Congenital Heart Disease Flashcards
What is congenital heart disease?
Abnormality of the heart structure that is present at birth (inherited/genetic disease tend not to come under this)
Also, it is a gross structural abnormality of the heart or intrathoracic great vessels that is actually or potentially of functional significance
3 examples of congenital heart disease?
Ventricular-septal defect (VSD)
Patent Dustus Arteriosus (PDA)
Atrio-ventricular septal defect (AVSD)
How does congenital heart disease present?
During screening (antenatal scan or newborn baby check)
Well baby with clinical signs
Unwell baby - cyanosis, shock, cardiac failure
Look carefully at babies with other congenital/genetic abnormalities, e.g: Down’s syndrome (40-50% have a congenital heart disease)
When does congenital heart disease present and with what symptoms at these times?
Antenatally
Soon after birth - cyanosis
Day 1-2 baby check - murmurs, abnormal pulses, cyanosis
Days 3-7 - sudden circulatory collapse, shock, cyanosis, sudden death
4-6 weeks - sign of cardiac failure (reduced feeding, failure to thrive, breathlessness, sweatiness)
6-8 week GP check - incidental finding of murmurs at other clinical contacts
Why is the first week particularly important?
Around days 3-7, the ductus arteriosus closes and, if the baby has circulation dependent on its patency, it is potentially fatal
What does antenatal screening involve?
Ultrasound at 18-22 weeks gestation allows a 4-chamber heart view and outflow tract view
Disadvantages of antenatal screening?
Sensitivity is very variable and dependent on:
Operate experience and training
Maternal characteristics, e.g: fat tissue, etc
Need for expert follow-up/detailed foetal echocardiography and counselling
Advantages of antenatal screening?
Outcomes probably better for major disease if it is antenatally detected:
Avoid cardiovascular collapse, undiagnosed death, etc
Minimise hypoxia
Improve condition at time of going to surgery
What does newborn screening involve?
Clinical examination at around 24 hrs of age, inc. checking femoral pulses, heart sounds and presence of murmurs
In some regions, inc. measurement of pre and post-ductal saturation (right hand for pre-ductal and either foot for post-ductal)
What do pre and post-ductal saturations indicate?
Low sats overall could imply cardiac or respiratory disease
Difference of 3% or more between pre and post-ductal implies right to left shunt at ductus
Effectiveness of newborn screening?
More than half the infants with congenital heart disease are missed by this; around 1/3 of infants with life-threatening heart abnormalities leave hospital undiagnosed
Murmurs are common in normal babies, due to remaining pressure differences and closure of the ductus arteriosus
Causes of cyanotic heart disease?
Any condition causing deoxygenated blood to bypass lungs and enter the systemic circulation, e.g: PPHN
Any condition where mixed oxygenated and deoxygenated blood enters the systemic circulation from the heart, e.g: PDA
Cyanotic appearance?
Bluish discolouration; if in doubt, measure stats
Symptoms of cardiac disease causing cyanosis?
Tend to be blue with little/no respiratory distress; may have pre-post ductal differential
Symptoms of respiratory disease causing cyanosis?
Associated with increased work of breathing and X-ray changes
Symptoms of PPHN causing cyanosis?
Often seen in otherwise very unwell babies; typical to have a LARGE pre-post ductal differential
What is transposition of the great arteries?
Essentially, aorta and pulmonary artery swap positions; so, aorta is the ouflow for the right ventricle and pulmonary artery is the outflow for the left ventricle
Blood in the aorta goes to left side of the heart without being deoxygenated
Treatment of transposition of the great arteries?
Key to survival: PFO (Patent Foramen Ovale)
Via umbilical vein, a catheter is inserted into the IVC, into the right atrium and through the foramen ovale; a balloon is inflated and pulled through to make the foramen larger and allow more blood shunting
This is done to allow time until arterial switch surgery can be done (swap aorta and pulmonary artery)
What are duct-dependent lesions?
Any condition in which the pulmonary or systemic circulation is dependent on the patency of the ductus arteriosus (PDA)e.g: any condition where there is reduced blood flow from left heart
If not detected earlier, babies present with circulatory collapse when the duct closes
Presentation of baby with duct-dependent lesion?
3-5 day old infant suddenly pale, tachypnoeic and distressed and rapidly become more unwell
Clinical signs inc. pallor, prolonged CRT, poor/absent pulses, hepatomegaly, crepitations and increased work of breathing
Profoundly acidotic
Differential - inc. sepsis, metabolic conditions
Treatment for duct-dependent lesions?
Diagnosis before baby becomes unwell is desirable in duct-dependent conditions
ABC - support airway and breathing as necessary
Commence low-dose PGE2 immediately to maintain duct patency
Multi-system supportive treatment
Watch for apnoea (side effect of PGE2) but avoid intubation and ventilation if possible
Move to cardiac surgical centre
Two types of duct-dependent conditions?
Duct-dependent systemic circulation, e.g: hypoplastic left heart, critical aortic stenosis, interrupted aortic arch, critical coarctation of the aorta
Duct-dependent pulmonary circulation, e.g: tricuspid atresia, pulmonary atresia
What is interruption of the aortic arch?
Aortic arch ends prematurely
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What is pulmonary atresia?
Pulmonary valve orifice fails to develop, preventing outflow from right ventricles
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