Ministry of Health
See also the S.T.A.B.L.E. Cardiac Module Program
(via the intranet only)
Tetralogy of Fallot
Tetralogy of Fallot is a structural cardiac lesion consisting of
- a conal ventricular septal
- right ventricular
(subpulmonary) outflow tract obstruction
- an aorta which overrides
the VSD, and
- right ventricular
Tetralogy usually presents
with cyanosis, the degree of which is dependent on the degree of RVOT
obstruction and therefore right-to-left shunting. In severe cases
of pulmonary stenosis or pulmonary atresia, pulmonary blood flow may be
Radiologically, the heart
size is usually normal. There is elevation of the cardiac apex,
secondary to right-ventricular hypertrophy. The cardiac silhouette is
often described as "boot-shaped". The lung fields are usually
clear and in cases of severe outflow tract obstruction may appear
oligaemic. There may be a concavity of the left border of the
heart usually occupied by the pulmonary artery.
The radiological appearances can
vary depending on other associated cardiac lesions. For example, if
collateral vessels are present between the aorta and pulmonary circulations,
there may be pulmonary plethora.
Transposition of the Great Arteries
Transposition of the Great Arteries (TGA) is the most common cyanotic
congenital cardiac condition to present in the immediate neonatal period,
particularly if no ventricular septal defect (VSD) is present and there is
poor mixing of blood at the atrial level. Infants can present in shock
and severely acidotic. Clinically, the babies will appear cyanosed. No
murmur is present, unless there is a VSD or some other structural cardiac
Radiologically, the lungs
appear to have increased blood flow and increased pulmonary vascular
markings. The mediastinum is narrow, as the great arteries are
running parallel. Diagnosis is made by echocardiography -
important features to note are the size of the ductus arteriosus,
whether there is a VSD, and how much atrial mixing there is.
Infants with a large VSD or
large atrial communication may present later, within the first 2 weeks,
with cyanosis. Cardiac failure may be present in the presence of a
In the short-term, a
should be commenced to ensure ductal patency. A balloon artial
septostomy is usually performed within the first day or two of life to
assist with mixing at an atrial level. An arterial switch procedure is
usually performed within the first week.
Pulmonary atresia is a condition where the pulmonary valve does not form
properly and there is no flow from the right ventricle into the pulmonary
circulation. This is a lesion which is duct dependent for adequate
pulmonary blood flow. If the ventricular septum is intact, then there
can be early severe cyanosis on the first day. If a VSD is present,
the presentation may be later. The right ventricle is often
hypoplastic. The degree of atrial communication, allowing systemic
blood return to the right atrium and thence the left atrium, is important.
The chest radiograph will show oligaemic lung fields. The cardiac
silhouette may be normal size, or enlarged (in the case shown to the left,
this was from right atrial enlargement due to poor communication between
right and left atria via a restricted foramen ovale). Fistulae from the
right ventricle to the coronary circulation may be present, particularly if
the right ventricle and tricuspid valve are small.
In the short-term, a
should be commenced to ensure ductal patency. A balloon atrial septostomy
may need to be performed within the first day or two of life to assist with
return of systemic venous blood into the systemic circulation. Definite
treatment is dependent on the lesions present and whether a reasonable RV
outflow can be created.
Patent Ductus Arteriosus
Patent ductus arteriosus (PDA) is common in the very preterm infant with
significant lung disease. Radiological signs are non-specific.
However, if the PDA is large
with a significant left-to-right shunt, the lung fields will become
generally hazy and the heart enlarges. This may or may not be in
association with evolving CLD.
The top image to the left
shows a baby with a large duct. The heart is generous and the lung
fields are non-specifically hazy. The baby also has significant
neonatal Chronic Lung Disease.
The second image shows cardiomegaly and some pulmonary plethora in a 4-week
old baby with a large duct which had not closed with two courses of
treatment with Indomethacin.
For echocardiography images of the ductus,
Dextrocardia with situs
Dextrocardia with situs
Dextrocardia is a description term indicating that the heart is in the right
hemithorax. Dextrocardia may be because a normally left-sided heart
(levocardia) is displaced to the right side (either because of pressure from
a mass in the left hemithorax, or collapse of the right lung drawing the
heart to that side) or because the heart is "flipped" around and is
Dextrocardia with situs
inversus (reversed abdominal contents) is essentially a mirror image of
a heart, with a mirror image of the abdominal contents. In this
situation, the cardiac anatomy and connections are usually (but not
In dextrocardia with situs
solitus (normally-oriented abdominal contents), congenital cardiac
disease is more likely. The lesions are frequently complex and often
require surgical correction.
Clincally, the heart sounds
may be louder on the right than the left (and a diagnosis of left-sided
tension pneumothorax may erroneously be made prior to a radiograph being
available). There may be symptoms and signs of congenital heart disease
if associated anomalies are present. "Asymptomatic" dextrocardia may
present with features of Kartagener's syndrome (Primary Ciliary
Dyskinesia, PCD, leading to bronchiectasis and nasal symptoms).
For infants with situs inversus, referral to a Respiratory Service for
assessment of PCD is suggested.
Dextrocardia may also be an
incidental finding on a chest radiograph done for other reasons. In this
case, it is important to ensure that the radiograph has been correctly
Other Position Abnormalities
well as the general position in the chest that the heart occupies, it is
also important to define where the individual chambers of the heart are
placed. This is most easily done using echocardiography to define
atrial and ventricular positions. Defining the bronchial anatomy on
plain radiographs may also be useful.
