Embryonic Clinical Correlations Flashcards
What is a ventricular septal defect? What affects the severity?
Hole in the wall of the interventricular sptum
- usu membranous
- can be muscular septal defect
Severity is dep. on size of the defect
- results in left to right blood shunt
What is an atrial septal defect?
What are the 3 fetal structures that give rise to them?
Hole in the interatrial septum
- presentation and severity depends on size of the defect
- often results in left to right blood shunt
Ostium Secundum defect
- excessive degeneration of suptim primum is one cause
- not enough septum secundum is another cause
Ostium Primim
- due to endocardial cushion defect
Common Atrium
- complete absence of atrial septum
- almost always assoc w/ other major heart defects
What causes an endocardial cushion defect? What are the results?
Cause:
underdeveloped endocardial cushions due to insufficient proliferation of neural crest cells
Results:
persistent atrioventricular canal
ostium primum defect (ASD)
membranous interventricular septum defect
What is an aortic/pulmonary valve stenosis?
Lumen of the pulm trunk or aorta is narrowed or completely occluded
- due to malformation of semilunar valve
Often presents with PFO and ductus arteriosus
What is the cause of the Tetralogy of Fallot? What are the 4 components?
Cause:
unequal division of truncus arteriosus by conotruncal ridges
4 parts:
- overriding aorta
- pulmonary stenosis
- ventricle septal defect
- R ventricular hypertrophy
What is the cause of transposition of great vessels? What is commonly seen?
Cause:
conotruncal ridges fail to spiral
- aorta rises from right ventricle
- pulm trunk arises from left ventricle
Usu occurs with patent ductus artiousus, PFO
What is the cause of persistent truncus artiosus? What are the results of the defect?
Cause:
conotruncal ridges fail to form
- undivided truncus receives blood from right and left ventricules
- usu occurs with patent ductus arteriosus, PFO
What is DiGeorge Syndrome?
Cause: deletion on long arm of chromosome 22 - abnormal neural crest development - cardiac abnormalities - usu defects of conotruncal ridge formation - craniofacial defects - thymic hypoplasia - parathyroid dysfxn
What is dextrocardia?
Heart loops in opposite direction
- mirror image lies in right thorax
- usu perfectly fxnal
What is ectopic cordis?
Heart lies on surface of chest
- usu results from failure of ventral body wall to close
What is a patent ductus arteriosus? (PDA)
Hole between aorta and pulm trunk, which normally closes after birth
- forms ligamentum arteriosum
Results in left-right blood shunt
- increased pulm blood flow
- decreased systemic blood flow
What is coarctation of the aorta? What are the 2 ways it presents?
Constriction of the aorta, unknown cause
Preductal - presents at birth
- collateral circulation doesn’t develop prenatally
Postductal - presents in late childhood and early adolescence
- doesn’t present in neonates due to collateral circulation between internal thoracic and intercostal arteries
What is a retroesophageal right subclavian artery?
Normally, subclavian comes from right 4th aortic arch
4th aortic arch degenerates
- leaves 7th intersegmental aa and small portion of dorsal aorta to form right subclavian artery
Differential growth shifts R subclavian to lie distal to origin of left subclavian
Condition doesn’t usu cause esophageal or tracheal constriction
- if constriction of esophagus occurs, called dysphagia lusorum
What is a double aortic arch?
Right dorsal aorta between original of 7th intersegmental arteries and fusion with L dorsal aorta
- vascular ring surrounding trachea and esophagus usu causes constriction
What happens when an absent inferior vena cava occurs?
Right subcardinal vein fails to make connection with the hepatic portion of inf vena cava
- caudal portion of body srains to azygos system of veins
