Heart

Question 1

What are unique shunts in the foetal cardiovascular system?

Answer 1

Ductus arteriousus
Ductus venosus
Foramen ovale

Question 2

Describe the blood flow throughout the heart

Answer 2

Oxygenated blood leaves the placenta through the umbilical vein and travels through the ductus venosus and the IVC to the foetal right atrium
This blood is shunted across the foramen ovale to the left atrium then the left ventricle, aorta and foetal brain
Poorly oxygenated blood from the SVC enters the right atrium and right ventricle and pulmonary artery, then is shunted through the ductus arteriosus into the descending aorta where it mixes with blood from the proximal aorta.
After coursing through the descending aorta, blood flows toward the placenta by way of the two umbilical arteries. The oxygen saturation in the umbilical arteries is approximately 58%.

Question 3

What happens after birth to the umbilical arteries?

Answer 3

proximal part: superior vesical arteries

distal part: medial umbilical ligaments

Question 4

What happens after birth to the umbilical vein and ductus venosus?

Answer 4

After obliteration, the umbilical vein forms the ligamentum teres
The ductus venosus forms the ligamentum venosom.

Question 5

What happens after birth to the ductus arteriosus?

Answer 5

In the adult, the obliterated ductus arteriosus forms the ligamentum arteriosum.

Question 6

What happens after birth to the foramen ovale?

Answer 6

Closure of the oval foramen
caused by an increased pressure in the left atrium, combined with a decrease in pressure on the right side.
Crying of the baby creates a shunt from right to left, thus accounting for cyanotic periods in the newborn.
In 20% of all individuals perfect anatomical closure may never be obtained

Question 7

Describe the 4CH

Answer 7

Most important view.
Demonstrates the right and left atria and ventricles.
The pulmonary vein should be seen entering the left atrium.
The tricuspid valve is seen between the right atrium and ventricle.
The mitral valve is seen between the left atrium and ventricle.

Question 8

Describe the LVOT

Answer 8

This view illustrates the left-sided ventriculoarterial connection and the perimembranous and muscular parts of the ventricular septum.
The aorta arises in the center of the chest, in the center of the heart.
The aorta arises between the two AV valves.
There is aortic–mitral continuity posteriorly.
There is aortic–septal continuity anteriorly.
The muscular and perimembranous septum appears intact.

Question 9

Describe the 3VV

Answer 9

The three vessels are seen lying from left to right: the PA, the Ao, and the SVC, respectively. (PAS)
They are in descending order of size: PA > Ao > SVC (PAS)
Each lies slightly posterior to the other: the PA is anterior to the Ao, the Ao is anterior to the SVC. (PAS)
The PA arises close to the anterior chest wall.
The pulmonary valve (PV) lies anterior and cranial to the aortic valve.
The PA crosses over the aortic origin.
The pulmonary trunk and its ductal continuation is directed straight posteriorly.
The arterial duct connects to the descending Ao just to the left and in front of the spine.
The PA branches into the right pulmonary artery (RPA) and duct.

Question 10

Describe the arrow view

Answer 10

Duct and arch are of similar size.
Duct and arch join distally just in front and to the left of the spine.
The direction of blood flow in both vessels is the same.

Question 11

What is the vein behind the heart?

Answer 11

There is a vein behind the 4-chamber view. It would be tempting to think this is the inferior vena cava, but at the level of the 4-chamber view, the inferior vena cava has already drained into the right atrium. This vessel represents the azygous or hemizygous continuation of an inferior vena cava interruption. This finding can be isolated or a part of left isomerism, a condition called “polysplenia” in the past.

Question 12

What is the normal measurement of pericardial fluid and when is it abnormal?

Answer 12

can be present normally (up to 7mm)
can be a sign of many conditions, such as;
trisomy 21
a hypoplastic left heart
teratoma
rhabdomyoma
hemangioma
tachyarrhythmia
chorioangioma
sacrococcygeal teratoma
an atrioventricular septal defect
cardiomyopathy
Rh disease
renal agenesis
posterior urethral valves
twin-twin transfusion syndrome

Question 13

Why do you sometimes see a ‘pseudo’ ventricular septum defect (VSD)? What can you do to check whether the VSD is real or not?

Answer 13

The membranous portion of the interventricular septum (lying just below the atrio-ventricular valves) is thin and may not be visualised if scanned parallel to the scan plane and consequently appears to be a membranous VSD. This can be avoided by:
using multiple scanning planes to view the regions, preferably with the scan plane perpendicular to the septum; and
using colour flow imaging.

