Topic 7 - the heart Flashcards
What are the three arteries that come of the aortic arch?
Left common carotid
Left subclavian
Innominate (brachiocephalic) artery (branches into the right subclavian and common carotid)
What does the ductus arteriosus form after birth?
the ligamentum arteriosum
What structures form the ductal arch in the fetus?
the pulmonary artery, ductus arteriosus and the descending aorta
What are the shunts unique to the fetal circulatory system?
Ductus venosus
Foramen ovale
Ductus arteriosus
What is mesocardia?
heart is central and apex points anteriorly
What is dextrocardia?
apex points to the right and it is predominantly in the right chest
What is dextroposition?
when the heart is pushed to the right by a mass or other external process
Outline the path of blood in the fetus
Oxygenated blood -> placenta -> umbilical vein -> ductus venosus -> IVC -> Right atrium -> shunted across the foramen ovale ->left atrium -> left ventricle -> aorta and foetal brain
Poorly oxygenated blood from the SVC -> right atrium -> right ventricle -> pulmonary artery -> shunted through the ductus arteriosus -> descending aorta -> mixes with blood from the proximal aorta.
descending aorta -> blood flows toward the placenta by way of the two umbilical arteries -> oxygen saturation in the umbilical arteries is approximately 58%.
What are the five sites of blood mixing in the fetus?
in the liver(i) by mixture with a small amount of blood returning from the portal system
in the inferior vena cava (ll) which carries deoxygenated blood returning from the lower extremities, pelvis. and kidneys
in the right atrium (Ill), by mixture with blood returning from the head and limbs
in the left atrium (IV), by mixture with blood returning from the lungs
and at the entrance of the ductus arteriosus into the descending aorta (V).
What happens to the fetal circulatory system after birth?
Closure of the umbilical arteries
Closure of the umbilical vein and ductus venosus
Closure of the ductus arteriosus
Closure of the oval foramen
What do the umbilical arteries become?
proximal part: superior vesical arteries
distal part: medial umbilical ligaments
What do the umbilical vein and ductus venosus become?
the umbilical vein forms the ligamentum teres
The ductus venosus forms the ligamentum venosom.
Why might a new born have normal cyanotic periods?
Crying of the baby creates a shunt from right to left at foramen ovale, thus accounting for cyanotic periods in the newborn.
How do the structures appear in an abdominal situs view. (stomach, aorta, IVC)
Stomach lies on the left, in the middle of the left half of the abdomen.
The aorta lies anterior and to the left of the spine.
The IVC lies anterior to the aorta and slightly to the right of the midline.
The IVC and aorta are similar in size, with the aorta more pulsatile.
What are the structures you should identify in a complete study of the heart?
atrial and ventricular septa the arch the duct cardiac connections (The heart has six connections, three on each side) the venous-atrial atrioventricular ventriculoarterial connections. Once those structures have been identified, the study is complete.
A complete examination of the heart includes identification of the cardiac connections. Name these connections.
The right-sided venous-atrial junction: the inferior and superior vena cava enter the right atrium
The right-sided atrioventricular junction: the tricuspid valve is the patent connection between the right atrium and ventricle
The right sided ventriculo-arterial junction: the pulmonary valve connects the right ventricle to the pulmonary artery
The left sided venous-atrial junction: the four pulmonary veins enter the left atrium
The left sided atrioventricular junction: the mitral valve is the patent connection between the left atrium and ventricle
The left-sided ventriculo-arterial junction: the aortic valve connects the left ventricle to the aorta
What can a hypoplastic right ventricle represent?
pulmonary atresia with an intact ventricular septum or with a ventricular septal defect
early severe pulmonary stenosis, and early tricuspid stenosis.
when the stenosis develops early, the right ventricle does not develop, and the right heart becomes hypoplastic.
If the stenosis occurs late (eg, after 20 weeks), then the right ventricle has already developed, and the tricuspid valve becomes incompetent, the blood regurgitates, and the right atrium enlarges.
What can hypoplastic left ventricle represent?
hypoplastic left heart syndrome with aortic atresia
early severe aortic stenosis or coarctation
early mitral stenosis or regurgitation
What can hyperplastic (large) right ventricle represent?
late pulmonary stenosis and late tricuspid regurgitation
an absent pulmonary valve with pulmonary regurgitation
a double-outlet right ventricle
What can right axis deviation indicate in the heart?
left-sided diaphragmatic hernia isomerism situs inversus inversion of the ventricles (in congenitally corrected transposition or levotransposition) atrioventricular septal defects a double-outlet right ventricle a common atrium
What does a vein behind the heart mean in 4ch?
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.
What can a right sided aorta mean?
