1. CONGENITAL CARDIAC ABNORMALITIES IN NEONATES
BY: NICOLE STEVENS

2. Heart structure Left and right side of heart separated by a septum
Left and right atriums are collecting chambers for blood, the right side collects from the body and the left from the lungs
The atriums lead into the ventricles, which are the pumping chambers. The left pumps to the body and the right pumps to the lungs.

3. Heart Structure
Valves in the heart ensure the correct directional flow of blood.
Between the right atrium and right ventricle is the tricuspid valve.
Between the left atrium and left ventricle is the mitral valve
Between the right ventricle and the pulmonary artery is the pulmonary valve
Between the left ventricle and the aorta is the aortic valve

4. Embryology Heart develops between the 3rd and 7th weeks of pregnancy.
Heart starts as a hollow tube, as it grows it is forced to bend and rotate – resulting in the formation of all structures
At 8 weeks the heart is functioning and looks like a small adult heart

5. In-utero structures
In utero nutrients and oxygen are provided via the placenta
The lungs are bypassed
The foramen ovale is a hole covered by a flap that allows right to left blood flow from the right atrium to the left atrium (avoiding blood going into the right ventricle and pumping to the lungs).
The ductus arteriosus also allows shunting away from the pulmonary circuit by moving blood from the pulmonary artery across to the aorta.

6. Congenital heart defects
A defect that a baby is born with.
Can effect:
The chambers
The major arteries
The heart valves
Or a combination of these
Congenital defects are caused by a problem in the heart’s development during the first few weeks of pregnancy; exact cause may be unknown, but there are risk factors.

7. Risk Factors Infections (eg German measles)
Certain medications can be teratogenic
Nicotine
Alcohol consumption
Diabetes
Family history (small risk only)
Approx. 1 in 100 babies are born with a heart defect, many defects are minor and can be corrected with medication and/or surgery.

8. Murmurs
Caused by turbulence in the flow of blood through the heart valves
Can be a sign of heart defects
Commonly heard when there are septal defects eg. ASD, VSD
A patent ductus arteriosus will also be heard as a murmur.
Often the louder the murmur the smaller the defect (creates more turbulence)

9. Arrhythmias
Caused by problems in the hearts electrical system, examples:
Bradycardia: beating too slowly
Tachycardia: beating too fast; SVT unresolved will need emergency management to revert (eg with ice, +/- adenosine
Atrial fibrillation: irregular and inefficient beating of the atriums
Long QT syndrome: genetic, can be life threatening

10. Diagnosis Pregnancy ultrasounds Medical history
Physical examination, auscultation
ECG (particularly with arrythmias)
CXR (check size and shape of heart; fluid build up in lungs)
Echocardiogram (heart ultrasound)
Cardiac catheterisation (check pressures, oxygenation in the different chambers; angiography to check flow); also can be used as a treatment option with the balloon angioplasty procedures and insertion of stents.

11. Medications Digoxin: improves contractility
Diuretics: increase urine output
ACE inhibitors: dilation of blood vessels
In neonatal period:
Ibuprofen: PDA closure
Prostaglandin: keep PDA open, in duct dependent disorders
Inotropes: to improve contractility
Sildenafil: dilation of pulmonary vessels
Nitric: PPHN management

12. Duct Dependent CHD
Need flow through PDA to maintain systemic circulation:
Coarctation of the aorta
Critical aortic stenosis
Hypoplastic left heart syndrome
Need flow through PDA to maintain pulmonary circulation:
Pulmonary atresia
Critical pulmonary stenosis
Tricuspid atresia (between right atrium and ventricle)
Tetrology of fallot
Systemic and pulmonary circulations separated:
Transpostion of the great arteries

13. Tetrology of Fallot Effects about 5 out of every 10,000 babies
Involves 4 heart defects: a large VSD, pulmonary stenosis, right ventricular hypertrophy, an overriding aorta (aorta is located between the left and right ventricles, directly over the VSD, thus allowing oxygen poor blood to flow into the aorta/body)
Requires surgery to repair and prolong life

14. Presentation
If undiagnosed antenatally you may be caring for these babies on postnatal ward, or visiting on domicillary:
Difficulty feeding
Increased WOB, increasing cyanosis (largely unresponsive to oxygen therapy)
Tachycardia, tachypnoea
May or may not be a murmur
Collapse, grey appearance, weak or absent peripheral pulses.

15. Assessment Arterial blood gases (preferable from right radial artery
Pre and post ductal saturations
Four limb BP’s
Echocardiogram

16. Management Intubate if necessary
Gain x 2 IV access points (eg double lumen UVC, or 2 peripheral cannulas)
Commence prostaglandin infusion
Bloods (FBE, CRP, Culture, gases)
Fluid management
Antibiotics
Inotropes if required
Transfer to a tertiary facility

17. PROSTAGLANDIN INFUSION
Used to maintain patency of Ductus arteriosus
Side effects include apnoea and hypotension (monitoring and ability to intubate if required essential)
Ensure stable on infusion before transfer
Other side effects: jitteriness, myoclonic jerks, irritability, fever and diarrhoea

18. Ventricular septal defects
Hole between the ventricles
One of the most common CHD’s
Can occur in different locations and be different sizes. The septum is mainly muscle in one section and mainly fibrous thinner material in another. The location and size will determine the consequence.
Untreated, a large VSD can lead to congestive heart failure, as fluid builds up in the lungs
Many small lesions will close of their own accord
Adequate growth is a positive sign that a baby is relatively unaffected by the VSD

19. Atrial Septal Defect Hole between the 2 atriums
Location and size can vary
Presence allows flow from high pressure left atrium to low pressure right atrium; increase risk of pulmonary congestion. Symptoms: failure to thrive, fatigue, shortness of breath
ASD that don’t close and require intervention may be managed with the placement of a patch via a cardiac catheterisation proceduce

20. Reference List www.heartfoundation.org.au