Question 14

What does absence of the criss-cross pattern represent?

Answer 14

Absence of the criss-cross pattern of the aorta and pulmonary outflow tract implies an abnormality of the great vessels, as in double outlet right ventricle or transposition of the great arteries.

Question 15

List some causes of septal override in cases of a VSD

Answer 15

tetralogy of Fallot
pulmonary atresia with ventricular septal defect
double outlet right ventricle
aortic atresia with ventricular septal defect
truncus arteriosus

Question 16

When does the pulmonary artery appear larger?

Answer 16

severe aortic stenosis;
aortic atresia; and
coarctation with VSD.

Question 17

When does the aorta appear larger than the pulmonary artery?

Answer 17

tetralogy of Fallot;
severe pulmonary stenosis; and
pulmonary atresia.

Question 18

When is there only 1 great artery?

Answer 18

Great artery atresia

truncus arteriosus

Question 19

Describe an AVSD

Answer 19

Spectrum of abnormalities that involve varying degrees of deficiency in the interatrial and interventricular septa and the mitral and tricuspid valves
⅔ of foetuses with AVSD have additional cardiac anomalies
Trisomy 21 is strongly associated with AVSD
In complete AVSD a single, multileaflet valve is present
in incomplete AVSD two of the leaflets (bridging leaflets) are connected by a narrow strip of tissue, resulting in the appearance of two valve orifices
Sonographically, a defect in the atrial or ventricular septum with an associated single abnormal A-V valve is visible in a four-chamber view

Question 20

What cardiac malformations is AVSD related to?

Answer 20

Cardiac malformations associated with AVSD include;
 septum secundum ASD
hypoplastic left heart syndrome (HLHS)
valvular pulmonary stenosis
coarctation of the aorta
tetralogy of Fallot (TOF)

Question 21

What are some commonly associated extra-cardiac anomalies with AVSD?

Answer 21

Commonly associated extracardiac anomalies:
Omphalocele
Duodenal atresia
Facial clefts
Cystic hygroma
Neural tube defects
Multicystic kidneys

Question 22

What is the Ebstein anomaly?

Answer 22

Characterised by Inferior displacement of the tricuspid valve
Associated with a variety of structural cardiovascular defects such as pulmonary atresia or stenosis, arrhythmias and chromosomal abnormalities
Sonographic diagnosis rests on apical displacement of the tricuspid valve in the right ventricle, an enlarged right atrium and the reduction in size of the right ventricle
Arrhythmias, particularly supraventricular tachycardias (SVTs), are common with Ebstein anomaly

Question 23

What is hypoplastic right ventricle?

Answer 23

Generally occurs secondary to pulmonary atresia with intact interventricular septum
May also be associated with tricuspid atresia, however not as common
Hypoplasia of the right ventricle develops because of a reduction in blood flow secondary to inflow impedance from tricuspid atresia or outflow impedance from pulmonary arterial atresia
Sonographic findings:
Small, hypotrophic right ventricle
Small or absent pulmonary artery
Pulse Doppler may demonstrate decreased flow through the tricuspid valve or pulmonary artery
Congestive heart failure and hydrops may occur from tricuspid regurgitation. After birth, death usually follows closure of the ductus arteriosus.

Question 24

What is hypoplastic left heart syndrome?

Answer 24

Left ventricular cavity is pathologically reduced
Small left ventricle results from decreased blood flow into or out of the left ventricle
Abnormalities:
Aortic atresia
Aortic stenosis
Mitral valve atresia
It is associated with coarctation of the aorta
Sonographically:
Small left ventricle
Hypoplastic or atretic mitral valve and aorta
Colour demonstrates absences of flow through the mitral and aortic valves
Poor prognosis → 25% mortality in the first week and untreated infants dying within 6 weeks
Poor prognostic signs in-utero include monophasic flow across the mitral valve, restricted flow through the foramen ovale and retrograde flow through the aorta

Question 25

What is a univentricular heart?

Answer 25

Two atria empty into a single ventricle via two AV valves or a common AV valve Results from the failure of the interventricular septum to develop The single chamber has a left ventricular morphology in 85% of cases Associated cardiac anomalies are common Asplenia or polysplenia (isomerism) occurs in 13% of cases Sonographically: A single ventricle with an absent interventricular septum is seen Doppler determines if a normal outflow tract is present Non-functioning, rudimentary accessory ventricle may be present

Question 26

What does tetralogy of Fallot consist of?

