Paediatric Cardiology - Embryology and Acyanotic Heart Defects Flashcards
What are the five embryological origins of the heart?
Truncus arteriosus Bulbus cordis Ventricle Atrium Sinus venosus
What does the truncus arteriosus form?
Aorta and Pulmonary trunk
What does the bulbis cordis form?
Ventricles - smooth part (with primitive ventricle)
What does the primitive ventricle become?
Ventricles - trabecular part of wall (with bulbis cordis)
What does sinus venosus become?
Smooth part of atria
SA Node
Coronary sinus
What shunts are present in the foetus?
Ductus arteriosus
Foramen vale
Ductus venosus
What is the function of ductus arteriosus and what does it become?
Bypass lungs to protect them
Ligamentum arteriosum
What is the function of foramen ovale and what does it become?
Bypass lungs to protect them
Fossa ovalis
What is the function of ductus venosus and what does it become?
Bypass liver as it is very metabolically active
Ligamentum venosum
How does ductus arteriosus shut?
When the baby takes its first breath, the ductus arteriosus contracts due to high O2 sats
How does foramen ovale shut?
The first breath opens the pulmonary circulation causing LA pressure > RA pressure which pushes the septum shut
How does ductus venosus shut?
When placental support is removed
What are the acyanotic heart defects?
Left to Right shunts
ASD VSD Coarctation of the Aorta Patent Ductus Arteriosus Pulmonary stenosis
How do acyanotic defects present?
Most are picked up on antenatal screening
Asymptomatic mostly
Possibly
Fail to thrive
Resp infections
Heart failure
Why can you see heart failure with acyanotic heart defects?
Increased pressure in pulmonary circulation
What is Eisenmenger’s syndrome?
L –> R shunt swap to R –> L if pulmonary pressure rise to exceed systemic pressure
How are acyanotic heart defects commonly investigated?
Echo - flow and anatomy
ECG - identity cardiomegaly or pulmonary hypertension
Cardiac catheter - if severe
How would you see cardiomegaly or pulmonary hypertension on ECG?
Commonly Left Ventricular hypertrophy - lead I increase, lead III invert
Right ventricular hypertrophy, right axis deviation, p pulmonale, tall R in V1, right ventricular strain
How are acyanotic heart defects managed in the general term?
Loop diuretics if heart failure
Surgical closure of defect
What are the risk factors for developing an acyanotic heart defect?
Family history
Maternal smoking/toxins/infection/diabetes
Genetic conditions - Down’s
What are the types of Atrial Septal Defect?
Ostium primum ASD
Ostium secundum ASD
What is a patent foramen ovale?
Isolated defect in the ostium secundum (more common)
What does a ostium primum Atrial Septal Defect leave?
Left to right shunt
+
Tricuspid incompetence
Seen in downs
What murmur would you hear with an Atrial Septal Defect?
Ejection systolic
Best heard at left sternal edge - increased blood flow in right ventricular outflow
What clinical features can be suggest a patent foramen ovale?
Abnormal right ventricular pressure
Widely split and fixed second sound
Tricuspid flow murmur - mid diastolic rumble
Pulmonary flow murmur - ejection systolic
What investigations are used to diagnose an Atrial Septal Defect?
CXR - pulmonary plethora
ECG - right ventricular hypertrophy
Echo
How are Atrial Septal Defect’s managed?
Surgical - transcatheter closure
What is the most common type of congenital heart defect?
VSD
How common are Ventricular Septal Defect’s?
Seen in 1/3 of children with heart defects
2-6 per 1000 births
What happens to 50% of Ventricular Septal Defect’s?
Close spontaneously
What is the prognosis of a Ventricular Septal Defect dependent on?
Size and position of defect
Development of changes due to blood shunting - pulmonary hypertension/narrowing of pulmonary arteries reduce left to right shunt
What chromosomal disorders are Ventricular Septal Defect’s associated with?
Down’s
Edward’s
Patau
What examination features can be seen with a Ventricular Septal Defect?