This may be seen in some conotruncal anomalies such as
tetralogy of Fallot
truncus arteriosus
pulmonary atresia with a ventricular septal defect
and an absent pulmonary valve
could be an isolated sign in a fetus with a right-sided aortic arch.
(terminology that refers to the position of the arch compared to the trachea, not the absolute position of the arch in the chest).
What can cause global ischaemia of the heart?
endocardial fibroelastosis fetal anemia storage disorders ischemia infections
What may cause thickened myocardium?
hypertrophic cardiomyopathies univentricular hearts (but the septum would be decreased or absent) septal hypertrophy in fetuses of diabetic patients (in which cases, the septum is predominantly affected)
What can cause an enlarged right ventricle?
Tachyarrhythmias Ebstein and Uhl anomalies idiopathic right atrial enlargement a common atrium pulmonary atresia with a regurgitating tricuspid valve, pulmonary stenosis with an intact septum, and premature closure of the foramen ovale or ductus arteriosus
What can pericardial fluid signify?
can be present normally (up to 7mm i believe) 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
Whhat can it mean if the stomach is located on the opposite side to the heart?
This may be called many different names, such as heterotaxy, situs ambiguous, and visceral situs.
Why is stomach on the opposite side to the heart significant?
If they are not on the same side, there is a high risk (>95%) of cardiac anomality
How can you check whether a vsd is real or not?
using multiple scanning planes to view the regions, preferably with the scan plane perpendicular to the septum; and
using colour flow imaging.
What are some causes of septal override?
tetralogy of Fallot
pulmonary atresia with ventricular septal defect
double outlet right ventricle
aortic atresia with ventricular septal defect
truncus arteriosus
What can Absence of the criss-cross pattern of the aorta and pulmonary outflow tract mean?
abnormality of the great vessels, as in double outlet right ventricle or transposition of the great arteries.
When does the pulmonary artery usually appear larger than the aorta?
severe aortic stenosis;
aortic atresia; and
coarctation with VSD
When might the aorta appear larger than the pulmonary artery?
tetralogy of Fallot;
severe pulmonary stenosis; and
pulmonary atresia.
truncus arteriosus
When may only a single great artery arise?
either one of the great arteries is atretic; or
truncus arteriosus is present.
How does double aortic arch appear?
Branching of LVOT.
Each has its own common carotid and subclavian
forms a ring round trachea and esophagus
What does a vein on the left side of the pulmonary artery mean?
Persistent left vena cave.
Drains into left atrium or coronary sinus
What can enlarged superior vena cava mean?
- inferior vena cava interruption with azygos or hemizygos continuation
- anomalous pulmonary venous return with a supracardiac connection
- increased circulation of the brain, as found in a vein of Galen aneurysm
What does great vessels in parallel mean?
transposition of the great arteries
What does a right pointing arrow view mean?
Right sided aortic arch
What does a u shaped arrow view mean?
• sign of a right-sided aortic arch
Antegrade flow in the aorta and retrograde flow in the pulmonary artery mean?
Pulmonary atresia
What does it mean when a thin pulmoary artery arises from the aorta?
truncus arteriosus
What does it mean when the pulmonary artery is bigger than the aorta?
coarctation of the aorta
Antegrade flow in the pulmonary artery, retrograde flow in the aorta mean?
hypoplastic left heart syndrome
What is an overriding aorta?
congenital heart defect where the aorta is positioned directly over a ventricular septal defect, instead of over the left ventricle
What happens to the blood when an overriding aorta is present?
The result is that the aorta receives some blood from the right ventricle, which reduces the amount of oxygen in the blood
What appearance of the pulmonary artery may be present with an overriding aorta and what does it mean?
When the pulmonary artery appears normal in size, we are probably dealing with a malalignment ventricular septal defect in a mild form of tetralogy of Fallot. When the pulmonary artery is thin, then classic tetralogy of Fallot is the most likely diagnosis.
What are two types of ASD?
Ostium secundum ASD is caused by the excessive resorption of the septum primum or by inadequate growth of the septum secundum
Ostium primum ASD is 2nd most common, located near the AV valves
Associated with AVSD
What are the different classifications of VSD?
membranous or muscular VSD (inlet, trabecular, outlet)
What is the most common vsd?
membranous 80%
What is strongly associated with AVSD?
Trisomy 21 and 2/3 have other cardiac abnormalities
What are the two types of AVSD?
In complete AVSD (97%) a single, multileaflet valve is present
in incomplete AVSD two of the leaflets (bridging leaflets) are connected by a narrow strip of tissue
What cardiac malformations are associated with AVSD?
septum secundum ASD hypoplastic left heart syndrome (HLHS) valvular pulmonary stenosis coarctation of the aorta tetralogy of Fallot (TOF)
What extra cardiac abnormalities are associated with ASVD?