Answer 26

Consists of: VSD Overriding aorta (reliably seen) Hypertrophy of the right ventricle (rarely occurs in utero) Stenosis of the right ventricular outflow tract

Question 27

Describe the ultrasound appearance of ToF

Answer 27

There is incomplete closure of the interventricular septum which causes the aorta to override both ventricles VSD typically occurs in the perimembranous portion of the septum Pulmonary atresia or stenosis may be seen Newborns with pulmonary stenosis rather than atresia are generally asymptomatic at birth but develop cyanosis and a murmur in the first weeks of life Surgery is often performed successfully

Question 28

Describe the ultrasound appearance of a right-sided aortic arch

Answer 28

There is 'U' configuration of pulmonary artery and aortic arch. Trachea is seen within 'U'. 4 chamber view, LVOT-RVOT are normal.

Question 29

Describe truncus arteriosus

Answer 29

Characterised by a single large vessel arising from the base of the heart This vessel supplies the coronary arteries and the pulmonary and systemic circulations Aortic anomalies occur in 20% of cases Non-cardiac anomalies occur in 48% of cases VSD is almost always present Four types: Has a pulmonary artery that bifurcates into right and left branches after it arises from the ascending portion of the truncal vessel Has right and left pulmonary arteries arising separately from the posterior truncus Has pulmonary arteries that arise from the sides of the proximal truncus Has systemic collateral vessels from the descending aorta as a source of flow A single, large truncal artery with overriding of the ventricular septum and an associated VSD is identified on the 4CH and outflow tract views Colour Doppler facilitates accurate localisation of the pulmonary arteries and detects truncal valvular insufficiency

Question 30

Describe the double outlet right ventricle

Answer 30

Occurs when more than 50% of both the aorta and the pulmonary artery arise from the right ventricle Three types: Aorta posterior and to the right of the pulmonary artery Aorta and pulmonary artery parallel, with the aorta to the right Aorta and pulmonary artery parallel, with the aorta anterior and to the left Particularly associated with VSD, various extracardiac defects, foetal chromosomal anomalies, maternal diabetes and maternal alcohol consumption Sonographically: The aorta and pulmonary artery arise predominantly from the right ventricle

Question 31

Describe complete transposition of the great arteries

Answer 31

Complete transposition is defined as AV concordance (atria and ventricles are correctly paired) with VA Ventricular-arterial discordance There also may or may not be a VSD Varying cardiac anomalies may be present, such as pulmonary stenosis Aorta arises from the right ventricle and receives systemic blood and returns it to circulation The pulmonary artery arises from the left ventricle, receives pulmonary venous blood, and returns is to the lungs After birth, the closure of the ductus arteriosus and the foramen ovale causes this condition to be incompatible with life unless an associated shunt allows the mixing of right and left circulations Requires immediate treatment Sonographically: Demonstrate that the great vessels exit the heart in parallel, rather than crossing 3VV will only display the aorta

Question 32

Describe corrected transposition of the great arteries

Answer 32

Congenitally corrected TGA is characterised by AV discordance with VA discordance Aorta arises from the left sided morphologic right ventricle and is anterior and to the left of the pulmonary artery Pulmonary arises from the right sided morphologically left ventricle VSDs and pulmonary stenosis occurs in 50% of cases Malformation and inferior displacement of the morphologic tricuspid valve may be present Blood flow may be normal Morphologic right ventricle is on the left and morphologic left ventricle is on the right

Question 33

How would you differentiate between corrected and complete transposition of the great arteries?

Answer 33

Differentiating the two types entails identification of the morphologic right and left ventricles Moderator band is seen on the left Tricuspid valve seen on the left and is more apical

Question 34

What are the two subgroups of anomalous pulmonary venous return

Answer 34

Total anomalous pulmonary venous return. None of the pulmonary veins drain into the left atrium Partial anomalous pulmonary venous return At least one of the pulmonary veins has an anomalous connection

Question 35

Describe coarctation of the aorta

Answer 35

Narrowing of the aortic lumen, usually between the insertion of the ductus arteriosus and the left subclavian artery There may only be slight narrowing at the distal end of the arch, all the way to severe hypoplasia of the entire arch Almost all cases are associated with other cardiac anomalies such as: Abnormal aortic valve VSD DORV - what dis (double outlet right ventricle) AVSD Not commonly associated with chromosomal anomalies (5%) Sonographically: Difficult to detect Ventricular size discrepancy with a prominent right ventricle and smaller left ventricle A right-to-left ventricle diameter ratio more than 2 SD above the norm suggests coarctation Colour can identify areas of narrowing Spectral can identify increased flow distal to a narrow segment

