Paediatric Cardiology Flashcards
Describe the fetal circulation
placenta
oxygenated blood enters body via umbilcal vein
bypasses liver via ductus venosus
enters IVC
enters RA
passes into LA via foramen ovale
any blood not in LA continues to RV and pulmonary arteries
ductus arteriosus to aorta to bypass lungs
umbilical arteries from internal iliacs back to placenta
Why do the duuctus venosus, foramen ovale and ductus arteriosus exist?
to conserve oxygen and nutrients for the whole of the body
bypassing liver and lungs
What happens to the ductus venosus at birth?
umbilical cord cut
leads to umbilical vein shutting off
leads to no ductus venosus!
becomes ligamentum venosum
What happens to the foramen ovale at birth?
at birth, air enters the lungs
pulmonary arterioles were vasoconstricted due to hypoxic vasocontriction
at birth, the alveoli become full of oxygen, leading to vasodilation of the arterioles
the previously high pressure pulmonary circulation becomes low pressure
pressure in RV falls to below pressure of LV
this causes the foramen ovale to close in the first few minutes after birth!
becomes fossa ovalis
What happens to the ductus arteriosus at birth?
placenta was releasiign prostaglandin into the fetal circulation, keeping it open
at birth, the increase in o2 and the drop in prostaglandins causes the ductus arteriosus to close within a day
becomes the ligamentum arteriosum within 2 weeks
Describe the effects of patent ductus arteriosus (PDA)
failure to close leads to overloading of the lungs as blood flows from aorta to pulmonary arteries
can lead to pulmonary HTN
What are the effects of pulmonary HTN in PDA
can lead to reversal of blood flow back to aorta as pulmonary P >aorta P. R to L
Eisenmenger’s syndrome!
differential cyanosis - cyanosis in lower extremities
branches to upper extremities and head have left aorta before the PDA
What are the features of PDA
most asymptomatic
continuous machinery murmur
thrill at upper left sternal border
bounding peripheral pulse
Why is there a bounding peripheral pulse in PDA
run off into pulmonary circulation from aorta
leads to wide pulse pressure
causes bounding peripheral pulse
What is the treatment for PDA
surgery to close
How does the atrial septum form?
septum primum grows down. ostium primum forms inferiorly, septum fuses with endocardial cushions. ostium secundum forms superiorly. ostium primum regresses.
septum secundum grows on the right hand side of septum primum. foramen ovale forms in it.
blood passes through the foramen ovale and ostium secundum from RA to LA
What causes an ASD
secundum ASD = septum secundum growth insufficient
primum ASD = ostium primum remains open
sinus venosus defect
coronary sinus defect
What are the features of ASD in a child
asymptomatic!
What are the features of ASD in an adult
SOB palpitations fatigue syncope peripheral oedema arrythmia RHF Eisenmenger's
Why does Eisenmenger’s occur in ASD
L to R shunt overloading of pulmonary circulation pulmonary HTN leads to switch to R to L shunt as RA P > LA P cyanotic
What are the signs on examination in ASD
widely split second heart sound
soft systolic ejection murmur at left sternal border
What is a paradoxical embolism?`
occurs if shunt switches to R to L in ASD
clot from DVT bypasses lungs and can go straight to head causing stroke
What investigations need to be done is ASD
ECG
CXR
echo
What can be seen on an ECG in ASD
tall p wave - due to right atrial enlargement
right axis deviation
AF
What can be seen on a CXR in ASD
cardiomegaly
enlarged RA and RV
increased pulmonary markings
How is ASD managed
diuretics if causign HF
surgical closure - open or transcatheter
What are the complications for women of child bearing age with ASD
increased risk of pre-eclampsia, low birth weight and fetal loss
if pulmonary HTN, significant increases risk of mortality in pregnancy - AVOID!!!
Describe the formation of the ventricular septum
membranous portion grows down from endocardial cushions
muscular portion grows up from base of heart - accounts for majority of septum
How can VSDs be classified
perimembranous defect
muscular defect
subarterial infundibular - adjacent to the arterial valves
Inlet or AV canal - lie beneath the septal leaflet of the tricuspid valve
What conditions are associated with VSD
Down's - trisonomy 21 Patau's - trisonomy 13 Edward's - trisonomy 18 Di george - 22q11 deletion Turner's - 45X diabetes in pregnancy fetal alcohol syndrome
What are the symptoms of VSD
asymptomatic at birth
if moderate to large: excercise intolerance - feeding affected - increased RR, slow feeding, increased effort of breathing. leads to poor weight gain
if very large: pulmonary HTN, leads to R to L shunt. causes Eisenmenger’s cyanosis
What are the signs of VSD
mild: child well developed and pink, harsh systolic murmur at lower left sternal edge
moderate to large: parasternal heave, grade 2-6 systolic murmur at lower left sternal border
State the grading of murmurs
1 - The murmur is only audible on listening carefully for some time.
2 - The murmur is faint but immediately audible on placing the stethoscope on the chest.
3 - A loud murmur readily audible but with no thrill.[4]
4 - A loud murmur with a thrill.
5 - A loud murmur with a thrill. The murmur is so loud that it is audible with only the rim of the stethoscope touching the chest.
6 - A loud murmur with a thrill. The murmur is audible with the stethoscope not touching the chest but lifted just off it.
