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.
