Peds Cardio Flashcards
At what day of gestation does the fetal heart begin pumping?
Day 22
In utero, why is blood shunted to bypass the lungs?
Fetal lungs are not yet functioning and have high resistance due to presence of fluid
Outline the steps to fetal circulation (poor oxygen blood to medium oxygen blood)
POB (poor oxygenated blood) Leaves via Umbilical Arteries (2) and goes to the placenta for oxygenation
HOB (high oxygenated blood) returns via Umbilical Vein - goes to fetal IVC and enters in the the Right Atrium.
Some of the HOB crosses to the LA via the Foramen Ovale.
The rest mixes with POB blood from the SVC = MOB (medium oxygen blood)
Outline the steps to fetal circulation (medium oxygen blood to placenta)
MOB blood enters the RV and exits via the Pulm trunk.
A portion of MOB bypasses the lungs –> Aorta via the Ductus Arteriosus
The remaining MOB is delivered to the lung and returns to the LA via the pulm veins. –> LV –> Aorta –> fetal tissue & back to placenta via umbilical arteries
Fetal vs. neonate structures: what does ductus arteriosus become after birth?
Ligamentum arteriosus
Fetal vs. neonate structures: what does foramen ovale become after birth?
Fossa ovalis
Fetal vs. neonate structures: what does umbilical vein become after birth?
Ligamentum teres
Fetal vs. neonate structures: what do umbilical arteries become after birth?
Medial umbilical ligaments
Newborn (and adult) blood circulation - right atrium to lungs
- Right atrium receives deoxygenated blood from SVC, IVC, and coronary sinus.
- Right atrium blood goes through tricuspid valve into right ventricle.
- Right ventricle blood goes through pulmonary valve into pulmonary trunk and pulmonary arteries.
- Blood in pulmonary capillaries loses CO2 and gains O2 (in the lungs).
Newborn (and adult) blood circulation - lungs to body
- Oxygenated blood goes from lungs through pulmonary veins into left atrium.
- Left atrium sends blood through bicuspid valve into left ventricle.
- Left ventricle sends blood through aortic valve into aorta and systemic arteries.
- In systemic capillaries, blood loses O2 and gains CO2 (in the body).
Heart murmurs in infants and children
- common finding on routine exam
- 50% are innocent murmurs
Innocent murmurs are due to…
turbulent blood flow at the origin of the great vessels
Innocent murmurs are easier to hear on children than adults due to…
- Thin chest wall in children
- More angulated great vessels in children
- More dynamic circulation in children
List 6 features of pathologic murmurs
- All diastolic murmurs***
- All pansystolic murmurs
- Late systolic murmurs
- Loud murmurs > 3/6
- Continuous murmurs
- Associated cardiac abnormalities
Acyanotic vs. cyanotic defects
Acyanotic defects = left to right shunting
Cyanotic defects = right to left shunting
What are the 2 causes of acyanotic congenital heart diseases?
- abnormal connections
2. abnormal valves/vessels
List acyanotic congenital heart diseases d/t abnormal connections (3)
- Ventricular septal defect (VSD)
- Atrial septal defect (ASD)
- Patent ductus arteriosus (PDA)
List acyanotic congenital heart diseases d/t abnormal valves/vessels (5)
- Pulmonary stenosis (PS)
- Aortic stenosis (AS)
- Coarctation of aorta
- Mitral stenosis
- Ebstein’s anomaly
What is the single MC congenital heart defect?
Ventricular septal defect (VSD)
Where do VSD defects occur?
can occur in both the membranous portion of the septum (most common) and the muscular portion
Pathophysiology of VSD
- If the VSD is large enough, it can lead to symptoms.
- This occurs since a large amount of blood goes from the LV to the RV, then back to the LV causing an abnormally large amount of blood to enter the LV.
- Over a long period of time, the LV and RV hypertrophies and systolic dysfunction may occur when the heart can no longer compensate.
Pathophysiology of atrial septal defect
- Abnormal flowing of blood between the atrium, allowing blood to flow from the left atria into the right atrium
- Results in RAE and RVE → CHF
- Pulmonary vascular changes occur after decades of this defect
- Blood vessels in the lungs become damaged by the extra pressure.
- May have atrial dysrhythmias
Pathophysiology of patent ductus arteriosus (left to right shunt)
- With a drop in pulmonary arterial pressure or increased aortic pressure, blood will flow through PDA.
- LEFT TO RIGHT SHUNT***
- Increased pulmonary blood flow may lead to pulmonary edema.
- Reduced blood flow to all postductal organs
- At risk for endocarditis and pulmonary vascular disease in later life
Pathophysiology of patent ductus arteriosus (right to left shunt)
- If pulmonary artery pressure rises above aortic pressure, blood will move in the other direction.
- RIGHT TO LEFT SHUNT***