Paeds - cardio Flashcards
what can cause a congenital left to right shunt?
how would they present?
ventricular septal defect
persistent arterial duct
atrial septal defect
they present as breathless
what can cause right to lefts shunts?
how would they present?
tetralogy of Fallot
transposition of the great arteries
they would present as blue
what are the circulatory changes at birth?
first breath = a fall in resistance to pulmonary blood flow
- -> blood flow through the lungs increases six fold
- ->this results in a rise in left atrial pressure.
- -> mean while the blood returning to right atrium falls as the placenta is excluded from the circulation
- -> the changes in the pressure difference causes the foramen ovale to close
- the DA will normally close within the first few hours or days of life
what are the symptoms and signs of heart failure?
symptoms - breathlessness (particularly on feeding or exertion), sweating, poor feeding, recurrent chest infection
signs: poor weight gain or faltering growth, tachypnoea, tachycardia, heart murmur, gallop rhythm, enlarged heart, hepatomegaly, cold peripheries.
what usually causes heart failure in the first week of life?
left heart obstruction e.g. coarctation of the aorta
*if obstruction is very severe then arterial perfusion may be predominantly by right to left flow of the blood via the ductus arteriosus (duct dependant circulation) - closure of the duct = severe acidosis, collapse and death unless duct patency is restored
after the first week of life what is the most common cause of progressive heart failure?
left to right shunt
this eventually causes pulmonary oedema and breathlessness due to decreased pulmonary vascular resistance
what happens if a left to right shunt is left untreated?
children will develop Eisenmenger syndrome which is irreversibly raised pulmonary vascular resistance resulting from chronically raised pulmonary arterial pressure and flow. this lead the shunt reversing to a right to left shunt and results in a blue child. If this develops the only surgical option is a heart-lung transplant if available.
what might cyanosis in the new-born infant in the new born be due to?
- cardiac disorders - cyanotic congenital heart disease
- resp disorders - surfactant deficiency, meconium aspiration, pulmonary hypoplasia
- persistent pulmonary hypertension of the new born - failure of the pulmonary vascular resistance to fall after birth
- infection - septicaemia from group B streptococcus and other organisms
- metabolic disease - metabolic acidosis and shock
what are the different types of ASD?
secundum ASD
partial/primum ASD
what are the symptoms of ASD?
often asymptomatic
may have recurrent chest infections
from the fourth decade they may develop arrhythmias
what are the signs of ASD?
an ejection systolic murmur best heard at the upper left sternal edge - due to increased flow across the pulmonary valve because of the left-to-right shunt
a fixed and widely split second heart sound
what investigations would you perform for ASD?
CXR - cardiomegaly, enlarged pulmonary arteries and increased pulmonary vascular markings
ECG - right bundle branch block
Echo
how do you manage ASD?
if the defect is large enough to cause ventricular dilation treatment will be required.
For secundum ASD this is by cardiac catheterisation with insertion of an occlusive devise
Partial AVSD - surgical correction is needed - usually at about 3-5 years of age to prevent heart failure and arrhythmias
what is a small VSD?
smaller than the aortic valve in diameter - up to 3mm
how would a small VSD present ?
what would you hear when auscultating a small VSD?
what investigations would you perform and how would you manage one?
often asymptomatic
a loud pan-systolic murmur at lower left sternal edge (loud murmur = smaller defect)
quiet pulmonary second sound
CXR and ECG will be normal
echo will demonstrate precise anatomy of defect
management - often will close spontaneously
what is a large VSD?
how would a large VSD present ?
what would you hear when auscultating a large VSD?
what investigations would you perform and how would you manage one?
- bigger than the size of the aortic valve
- symptoms of heart failure with breathlessness and FTT after 1 week old, recurrent chest infections, tachypnoea, tachycardia and enlarged liver from heart failure, active precordium.
- there may be a soft or no murmur = large defect
- there will be a loud pulmonary second sound from raised pulmonary pressure
- CXR - cardiomegaly, enlarged pulmonary arteries, increased pulmonary vascular markings, pulmonary oedema
- ECG - biventricular hypertrophy by 2 months of age
- ECHO - demonstrated anatomy of defect
- Management: diuretic for heart failure (furosemide) often combined with captopril.
Surgery should be performed at age 3-6 month
what is patent ductus arteriosus?
a form of congenital heart defect
generally classed as ‘acyanotic’. However, uncorrected can eventually result in late cyanosis in the lower extremities, termed differential cynaosis.
connection between the pulmonary trunk and descending aorta
usually the ductus arteriosus closes with the first breaths due to increased pulmonary flow which enhances prostaglandins clearance
more common in premature babies, born at high altitude or maternal rubella infection in the first trimester
what are the signs of patent ductus arteriosus?
left subclavicular thrill continuous 'machinery' murmur large volume, bounding, collapsing pulse wide pulse pressure heaving apex beat
how do you manage a PDA?`
1st line - IV indomethacin (inhibits prostaglandin synthesis ) - closes the duct in the majority of the cases
*if it is associated with another congenital heart defect amenable to surgery then prostaglandin E1 is usefull to keep the duct open until after surgical repair
use a percutaneous catheter device closure
if baby too small or large duct then use surgical ligation
what test can be used in cyanosed infants to test for heart disease?
the hypoxia (nitrogen washout) test place them in 100% oxygen for 10 mins and then if right radial artery PaO2 from blood gas remains low then it Is cyanotic congenital heart disease
what are the 4 cardinal anatomical features of tetralogy of Fallot?
ventricular septal defect (VSD)
- right ventricular hypertrophy
- right ventricular outflow tract obstruction
- pulmonary stenosis
- overriding aorta
what are the symptoms of TOF?
cyanosis - hypercyanotic episodes
a loud harsh ejection systolic murmur
in older children there may be clubbing
may have tachypnoea
what investigations would you perform for TOF and what would they show?
CXR - boot shaped heart
ECG - will show right ventricular hypertrophy when older
ECHO - will show the cardinal features.
how do you manage TOF?
complete surgical repair to close VSD and relieve RV outflow obstruction
what is transposition of the great arteries?
the aorta is connected to the right ventricle and the pulmonary arteries are connected to the left ventricle - this means there is two parallel circulation
*incompatible with life unless there is a mixing of blood - often there is naturally occurring VSD, ASD, PDA which can achieve mixing short term
leads to right to left shunt
what are the symptoms of transposition of the great arteries?
neonatal cyanosis
usually appears on day 2 when ductal closure leads to reduced mixing of desaturated and saturated blood
often a loud, single heart sound
how do you manage transposition of the great arteries?
maintain ductus arteriosus with prostaglandin infusion
a balloon atrial septostomy
all patients will require surgery, arteria switch procedure in the neonatal period
