in small PDA
Normal
What will be seen on ECG in large PDA
Left axis deviation due to left ventricular hypertrophy
What other investigations are ordered in suspected PDA
CXR, ECHO
What will be seen on CXR in PDA
- Prominent aortic knob
- Prominent pulmonary. a
What is confirmatory diagnostic test in PDA
ECHO
When is elective surgical PDA closure indicated
- Symptomatic
- Pulmonary HTN
- Non-spontaneous closure
What is used first-line to close PDA in pre-term infants
Indomethacin
What is used to close PDA in infants >5Kg
- Percutaneous catheter occlusion
- Surgical ligation
How is PDA managed if associated with other heart defects
PGE2 given to keep it open then closed surgically later
What is prognosis of PDA
Typically spontaneously closing
What is timeline of PDA
If it has not closed by 2W in term-infants it is unlikely to
What are three complications of PDA
- HF
- Infective endocarditis
- Eisenmenger
What is coarctation of the aorta
Congenital narrowing of the aorta
What are the two forms of coarctation of the aorta
Infant (70%)
Adult (30%)
What % of coarctation occurs during infancy
70%
Where does coarctation often occur
Adjacent to ductus arteriosus
What defect is coarctation associated with
Patent ductus arteriosus
What % of coarctation is in adults
30
What gender is coarctation more common
Males (2:1)
What are 4 associations with coarctation
- Berry aneurysms
- Neurofibromatosis
- Tuner’s Syndrome
- Bicuspid aortic valve
When will symptoms neonatal coarctation present
When the ductus arteriosus closes ~2w
What are the two symptoms of coarctation in neonates
- Heart Failure
- Cyanosis of lower extremities (differential cyanosis)
What is a sign of coarctation in neonates
- Radio-femoral delay.
- Difference in BP between upper and lower extremities.
What are 5 symptoms of coarctation in children
- Cold feet
- Claudication
- Chest pain
- Radio-femoral delay
- HTN in upper extremities. Hypotension in lower extremities
What are 2 signs of coarctation in children
- Ejection systolic murmur over left paravertebral region
- Continous murmur over left sternal edge radiates to between scapula
What are 6 symptoms of coarctation in adults
- HTN
- Epistaxis
- Tinnitus
- Headache
- Claudication
- Radio-femoral delay
Where does coarctation tend to occur in infant disease
Before ductus arteriosus
Explain pathophysiology of coarctation of the aorta
- In coarctation there is narrowing before the ductus arteriosus
- This reduces blood flow through aorta
- Causing back flow of pressure in left ventricle but a low pressure in aorta itself
- This means pressure in the aorta is lower than the pulmonary artery
- So this means deoxygenated blood passes from pulmonary/a to aorta in a right to left shunt and maintains blood flow
- Once the duct closes, less blood can reach distal aorta and rest of the body
- This causes hypo perfusion of organs and multi-organ failure.
- If small segment defect - may be able to be compensated for by collaterals + hence present in childhood
What is first-line investigation for coarctation
BP
What will be seen on BP in coarctation
Difference in BP between upper and lower extremities.
Typically HTN in upper and Hypotension in lower
What is second-line investigation of coarctation
ECHO
What is third-line investigation of coarctation
X-ray
What are 4 findings on CXR in coarctation
- Cardiomegaly
- Increased vascular markings
- Figure of three sign
- Rib notching
What is a figure of three sign
- Dilation pre and post-coarctation causing an hour glass appearance
What is rib notching
Dilation of internal thoracic and intercostal arteries. This increases pressure on inferior ribs causing atrophy - resultant notching.
When is rib notching seen
It is a sign of chronic disease and only seen in children >5Y
How is coarctation managed in neonates
- PGE1 to keep DA open
- Medical management of HF
What is PGE1 called
Alprostadil
How is coarctation managed in older children
Surgical correction
How is coarctation managed in adults
Angioplasty and stending
What is the prognosis of coarctation if untreated
20% would survive past 50y
Give 6 complications of coarctation
- Secondary HTN
- HF
- Aortic dissection
- CAD
- Endocarditis
- Stroke
- MI
What can secondary HTN lead to
Cerebral aneurysms
IC haemorrhage