Congenital Heart Disease Flashcards
What type of shunt is present in CHF?
left to right shunt
T or F: fetal physiology allows for many CHD that would otherwise be incompatible with life as neonate
T
What two things in fetal cardiac physiology that allows for CHD?
Placental oxygenation
The patent ductus arteriosus (PDA)
What happens to the O2 sat at RV in ASD?
Saturation increases in RV due to blood mixing in RA, and RV hypertrophy occurs due to increased chronic preload.
What happens in muscular VSDs?
LA and LV hypertrophy (dilated)
pulmonary overcirculation
Where does patent ductus arteriosus occur and results to what type of shunt?
Aortic arch
left-to-right (aorta to pda)
T or F: left-to-right shunt is CHF
T
When is CHF usually presented in babies?
2-6 weeks
What are signs of CHF in babies?
- Tachypnea and dyspnea
Pulmonary overcirculation and pulmonary edema from increased capillary hydrostatic pressure - Tachycardia
Increased sympathetic output with chronotropic and inotropic response - Diaphoresis
Increased sympathetic tone and WOB - Hepatomegaly
Systemic venous congestion and intra-vascular volume increase - Failure to thrive
Feeding difficulties due to increased work of breathing and fatigue
Significant caloric expenditure by the persistent tachypnea and tachycardia
What can cause central cyanosis?
Structural heart disease or Lung disease
What happens in aortic coarctation?
Concentric LV hypertrophy, low pressure at thoracic aorta but high pressure before coarctation
What is the treatment for aortic coarctation?
Balloon dilation treatment
What is the pulmonary vascular transition?
The changes in vasculature, pressure, flow, and resistance.
In fetus, pulmonary arteries have a thick intima of muscles that make them stiff –> high pressure
There is a sharp decrease in PVR and PMAP at birth and continues to drop gradually after birth (due to loss of muscle and compliant arteries); PBF increases
What is usually the saturation of the blood at the right heart?
70%
What are the three types of left heart obstructive lesions?
- Sub AS (below the aortic valve)
- Supra AS (above)
- HLHS (hypoplastic left heart syndrome)
How to calculated shunt ratio?
Qs/Qt = (CcO2 + CaO2) / (CcO2 + CvO2)
where
Qs/Qt = shunt fraction (shunt flow divided by total cardiac output)
CcO2 = pulmonary end-capillary O2 content, same as alveolar O2 content
CaO2 = O2 content from venous return
CvO2 = mixed venous O2 content
What are the common acyanotic CHDs?
- ASD (l to r)
- VSD (l to r)
- Patent foramen ovale (PFO)
- Patent ductus arteriosus (PDA) [l to r]
- Coarctation of the aorta
What are common cyanotic CHDs [ie. usually structural heart defects]?
- ToF
- TGV
- Hypoplastic left heart syndrome
- Tricuspid valve atresia
- Ebstein Anomaly
What are the features of ToF?
- VSD
- Overriding aorta
- RV hypertrophy
- Pulmonary stenosis
What is the treatment for tet spell?
- knee to chest position
- O2 (decreases pulmonary resistance)
- beta blockers (relax RVOT)
What occurs in truncus arteriosus?
Aortic and pulmonary trunk fused together
- almost always a VSD present
What is usually associated with TGA?
maternal diabetes
What is the treatment of TGA?
Keep PDA open with alprostadil (prostaglandin) until surgery and make a ASD
What happens in Tricuspid Atresia?
No tricuspid valve, RA and RV blocked from each other, and RV and LV connected so:
Blood from RA –> LA via PFP/ASD –> LV –> some goes back to RV via VSD
Blood going to aorta –> some go through PDA
What is the most common congenital anomaly?
VSD associated FSD
What kind of murmur is heard for VSD?
Harsh holosystolic at the tricuspid area (LLSB at 4 th ICS)
What kind heart sound is seen in ASD?
Fixed splitting of S2
Why large ASDs require surgical patching?
Prevent pulmonary HTN and pulmonary atery hypertrophy
What kind of cyanosis occurs in PDA?
differential (ie. blue toes, but normal fingers)
T or F: widened pulse is seen in PDA
true
Whats Eisenmenger’s Syndrome?
Uncorrected ASD, VSD, PDA that switches shunting from l to r –> r to l
–> results in cyanosis, clubbing, polycythemia, RVH
What birth defect is associated Down syndrome?
VSD
What is the PDA’s function in fetal life?
To divert blood to aorta to prevent it going to lungs (i.e. blood from mother and does not require oxygenation)
In shunts associated with heart failure, what is the direction of blood flow?
left to right (commonly ASD)
What should the saturation of blood be from RA, RV, and pulmonary trunk?
70%
T or F: there is a saturation step up in ASD
True
What would a big RV with respect with a ASD signify?
Big ASD
When would small ASD patients present?
usually adulthood
What kind of VSDs are more common?
membranous VSDs
If we have a same size VSD and ASD, which one would have more flow from left to right?
VSD because pressure difference is higher
Why does the LA and LV enlarge with a large VSD?
Because there is more blood going to right side which is then added to the volume already present in LA and LV (so check for size)
RV does not dilate because it is momentarily overloaded during systole (LV blood flows directly through pulmonary valve
For a large VSD, why blood flow left to right despite the pressures being the same between L and R ventricles?
Because pulmonary resistance lower than systemic
T or F: the step up in saturation is greater in large VSD
T:
and also bigger left heart dilation
When would you expect congestive heart failure with VSD?
2-6 weeks
What are the classic symptoms of VSD with heart failure?
Tachypnea and dyspnea
- Pulmonary overcirculation and pulmonary edema from increased capillary hydrostatic pressure
Tachycardia
- Increased sympathetic output with chronotropic and inotropic response
Diaphoresis
- Increased sympathetic tone and WOB (especially during feeding)
Hepatomegaly
- Systemic venous congestion and intra-vascular volume increase
Failure to thrive
- Feeding difficulties due to increased work of breathing and fatigue
- Significant caloric expenditure by the persistent tachypnea and tachycardia
What would a right to left shunt usually cause?
central cyanosis without associated respiratory distress
What is the worst right to left shunt?
TGA (child dies in hours of birth)
What is the initial therapy for TGA?
Initial stabilization:
- prostaglandin to allow blood from aorta (low O2) to go to pulmonary artery (high O2)
- atrioseptal hole to allow mixing of high oxygenated blood to right side for pumping (ie ASD)
Where do most co-arctations occur in the aorta?
Near the PDA
What is coarctation of the aorta associated with?
Turner’s Syndrome
Why does the heart go through concentric hypertrophy in coarctation?
Because there is an increase in pressure in the ascending aorta
What heart defect is common in Williams’ syndrome?
Supra- Aortic stenosis
