Abnormal Cardiovascular Development Flashcards
What is ectopia cordis and what is believed to cause this condition?
It’s when the heart forms outside the thoracic wall due to failure in folding of the lateral body wall
Describe the development of dextrocardia.
This happens if the developing heart tube turns to the left instead of the to the right
What developmental structures and events are responsible for the four clinically significant type of atrial septal defects?
It’s an abnormal opening between the right and left atria - we usually get a flap over the foramen ovale to close it
Four possibilities
- excessive resorption of primary septum leading to patent foramen ovale
- Incomeptent foramen ovale due to hypoplastic growth of the secondary septum (foramen too large)
- inadequate development of primary septum - doesn’t reach the cushion - forming a basal opening
- the sinus venosus develops abnormally and doesn’t join the primitive atrium appropriately, causing a high atrial septal defect
How do the atrial septal defects manifest clinically after birth?
Large shunts lead to pulmonary hypertension as blood from the left atrium over to the right to enter the pulmonary system.
you get cyanosis several months or years after birth
if it’s not dealt with, you get pulmonary fibrosis, right ventricular failure and paradoxical embolism
Describe the developmental abnormalities occurring in ventricular septal defects.
You have abnormal formation of the endocardial cushions and aorticopulmonary septum, so you don’t have the membranous portion of the interventricular septum (the upper part)
Sometimes you have muscular septum involvment as well - usually at multiple sites (swiss cheese septum)
How are ventricular septal defects clinically manifested?
cyanosis tardive in long-standing cases
murmurs
Note - 50% close spontaneously!
Often associated with other abnormalities
Describe the types of coarctation of the aorta that may occur.
Coarctation is a narrowing of the aorta, typically immediately at the area where the ductus arteriosus comes off
types depend on whether the narrowing occurs distal or proximal to the ductus arteriosus: postductal (adult form and most common) and preductal (infant form)
What are the clinical manifestations of coarctation of the aorta?
For the postductal in adults:
- BP increased in arms, but decreased in legs
- intercostal artery blood flow is increased, leading to notched ribs as the large vessels cause resorption of the bone
- weak pulses in lower extremities
- complications of CHF, CVA, AOrtic rupture and infection
What happens in patent ductus arteriosus? Describe the clinical situations can cause this.
The ductus arteriosus fails to close. because pressure in the aortic system is higher than in the pulmonary, blood is moved form the aorta into the pulmonary trunk
Living at high altitudes, maternal rubella infection
How can patent ductus arteriosus be treated?
in preemies, give ibuprofen to inhibit prostaglandin formation and promote closure
in others - catheter-placed occluder
Describe the clinical features of patent ductus arteriosus
a continuous machine-like murmur or thrill
reversed blood flow causes cardiomegaly, increased pulmonary vascularity, heart failure, pulmonary hypertension and endocarditis is common
Describe the cardiac abnormalities associated with a right-to-left shunt.
The three Ts!
Tetralogy of Fallot
Transposition of the great arteries
Truncus arteriosus (persistent)
What are the clinical signs related to right to left shunts.
cyanosis at birth
Describe the cardiac abnormalities that cause left to right shunts.
atrial septal defects
ventricular septal defects
patent ductus arteriosus
What are the clinical signs of a left to right shunt?
no cyanosis or cyanosis tardive
exercise intolerance
Describe the development of late cyanotic congenital heart disease or Eisenmenger syndrome.
With left to right shunts, the blood builds up on the right side, increasing the work necessary for the right ventricle and pulmonary system.
over time, this leads to right sided ventricular failure and pulmonary hypertension leads to pulmonary fibrosis
the ventricular failure and fibrosis means the blood doesn’t get reoxygenated appropriately, leading to a delayed cyanosis later in life
How is coarctation of the aorta an obstructive congenital heart defect?
because you get such severe narrowing of the aorta that the patient can’t get enough blood flowing thorugh and must develop collateral circulation
Describe the developmental defects related to the tetralogy of Fallot - the sequence of development.
- ventricular septal defect
- pulmonary stenosis
- overriding (large) aorta which gains access to the right ventricle)
- right ventricular hypertrophy
What are the clinical signs associated with tetralogy of fallot?
cyanosis within the first weeks of life
over time you get the ventricular hypertrophy
paradoxical embolism
infective endocarditis
Describe the developmental defect related to transposition of the great arteries.
the bulbotruncal ridges don’t form appropriately so you don’t get the right spiraling of the aorticopulmonary septum. This means the aorta originates from the right ventricle and the pulmonary artery from the left ventricle
What are the clinical symptoms of transposition of the great arteries.
It’s incompatible with life!!!! Unless you also have atrial and ventricular septal defects and a PDA to allow mixing of the oxygenated and deoxygenated blood so at least the blood going to the tissues will have SOME oxygen in it
What shunts may be involved in transposition of the great arteries
atrial septal defect
ventricular septal defect
patent ductus arteriosus
Describe the developmental defect related to a patent truncus arteriosus.
The bulbar and truncal ridges fail to develop so you don’t get the aorticopulmonary septum and you don’t have a separate atrium and pulmonary trunk - just a common aorticopulmonary outlet receiving blood from both ventricles
What are the clinical signs of patient truncus arteriosus?
there is mixing of oxygenated and deoxygenated blood, so you get a cyanosis tardive and increased pulmonary blood flow leading to irreversible pulmonary hypertension and fibrosis
Describe the clinical differences between a preductal and postductal coarctation.
For the postductal in adults:
- BP increased in arms, but decreased in legs
- intercostal artery blood flow is increased, leading to notched ribs as the large vessels cause resorption of the bone
- weak pulses in lower extremities
- complications of CHF, CVA, AOrtic rupture and infection
For preductal in infants:
- early CHF
- patent ductus arteriosus
- cyanosis of lower body!!!!
- increased mortality
What is the difference with clinical signs of a patent ductus arteriosus versus coarctation of the aorta without PDA?
In PDA you have late cyanosis in the entire body. in PDA you get pulmonary hypertension.
in coarctation you can either have no cyanosis or cyanosis of the lower body only. here you have hypertension in upper extremities, but not in lower extremities.
What developmental structure is repsonsible for the occurrence of either pulmonary or aortic stenosis?
Asymmetrical division or spiralling of the aorticopulmonary septum (bulbar and truncal ridges)
What heart defects are associated with maternal rubella infection?
patent ductus arteriosus, but also pulmonary stenosis and ventricular septal defects
(along with cataracts and deafness)
What heart defect is associated with diabetes in the mother?
transposition of the great arteries (more common in male babies)
In summary
what shunts are involved with blue babies and which are involved with blue kids?
Right to left = blue babies
tetrology of fallot
transposition of great vessels
truncus arteriosus persistent
Left to right = blue kids
artial or ventricular septal defects
patent ductus arteriosus
What heart defects are associated with DiGeorge Syndrome (deletion of chromosomes 22q11)
tetralogy of fallot truncus arteriosus (persistent)
What heart defects are associated with down syndrome?
atrial septal defect
ventricular septal defect
What heart defect is associated with turner syndrome?
coarctation of the aorta
What congenital heart defect is associated with marfan syndrome
aortic stenosis
