congenital heart disease

What is the first organ system to become functional?

Cardiovascular system.

Most sensitive period for cardiac development?

3–6 weeks.

When does the primitive heart begin beating?

About 22 days.

When does septation begin?

33–37 days.

By what day is the fetal heart a complete complex structure?

43 days.

What are the layers of the primitive heart tube?

Endocardium, cardiac jelly, myocardium.

Why does the heart tube loop?

The tube becomes too long for the pericardial cavity.

By day 28 where does the loop point?

Forward and to the right.

Why is looping important?

Places atria behind and above ventricles.

What does the AV canal eventually form?

Tricuspid and mitral valve openings.

What does the left horn of the sinus venosus become?

Coronary sinus.

What does the right horn of the sinus venosus become?

Sinus venarum of the right atrium.

Primitive atrium develops into what?

Right and left atria.

Primitive ventricle develops into what?

Left ventricle.

Bulbus cordis develops into what?

Right ventricle.

Conus develops into what?

Crista supraventricular.

Truncus arteriosus develops into what?

Aorta and pulmonic valves.

What forms first in atrial septation?

Septum primum.

What is the ostium primum?

Opening before septum primum closes.

What forms after ostium primum closes?

Ostium secundum.

What is the septum secundum?

Second thicker wall next to septum primum.

What opening remains after septum secundum forms?

Foramen ovale.

Why is the foramen ovale important?

Allows blood to bypass fetal lungs.

What does the foramen ovale become after birth?

Fossa ovalis.

What structures divide the AV canal?

Endocardial cushions.

What does the right AV canal become?

Tricuspid valve opening.

What does the left AV canal become?

Mitral valve opening.

What forms the future wall between ventricles?

Primitive interventricular septum.

What is the interventricular foramen?

Opening between RV and LV before septum closes.

What closes the interventricular foramen?

Bulbar ridges, endocardial cushions, muscular septum.

Which embryologic aortic arch remains (persists) to form a specific adult structure?

During development, there are 6 pairs of aortic arches, and each one either:

• persists (stays and becomes an adult structure), or

• regresses (disappears)

3rd → ICA, 4th → aortic arch, 6th → pulmonary arteries.

Which aortic arches disappear?

1st, 2nd, and 5th.

What forms the aorticopulmonary septum?

Bulbar ridges.

What does the aorticopulmonary septum separate?

Aorta and pulmonary artery.

What are the semilunar valves?

Aortic and pulmonary valves.

What are the AV valves?

Mitral and tricuspid valves.

What do chordae tendineae do?

Prevent valves from flipping backward.

Where does fetal oxygenation occur?

Placenta.

What are the 3 fetal shunts?

Ductus venosus, foramen ovale, ductus arteriosus.

What does the ductus venosus do?

Bypasses liver.

What does the foramen ovale do?

Shunts blood from RA to LA.

What does the ductus arteriosus do?

Bypasses lungs into descending aorta.

What does the foramen ovale become after birth?

Fossa ovalis.

What does the ductus arteriosus become after birth?

Ligamentum arteriosum.

What does the ductus venosus become after birth?

Ligamentum venosum.

Which side of the heart normally has higher pressure after birth?

Left side.

ASD/VSD after birth usually shunt which direction?

Left to right.

What are the 3 types of ASD?

Ostium primum, ostium secundum, sinus venosus.

Where is ostium primum ASD located?

Lower septum by AV valves.

Where is ostium secundum ASD located?

Central septum.

Where is sinus venosus ASD located?

Superior interatrial septum.

What are the 4 types of VSD?

Perimembranous, inlet, subarterial, muscular.

Most common VSD? (ventricular septal defect)

Perimembranous.

What is patent ductus arteriosus?

Blood leaving the aorta is shunted back to pulmonary artery.

PDA can cause what?

LV volume overload.

What happens in Ebstein’s anomaly?

Tricuspid leaflets are displaced apically.

What happens to the RV in Ebstein’s anomaly?

RV becomes smaller.

What does ARV stand for?

Atrialized RV.

What does FRV stand for?

Functional RV.

What are the 4 defects in Tetralogy of Fallot?

VSD, overriding aorta, pulmonary stenosis, RV hypertrophy.

What abnormalities are listed under abnormal vasculature?

Aortic stenosis, pulmonic stenosis, patent foramen ovale.

Left-to-right shunting can cause what?

Right-sided enlargement.

Other names for endocardial cushion defect?

AV canal defect, AV septal defect.

What does a partial endocardial cushion defect include?

Ostium primum ASD and cleft mitral valve.

What does a complete endocardial cushion defect include?

ASD, VSD, common AV valve.

What is coarctation of the aorta?

Narrowing of the aorta.

Where does coarctation usually occur?

Near origin of left subclavian artery.

What are the two types of coarctation?

Preductal and postductal.

What happens in transposition of great arteries (TGA)?

Aorta comes from RV and pulmonary artery comes from LV.

What is Eisenmenger syndrome?

Long-term ASD/VSD causes pulmonary hypertension and reverses shunt direction.

What happens to the shunt direction in Eisenmenger syndrome?

Left-to-right becomes right-to-left.

What enters systemic circulation in Eisenmenger syndrome?

Deoxygenated blood.