What investigations should be done in VSD
ECG
CXR
echo
What can be seen on ECG of VSD
LVH,
RAD
RVH and RAH if pulmonary HTN
What can be seen on CXR of VSD
cardiomegaly
What is the manaagement of VSD
30-50% close spontaneously!
moderate to severe: give diuretics, high energy feeds, ACEi to decrease afterload
surgery if HF or poor growth
pulmonary artery banding to protect against pulmonary HTN
What are the long term consequences of VSD
aortic regurgitation
IE
Eisenmenger’s
RBBB
Describe the heart in Tetralogy of fallot
RV outflow obstruction
causes RV hypertrophy
VSD - allows R to L shunt
overriding aorta - RV and LV exit via it
CYANOTIC
What determines the severity of Tetralogy of fallot
the degree of RV outflow obstruction
What conditions are associated with Tetralogy of fallot
22q11 deletion
down’s
fetal alcohol syndrome
CATCH 22
How are most tertalogy of fallot discovered?
antenatal USS
newborn baby check - auscultation
low o2 sats at birth
How would tetralogy of fallot present in an infant
poor feeding breathlessness agitation low birth weight, growth restricted dyspnoea on exertion eg. crying
How would tetralogy of fallot present in an older child on examination
cyanosis
clubbing
RV predominance
systolic thrill over lower left sternal border
systolic ejection murmur - due to pulmonary stenosis
single S2 - no closure of pulmonary valve
What investigations should be done in tetralogy of fallot
ECG -
CXR
echo
What is seen on CXR in tetralogy of fallot
boot shaped heart - due to concavity in the area of main pulmonary artery and enlarged aorta
What is seen on ECG in tetralogy of fallot
RVH, RAD
What is the management of tetralogy of fallot in neonates
immediate o2
prostaglandin E1 - maintains patency of ductus arteriosus
primary repair or two stage repair
What long term complications can occur with tetralogy of fallot
Residual pulmonary incompetence.
Aortic root dilation.
Sustained ventricular tachycardia.
Some children may show delayed neurodevelopment.
Sudden death.
After 5-20 years following surgery, patients generally have reduced exercise capacity and cardiac output compared with that of healthy individuals.
describe transposition of the great arteries (TGA)
the RV empties into the aorta
the LV empties into the pulmonary arteries
therefore there are two circulations in parallel
RV to aorta to IVC and FVC to RV
LV to pulm arteries to pulm veins to LV
CYANOTIC
What increases the risk of TGA
maternal rubella or viral infection
maternal alchohol
>40y
diabetes in pregnancy
What are the types of TGA
TGA with intact ventricular septum
TGA with VSD
TGA with VSD and pulmonary stenosis
What are the symptoms of TGA
with intact septum:
cyanosis, tachypnoea, resp distress, metabolic acidosis within one week
with VSD:
congestive HF leading to tachypnoea, tachycardia, sweating and poor feeding within a few weeks
What are the signs of TGA on auscultation
with intact septum:
single and loud S2, no murmur
with VSD:
systolic murmur, greater pulmonary resistance leads to decrease in intensity
Give some differentials for TGA
infection IRDS meconium aspiration pneumothorax fallot's pulmonary atresia
What investigations can be done in TGA
pulse oximetry
EG
CXR
echo
What is seen on CXR in TGA
increased pulmonary vascular markings
‘egg on a string’ - due to heart being slightly enlarged and appears like an egg lying on its side, narrow vascular pedicle because aorta and pulmonary artery lie one in front of the other
What is the management of TGA
immediate: IV prostaglandin E1 infusion to maintain patency ductus arteriosus, oxygen
urgent atrial septostomy - ceates/maintians ASD to increase mixing of pulmonary and systemic circulations
arterial switch operation (ASO) within a few days - most done at day 3 of life
What are some of the long term complications of TGA
Neopulmonary stenosis Neoaortic regurgitation Neoaortic root dilatation Coronary artery disease Obstructed coronary arteries leading to myocardial ischaemia, infarction and death sudden cardiac death neurodevelopmental abnormalities
What are the predictors of poor developmental outcome in a child with TGA
Low gestational age
high pre-operative lactate
What is coarctation of the aorta?
narrowing of the aorta, most commonly just distal to the origin of the left subvlavian artery.
close to ligamentum arteriosum/ductus arteriosus
(most commonly before PDA in neonates)
Which genetic condition is coarctation of the aorta common in
turner’s syndrome
How does coarctation of the aorta present in neonates
can be seen in neonatal USS
poor feeding lethargy tachypnoea congestive cardiac failure shock
delayed pulse in lower limbs differential cyanosis (PDA open, R to L shunt as low pressure in aorta distal to coarctation) murmur
How does coarctation of the aorta present in adults
most asymptomatic!
picked up incidentally as high BP or murmur
can cause:
headache, nosebleeds
;eg cramps, lower limb weakness, cold feet, neruological problems
delayed and diminished pulses in lower limbs distal to lesion (radio-femoral delay)
higher BP in arms than legs
systolic or continous murmur best heard under left scapula or in left infracalvicular area
What does coarctation increase your risk of?
berry aneurysms leading to SAH - increased in pregnancy
aortic dilation
aortic dissecton - high risk in pregnancy.
Infective endocarditis.
What are some differentials for coarctation of the aorta
hypoplastic left heart
septal defect
AS
cardiomyopathy
What investigations need to be done in suspected coarctation of aorta
if HTN - U+E, FBC, glucose
if shock - ABG, FBC, U+E, glucose, clotting, cultures
CXR echo MRI ECG cardiac catheterisation
What can be seen on CXR in coarctation of aorta
the coarctation itself!
notching of ribs 3-9 (due to dilation of posterior intercostal arteries - increased flow die to high P pushing blood from anterior intercostal arteries)
How is coarctation of the aorta managed
neoneates - prostin to keep DA open diuretics and inotropes in congestive cardiac failire beta blocker if HTN surgery! - balloon angioplasty and stenting - open heart
What are the features of an innocent murmur?
Soft • Systolic • S1 and S2 normal • Symptomless • Standing/sitting position vary • Special tests (ECG, CXR) normal
