Cardio

Question 1

Describe the foetal circulation.

Answer 1

• oxygenated bloods from placenta is carried via umbilical vein into IVC
• oxygenated blood arrives at RA and flows through foramen ovale into LA then to LV –> aorta and body
• portion of blood makes it to RV and is pumped to pulmonary artery which moves to aorta via ductus arteriosus (high pressure in collapsed lung)

Question 2

what could go wrong to cause congenital heart defects?

Answer 2

• Genes like trisomy 21, cardiomyopathy genes
• Environment factors such as teratogens like alcohol, smoking, warfarin and lithium
• Maternal disorders like rubella
• Maternal diabetes

Question 3

what are the foetal shunts available?

Answer 3

• Foramen ovale : from foetally higher pressure RA to LA via atrial septum with intention of bypassing the lungs
• Ductus arteriosus : shunt from pulmonary artery into aorta to bypass lungs in systole
• Ductus venosus : umbilical vein into IVC (bypassing liver?)

Question 4

what cause the foetal shunts to close?

Answer 4

• with initial breaths and increase in volume of blood to lungs and resistance in pulmonary circulation the LA pressure rises
• RA pressure falls due to exclusion of placental circulation and this change in pressure causes foramen ovale flap to shut - septum primum against septum secundum
• ductus arteriosus closes within first few hours to days

Question 5

what might be the initial presentation of a congenital heart defect?

Answer 5

• antenatal cardiac USS detects 50-60%
• cyanosis at birth
• detection of murmur
• HF
• shock when foramen ovale shuts causing obstruction

Question 6

how do you differentiate between an innocent murmur and a pathological one?

Answer 6

• aSymptomatic
• Soft blowing murmur
• Systolic murmur only
• left Sternal edge

Question 7

how does HF present in a baby?

Answer 7

• breathlessness
• sweating
• poor feeding
• recurrent chest infections
• poor weight gain, tachypnoea, tachycardia, murmur etc

Question 7

what are some examples of acyanotic heart defects?

Answer 7

• VSD
• ASD
• PDA
• coarctation of aorta
• aortic valve stenosis

Question 8

what are some classic features of an acyanotic heart lesion?

Answer 8

• L -> R shunting with mixing
• increased pulmonary blood flow risking pulmonary HTN and Eisenmenger
• lesions above nipple ejection systolic murmur
• lesions below nipple pan systolic murmur

Question 9

What are some examples of cyanotic congenital heart disease?

Answer 9

• TOF
• TGA
• tricuspid atresia

Question 10

what is an ASD?

Answer 10

left to right shunt from LA into RA down pressure gradient
- acyanotic
- may lead to right sided strain and Eisenmenger
- types: ostium secondum, primum and patent foramen ovale

Question 11

what might you find on examination for ASD?

Answer 11

• Ejection systolic murmur heard loudest at the upper-left sternal border
• Widely fixed splitting of the second heart sound

Question 12

how might ASD present?

Answer 12

*asymptomatic, recurrent infections
- may present at 4-5y
- 40+ with arrhythmias and dyspnoea

Question 13

how might you investigate acyanotic congenital heart defects?

Answer 13

• pulse oximetry
• Echo
• CXR: cardiomegaly and pulmonary oedema?
• ECG: may show hypertrophy

Question 14

how is an ASD managed?

Answer 14

• 7-8mm may spontaneously close so w&w
• large defects require percutaneous catheter closure via femoral vein
• tx at about 3-5y to prevent RHF and arrhythmias

Question 15

what is a VSD?

Answer 15

VSD means left to right shunt from LV into RV down pressure gradient through a defect in septum
*most common CHD
*associated with Down’s and Turner’s

Question 16

how might VSD present?

Answer 16

Small – may be asymptomatic, normal growth
Moderate – poor feeding, failure to thrive (FTT), short of breath (SOB)
Large – poor feeding, FTT (falls below centiles), SOB, sweaty and pale with feeds

Question 17

what might you find on examination for VSD?

Answer 17

Pan-systolic murmur heard loudest at the lower left sternal border (LLSB)
- may palpate systolic thrill
- loud P2 shows pulmonary HTN

Question 18

how is VSD managed?

Answer 18

• <5mm may close spontanously
• moderate: diuretic therapy with (furosemide+spironolactone) and high caloric feeds (infantrini)
• large: moderate mx, optimise weight gain, surgery before 12m to present PPHN –> transvenous catheter closure

Question 19

how might a PDA present on examination?

Answer 19

Symptoms usually present 3-5 days after birth when the duct begins to close
- bounding pulses and wide pulse pressure
- continuous machinery murmur at upper-left sternal border and thrill

Question 20

how is PDA managed?

Answer 20

• preterm may close spontaneously
• medical: indomethacin, ibuprofen to neonate
• surgical: catheter closure or PDA ligation when weight 5kg

Question 21

why might it be not so wise to close a PDA in certain situations?

Answer 21

if associated with another heart defect amenable to surgery then prostaglandin E1 given to keep duct open until after repair - alprostadil

*to prevent obstruction

Question 22

what are the 4 abnormalities found in a patient with a TOF?

