Download Congenital Cardiac Abnormalities - Nicole Stevens

CONGENITAL CARDIAC
ABNORMALITIES IN
NEONATES
BY: NICOLE STEVENS
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.
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
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
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.
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.

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.

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)
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
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.
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

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
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
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.
Assessment




Arterial blood gases (preferable from right
radial artery
Pre and post ductal saturations
Four limb BP’s
Echocardiogram
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
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
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
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
Reference List





www.heartfoundation.org.au
www.neonatal.org.uk/documents
www.nhibi.nih.gov
www.cincinnatichildrens.org
www.childrenscolorado.org