There are a number of
potential abnormalities in position of the atria, ventricles, and
abdominal contents. It is also useful to define, in cases of
ambiguous abdominal contents, whether there is asplenia or polysplenia.
Complex cardiac anomalies are common in these situations. With
asplenia, there is a risk of overwhelming sepsis.
The image to the left shows
an infant with a relatively central cardiac silhouette. The NG
tube is seen draining to the right side of the abdomen. The liver
appears to be centrally placed. The echocardiogram demonstrated a
complex anomaly with pulmonary atresia, a common atrium, a large VSD,
and transposition of the great arteries.
Hypoplastic Left Heart Syndrome with Pulmonary Congestion
radiograph to the left shows pulmonary venous congestion in an infant with
hypoplastic left heart syndrome (HLHS).
Fetal echocardiography had
identified cardiac anomalies consistent with this sequence, with aortic
atresia and mitral stenosis. Of concern, the left atrium was large
and there was no clear atrial shunt to allow pulmonary venous return to
cross into the right atrium.
HLHS may be
antenatally on routine anatomy scan, primarily because the ventricles
are identified by their different sizes on the 4-chamber view.
Infants with HLHS who have a
reasonable atrial communication may have a radiograph which is not
markedly abnormal, and the baby may be reasonably well. However,
it is also one cardiac lesion
that can present at or soon after birth with an infant in poor condition
if there is poor atrial mixing through a restrictive atrial septum.
Because of the pulmonary congestion, the baby can have significant
respiratory distress and remain severely cyanosed.
is a right heart anomaly with downward displacement of the tricuspid valve
leaflets into the right ventricle. There is generally an ASD through
which there is right-to-left flow.
The tricuspid valve is
regurgitant, part of the right ventricle is in free communication with
the right atrium, the right atrium is enlarged (sometimes
spectacularly), and the right ventricular cavity can be small.
The radiograph to the left
demonstrate marked cardiac enlargement (a "carpet" heart).
The echocardiography images
to the left demonstrate a markedly enlarged right atrium and a
dysplastic tricuspid valve that does not fully close in systole (the
colour Doppler image shows marked tricuspid regurgitation). The
right ventricle in this example is a reasonable size but was functioning
poorly. The tricuspid valve was only mildly displaced into the right
There is a spectrum of
severity. Presentation in the newborn period with cyanosis usually
reflects a severe anomaly and the prognosis is poor. There may be
associated pulmonary hypoplasia if atrial enlargement restricts in-utero
pulmonary development. In older children, a mild anomaly may be
found as an incidental finding.
is usually reactive and resolves once the underlying cause resolves. It is
often seen in infants of diabetic mothers, and can be induced by
hypertension and by postnatal corticosteroids.
There may occasionally be
obstruction of the outflow tract. Medical treatment in severe cases
These radiographs are from a
macrosomic infant. The mother was not confirmed to have gestational
diabetes. The baby had respiratory distress and an initial radiograph
demonstrates marked cardiac enlargement and some plethora of the lung
fields. An echocardiogram showed normal connections and anatomy but
demonstrated marked ventricular hypertrophy - particularly of the septum
- without obstruction of the left ventricular outflow tract. The second
radiograph, taken at two weeks of age, shows a normal cardiac size with
clear lung fields.
Pericardial effusions may be seen in utero in association with fetal
hydrops. In this situation, they generally reflect poor cardiac output, and
are usually seen with other signs of hydrops (oedema, pleural effusions,
Postnatally, they may be due
to a number of causes also. An important cause to consider is
possible cardiac perforation from a UVC or
longline. In this
situation, aspiration of the pericardial fluid can lead to instant and
dramatic improvement in the clinical condition.
The images to the left show
an infant with a large pericardial effusion. The heart is large and the
lung fields are diffusely hazy.
The second image shown
follows insertion of a pericardial catheter. The cardiac size has
decreased and the lung fields look clearer. Note that there is now
significant subcutaneous oedema. There is also some right upper
Although a left SVC occurs in approximately 0.5% of the normal population,
it occurs in up to 4% of infants with congenital cardiac disease. It
usually drains into the coronary sinus.
The image to the left demonstrates
a persistent left SVC, nicely identified with the insertion of a longline
that has found its way down the aberrant vessel. The baby had normal
Non-cardiac Causes of Cardiac Failure
||It is important to consider non-cardiac causes
of cardiac failure in infants - not all large hearts have a primary
aetiology that is due to structural cardiac disease.
The image to the left shows the radiograph of an infant who presented on the
third day of life with signs of congestive cardiac failure. The heart
was structurally normal but grossly enlarged and demonstrated poor function.
The infant was in cardiac failure as a result of high output through a
vein of Galen malformation.
Non-cardiac causes of congestive cardiac failure include:
- AV malformations
- multiple haemangiomas
- severe anaemia
- renal failure
- severe systemic hypertension
- adrenal insufficiency
- metabolic diseases (e.g. Pompe disease)
- renal failure
Non-structural cardiac causes of congestive heart failure include:
- cardiac arrhythmias (e.g. sustained SVT, complete heart
- anomalous left coronary artery
November 29, 2011