Answer 22

• large VSD
• pulmonary stenosis
• hypertrophy of RV
• overriding aorta (over VSD not LV)

Question 23

what are some RF for TOF?

Answer 23

Males
1degree family history of CHD
Teratogens like Alcohol (fetal alcohol syndrome)
Warfarin (fetal warfarin syndrome)
Trimethadione
genetics

Question 24

when would TOF present?

Answer 24

mild: asymptomatic, continues to progress to cyanosis moderate: first few weeks (post PDA closure), prone to recurrent chest infections, failure to thrive extreme: may have pulmonary atresia, hence PDA dependent

Question 25

How would TOF present?

Answer 25

- cyanotic spells due to RV outflow tract obstruction - murmur caused by pulmonary stenosis: crescendo-decrescendo with harsh ejection systolic over L sternal edge - cyanosis, poor feeding, sweating during feeds - tet spells: neonate going blue when feeding - CHF signs

Question 26

how might you investigate TOF?

Answer 26

ECG: RVH, R axis deviation bloods for genetic syndromes CXR: boot shaped heart for RVH, reduced lung markings ECHO: gold standard cardiac catheter? delineate lesion

Question 27

How is TOF managed?

Answer 27

- severe cyanosis: prostaglandin infusion to maintain patency of PDA until correction - tet spells management - HF: digoxin, loop diuretics - endocarditis prophylaxis - surgical: Blalock-Taussig shunt to mimic PDA, *lifelong followup with exercise tolerance, ECG etc

Question 28

how are tet spells managed?

Answer 28

*Knee to chest position to increase systemic vascular resistance and promote blood flow into the pulmonary circulation Oxygen Morphine B-blockers

Question 29

what is transposition of the great arteries?

Answer 29

aorta arises from the RV and pulmonary artery from the LV, resulting in deoxygenated blood from the RV being circulated around the body RF: diabetic mothers

Question 29

how does TGA present?

Answer 29

*when PDA closes at day 3-5 - signs of CCF like tachypnoea, tachycardia, failure to gain weight - cyanosis - poor feeding - murmur: systolic murmur if VSD, loud single S2

Question 30

How is TGA managed?

Answer 30

- emergency: prostaglandin infusion, correct metabolic acidosis, atrial balloon septostomy - definitive: atrial switch by age 4w *pregnancy complications for patients later

Question 31

how does aortic stenosis present?

Answer 31

*born with narrow aortic valve which restricts blood from LV into aorta - ejection systolic murmur loudest in aortic area, crescendo-decrescendo radiating to carotids - slow rising pulse and narrow pulse pressure

Question 32

how is aortic stenosis managed?

Answer 32

- precutaneous balloon aortic valvoplasty - surgical aortic valvotomy - valve replacement

Question 33

what is pulmonary stenosis and what is it associated with?

Answer 33

usually consists of 3 leaflets that open and close and let blood out into pulmonary artery and prevent back flow into RV when leaflets abnormally fuse or thicken there is a narrowing between the RV and PA causing a restricted exit of blood - associated with TOF, Williams syndrome, Noonan syndrome and congenital rubella

Question 34

how might pulmonary stenosis present?

Answer 34

- ejection systolic murmur loudest at pulmonary area - palpable thrill over pulmonary area - RV heave due to RVH - raised JVP

Question 35

how is pulmonary stenosis managed?

Answer 35

- mild may not require intervention hence watch and wait - symptomatic or significantly stenosed - balloon valvuloplasty via venous catheter

Question 36

what is hypoplastic left heart?

Answer 36

- abnormal development of left sided cardiac structures which results in obstruction to blood flow from LV - mitral valve, left ventricle, aortic valve, the ascending aorta, and aortic arch - survival depends on two key factors - patent ductus arteriosus - non-restrictive atrial septal defect to ensure adequate mixing

Question 37

how does a hypoplastic left heart present?

Answer 37

- initially healthy until duct closes - with PDA closing systemic perfusion decreases - hypoxaemia, acidosis, shock - cardiogenic shock if duct restricted from birth - due to ischaemia to myocardium

Question 38

how is hypoplastic left heart managed?

Answer 38

- initial - prostaglandin infusion, diuretics, intubation and ventilation, urgent balloon atrial septostomy to ensure mixing - definitive - surgical - norwood procedure, glenn, fontan

Question 39

what is coarctation of the aorta?

Answer 39

congenital narrowing narrowing of aortic arch, usually around the ductus arteriosus *when duct closes aorta also constricts causing obstruction to LV outflow *associated with Turner's

Question 40

how might you detect coarctation of aorta?

Answer 40

- weak femoral pulses : four limb blood pressure to reveal high BP in limbs supplied from arteries that come before narrowing and lower BP after - ejection systolic murmur - grey floppy baby - underdeveloped L arm?

Question 41

how is coarctation managed?

Answer 41

- mild may be symptom free until adulthood without requiring surgical input - urgent - prostaglandin E to keep DA open while waiting for surgery, allows some flow into systemic distal to co-arctation - surgery - correct narrowing and ligate DA