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