Intro to Fetal Echocardiography Flashcards
When is the most sensitive period in the 1st trimester for cardiac development?
3.5-6.5 weeks
What is the 1st organ system to reach a functional state?
cardiovascular
What happens at the end of the 3rd week of dev?
circulation of blood has begun
What happens in the 5th week of dev?
heart begins to beat
Blood flow in the fetus varies in what two respects from the neonatal stage?
- communication is open between the right and left sides of the heart through the fossa ovale
- between the aorta and the pulmonary artery via the ductus arteriosus
Where does most of the blood in the right ventricle go?
passes thru the ductus arteriosus into the descending aorta, only a small amount goes to the lungs
How many pulmonary veins are there and where do they enter the LA?
4, posterior wall
What body parts are fed via the three branches off the Ascending Aorita?
head, neck, upper torso
What are the three branches off the AA?
Innominate artery, Left carotid artery, Left subclavian artery
Mixed blood in te descending aorta goes where?
passes into umbilical arteries and is returned to the placenta for reoxygenation
What fetal cardiac structures are no longer necessary after birth?
- foramen ovale
- ductus arteriosus
- ductus venosus
- umbillical vessels
Omission of the placental circulation causes what?
- an immediate fall of BP in iVC and RA
- as lungs expand with air, there is a fall in pulmonary vascular resistance, causing an increase in pulmonary blood flow and thinning of the walls of pulmonary arteries
What causes the foramen ovale to close?
pressure in the LA is higher than that in the RA
When does ductus arteriosus usually constrict?
shortly after birth (within 24-48 hours) once left-sided pressures exceed the right-sided pressures
What is patent ductus arteriosus?
small shunt of blood from the aorta to the pulmonary artery
What constricts after birth to prevent blood loss in neonate?
umbilical arteries
T/F: The umbilical vein may remain patent for some time after birth?
True
Describe normal HR for 1st trimester?
HR begins around 90 bpm and increases to 170 bpm before returning to a normal rate and sinus rhythm
How many bpm qualifies for bradycardia?
<60 bpm
Bradycardia places fetus at high risk for what?
associated heart disease and fetal echocardiography should be performed to rule out the presence of a structural heart defect
What # bpm qualifies as tachycardia?
> 200 bpm