[216B] Congenital Heart Defects Flashcards
What’s an echocardiogram?
Ultrasound of the heart.
What are 3 anatomical structures present in fetal circulation that should not be present after birth?
- Ductus venosus.
- Foramen ovale.
- Ductus arteriosus.
Why do fetuses have increased pulmonary resistance?
They still have fluid in their lungs.
What physiological changes would we expect to see with the heart muscle after the transition to postnatal circulation? Why?
RV hypertrophy: must overcome pressure to pump blood into the lungs.
Which notable genetic condition is associated with CHD?
Trisomy 21 (Down Syndrome).
What is the size of the ASD determined by?
Volume of shunting
What are the 3 types of ASDs and their locations?
- Sinus venosus (junction of the SVC + RA)
- Secundum (mid septum)
- Primum (low septum at the “crux”)
What’s the average adult’s CO?
4900 mL/min.
What is the tx for HF & FTT?
- Fluid restriction
- Diuretics
- ACE inhibitors
- O2
- Optimize nutrition (hypercaloric tube feeds)
- Coil occlude in catheter (NOT for sinus venosus)
- Surgical closure
What range would we expect an infant’s SV to fall into?
5-13 mL/beat.
Would we expect an infant to have a higher or lower HR compared to an adult?
Higher.
If there is a left to right shunt, that means there’s an increased ____ blood flow from re-circulation of ____ blood
pulmonary, oxygenated
What’s the equation for cardiac output?
CO= SV x HR
List 5 factors that affect CO (besides the ones in the equation).
- Body size/body surface area (BSA).
- Metabolic needs of tissues.
- Preload.
- Afterload.
- Contractility.
Would you be concerned if you heard 2 S2 heart sounds? Why might we see this?
It can be normal: the pulmonic valve may close slower than the aortic valve.
Can systolic or diastolic murmurs be benign? When would we classify them as such?
Only systolic - when the murmur disappears with position/respirations.
Diastolic murmurs are always concerning!
Patent ductus arteriosus (PDA) occurs in 2 phases:
- Functional closure (continuous contraction of the smooth muscle wall in the first 12h after birth).
- Cessation of PGE2 in the fetal period.
What is the tx if the ASD is restrictive?
None
Average CO for an infant?
~600 mL/min
Which 2 anatomical structures does a PDA allow blood to flow between?
Aorta > pulmonary arteries.
In a PDA, there is a ____ to ____ shunt.
Left to right.
List 3 factors that affect the amount of shunting in a PDA.
- PDA size & length.
- Pressure gradients between aorta (higher) and pulmonary arteries (lower).
- Changing vascular resistance from the transition to postnatal period (increasing SVR, decreasing PVR).
A PDA increases the _____ ______ [heart chamber] preload & output.
left ventricle.
List 6 s&s of a PDA.
- Pulmonary HTN.
- CHF.
- Increased work of breathing.
- Continuous murmur.
- Palpable thrill in LUSB (left upper sternal border) - d/t high LV output.
- Apneas in premature infants - d/t immature myelination.