Harsh pan systolic murmur at left lower sternal border
Heard louder in smaller defects
Parasternal thrill
What does a Ventricular Septal Defect cause?
Pulmonary congestion - more blood through pulmonary circulation
High output cardiac failure - increased blood return from pulmonary circulation
What is a small Ventricular Septal Defect called and what is it its prognosis?
Maladie de Roger
Spontaneous closure
What is warranted if a small Ventricular Septal Defect doesn’t close within 12 months?
Echo to look for complications
How does a medium Ventricular Septal Defect present?
Infancy symptoms:
Weight gain
Difficulty feeding
Recurrent chest infections
What can be heard if pulmonary blood flow is affected by a Ventricular Septal Defect?
Mid diastolic murmur
What investigations are done for a mid sized Ventricular Septal Defect and what will they show?
CXR - moderate cardiac enlargement
Echo - position of defect
Doppler - shunt
What are the complications of a Ventricular Septal Defect?
Aortic regurgitation Infective endocarditis Eisenmenger's syndrome Right heart failure Pulmonary hypertension
Why can you get aortic regurgitation with a Ventricular Septal Defect?
Poorly supported right coronary cusp lead to cusp prolapse
How is heart failure treated if present?
Diuretics
ACE-Inhibitor
What is the management plan for a mid sized Ventricular Septal Defect?
Spontaneous improvement in most
Can do surgical correction - case by case
What is more likely to develop in a large Ventricular Septal Defect?
Heart failure develops early
What is the management plan for a large Ventricular Septal Defect?
Treat heart failure
Surgical closure under cardiopulmonary bypass
Banding of pulmonary artery in young infants for temporary respite until definitive surgery
What is coarctation of the aorta?
Narrowing of the aorta
Where can coarctation of the aorta occur?
Preductal or post ductal (ductus arteriosus)
98% at level of ductus arteriosus
Who does coarctation of the aorta affect?
Males 2:1 Females
If preductal - symptomatic infants
If post ductal - asymptomatic children
How do preductal coarctations normally get picked up?
Antenatal diagnosis due to abnormal circulation
Sick neonate with absent femoral pulses - MUST CHECK FEMORAL PULSE WHEN EXAMINING NEONATES
What happens in a preductal coarctation?
When ductus arteriosus is open, right ventricle adequately maintain CO
When it closes heart failure occurs
How is preductal coarctation of the aorta managed?
Prostaglandin infusion to maintain ductal patency
Transfer to cardiac centre for surgical intervention
How do post ductal coarctations present?
Asymptomatic usually
Possible leg pains or headache
Hypertension
BP difference in arms and leg
May have ejection click murmur due to biscupid aortic valve
Systolic ejection murmur in left inter scapular area
How can coarctation of the aorta be managed surgically?
Catheter balloon dilatation
Resection of coarcted segment with end to end anastomosis
What is patent ductus arteriosus?
Failure of the ductus arteriosus to close following birth
How common is a Patent Ductus Arteriosus?
Very common in pre-term children
When does the ductus arteriosus close? (functionally and anatomically)
Functionally - 12-18 hours
Anatomically - 2-3 weeks
What are the risk factors for Patent Ductus Arteriosus?
Preterm
Down’s syndrome
High altitudes
What clinical features are seen in a Patent Ductus Arteriosus?
Bounding pulses - wide pulse pressure
Systolic machinery type murmur at left sternal edge radiating to the back
How is a Patent Ductus Arteriosus diagnosed?
CXR can show increased pulmonary markings
ECG - left ventricular hypertrophy, prolong PR
How else can a Patent Ductus Arteriosus be visualised?
Echo
Doppler - shunt
How is a Patent Ductus Arteriosus managed?
Surgical closure - ligation, division or transvenous umbrella occlusion
Pharmacological closure - indomethacin (not for term infants)
Why are Patent Ductus Arteriosus’s closed?
Much higher risk of infective endocarditis or pulmonary vascular disease