Omphalocele Duodenal atresia Facial clefts Cystic hygroma Neural tube defects Multicystic kidneys
What is ebstein anomaly?
Inferiorly displaced tricuspid valve
What are some association of ebstein anomaly?
a variety of structural cardiovascular defects such as pulmonary atresia or stenosis, arrhythmias and chromosomal abnormalities
How can you diagnose ebstein anomalay on ultrasound?
apical displacement of the tricuspid valve in the right ventricle, an enlarged right atrium and the reduction in size of the right ventricle
What are some differential diagnoses for ebstein anomaly?
tricuspid valvular dysplasia
Uhl anomaly
idiopathic right atrial enlargement
none of these has an inferiorly displaced tricuspid valve, the most reliable sign of Ebstein anomaly.
What causes hypoplasia of the right ventricle?
Hypoplasia of the right ventricle develops because of a reduction in blood flow secondary to inflow imped
What are sonographic appearances of hypoplastic right ventricle?
Small, hypertrophic right ventricle
Small or absent pulmonary artery
Pulse Doppler may demonstrate decreased flow through the tricuspid valve or pulmonary artery
What are some poor prognostic factors for hypoplastic left heart syndrome?
Poor prognostic signs in-utero include monophasic flow across the mitral valve, restricted flow through the foramen ovale and retrograde flow through the aorta
What is tetralogy of fallot?
VSD
Overriding aorta (reliably seen)
Hypertrophy of the right ventricle (rarely occurs in utero)
Stenosis of the right ventricular outflow tract
What is TOF associated with?
cardiac and extracardiac abnormalities and chromosomal anomalies
What view is best for assessing TOF?
5 chamber view (LVOT)
What does right sided aortic arch look like?
U shaped arrow. Aorta goes around trachea
What is truncus arteriosus?
single large vessel arising from the base of the heart
This vessel supplies the coronary arteries and the pulmonary and systemic circulations
What views can you see truncus arteriosus on?
4CH and outflow tract views
When can double outlet right ventricle be diagnosed sonographically?
more than 50% of both the aorta and the pulmonary artery arise from the right ventricle
What are some differentials for Truncus?
TGA
Tetralogy of Fallot
Is TGA associated with chromosomal abnormalities?
No
What are the two types of TGA?
Complete or dextrotranspoition which occurs in 80% of cases
Congenitally corrected or levotransposition which occurs in 20% of cases
What is Ventriculoarterial discordance?
Aorta arises from the right ventricle, the pulmonary artery arises from the left ventricle
What is complete transposition?
defined as AV concordance (atria and ventricles are correctly paired) with VA Ventricular-arterial discordance
What does TGA look like sonographically?
Demonstrate that the great vessels exit the heart in parallel, rather than crossing
3VV will only display the aorta
What is congenitally corrected TGA?
Congenitally corrected TGA is characterised by AV discordance with VA discordance
How do you differentiate complete and congenitally corrected TGA?
Differentiating the two types entails identification of the morphologic right nad left ventricles
What are some associations of coarctation of the aorta?
Abnormal aortic valve
VSD
DORV (double outlet right ventricle)
AVSD
Is coarctation associated with aneuploidy?
No
What is asplenia (right sided isomerism)?
Makes everything the right Bilateral right-sidedness Right atrial isomerism Bilateral trilobed lungs Bilateral right bronchi Bilateral right pulmonary arteries Ipsilateral location of both aorta and IVC Absence of the spleen Midline horizontal liver Bilateral superior vena cavae Severe and complex heart anomalies
What is polysplenia (left sided isomerism)?
Bilateral left-sidedness Left atrial isomerism Interruption of the IVC Azygous continuation of the IVC Multiple spleens Complete atrioventricular block
What is a rhabdomyoma?
Solid, echogenic mass
Can be singular or multiple
May develop in utero after an initially normal foetal echo
Associated with tuberous sclerosis
What is an echogenic intracardiac focus?
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
What is ectopia cordis?
Heart located outside the thoracic cavity
What are the indications for specific evaluation of fetal heart rhythm by fetal echocardiography? Define these indications.
persistent heart rate irregularity: > 10-15 premature contractions per minute
prolonged fetal tachycardia: tachycardia is > 180 bpm
prolonged fetal bradycardia: bradycardia is < 100 bpm
unexplained fetal hydrops
patients at risk for developing arrhythmias: maternal systemic lupus erythematosus (SLE), prior affected fetus
Why is the potential for 3d and 4d heart important?
provides opportunity to obtain views which are otherwise unobtainable because of fetal lie
enormous opportunity for review normal and abnormal hearts once the patient has left the department
In remote centres, it provides the opportunity to have the heart re-evaluated in a tertiary centre without requiring the patient to travel.