Question 36

Describe aortic stenosis

Answer 36

Stricture or obstruction of the ventricular outflow tract Occurs in 5.2% of all newborns Supravalvular, valvular and subvalvular Supravalvular aortic stenosis occurs ABOVE the sinuses of Valsalva Valvular aortic stenosis is associated with a bicuspid aortic valve and chromosomal anomalies Subvalvular aortic stenosis is associated with inherited asymmetrical septal hypertrophy and hypertrophic obstructive cardiomyopathy Sonographically: Thickening of the aortic valve poststenotic dilation of the aorta ventricular enlargement are clues to valvular aortic stenosis real-time evaluation of the aortic valve may show it persisting, as opposed to moving normally in and out of the field of view. Thickening of the interventricular septum may be seen in subvalvular aortic stenosis. In all cases, increased velocity through the aortic valve will be identified on pulsed Doppler ultrasound. Early-onset aortic stenosis results in endocardial fibroelastosis (EF) and hypoplastic left ventricle

Question 37

Describe pulmonary stenosis

Answer 37

May occur at valve level or at the infundibulum Occurs in 7.4% of newborns Dysplastic and stenotic pulmonic valves are seen in Noonan syndrome and maternal rubella Pulmonic stenosis is associated with TAPVR, ASD, supravalvular aortic stenosis and tetralogy of Fallot Can occur in the recipient of TTTS Heart becomes hypertrophic secondary to the increased preload Sonographically: Increased velocity through the pulmonic valve Hypertrophy of the right ventricle Tends to progress in utero Balloon valvuloplasty in utero is in its early phases of attempts

Question 38

Describe the cardiosplenic syndromes.

Answer 38

syndromes associated with asplenia (right isomerism) and polysplenia (left isomerism). Both are defects of lateralization in which symmetrical development of normally asymmetrical organs or organ systems occurs. Asplenia (Ivemark syndrome) and polysplenia syndromes are usually considered separate clinical entities. However, they have many characteristics in common, including situs inversus or situs ambiguus of various visceral organs, complex congenital heart defects, and increased incidence of chronic arrhythmias

Question 39

Describe a rhabdomyoma

Answer 39

``` Rhabdomyomas sonographically: Solid, echogenic mass Can be singular or multiple May develop in utero after an initially normal foetal echo Associated with tuberous sclerosis ```

Question 40

Describe echogenic foci

Answer 40

Thought to represent areas of mineralisation of papillary muscle or chordae tendinae 93% occur in the left ventricle but can occur in the right or both Generally clinically insignificant In isolation, in a low risk pregnancy, there is no increased risk of anueploidy

Question 41

What is cardiomyopathy caused by and how does it sonographically appear?

Answer 41

``` Can be caused by viral and bacterial infections inborn errors of metabolism endocardial fibroelastosis familial cardiomyopathy maternal diabetes Sonographically: Demonstration of hypertrophy of the ventricular wall or septum Non-obstructive cardiomyopathy can be diagnosed by demonstrating dilation of one or more cardiac chambers ```

Question 42

What is ectopia cordis

Answer 42

RARE Heart is located outside the thoracic cavity Results from a failure of fusion of the lateral body fold in the thoracic region Four types: Thoracic (60%) Heart is displaced from the thoracic cavity through a sternal defect Abdominal (30%) Heart is displaced into the abdomen through a diaphragmatic defect Thoracoabdominal (7%) Heart is displaced from the chest through a defect in the lower sternum, with associated diaphragmatic or ventral abdominal wall defect Pentalogy of Cantrell Cervical (3%) Heart is displaced to the neck region Most cases are isolated Can be associated with pentalogy of Cantrell ``` Pentalogy of Cantrell: Sternal cleft Ventral diaphragmatic hernia Omphalocele Intracardiac anomalies Ectopia cordis ```

Question 43

What is tachycardia

Answer 43

Heart rate greater than 180bpm

Question 44

What is bradycardia

Answer 44

Prolonged heart rate of 100bpm or less Transient bradycardia may be related to an increase in intrauterine pressure occasionally secondary to transducer pressure or foetal compression No clinical significance

Question 45

What is congenital heart block?

Answer 45

Failure of transmission of impulses from the atrium to the ventricles results in atrioventricular block