Severson: Congenital Cardiovascular Abnormalities Flashcards
What is the etiology of congenital heart disease (CHD)?
Most defects arise from faulty embryogenesis during weeks 3-8
What percent of CHD is genetic, environmental, unknown?
genetic-9%
environmental- 1%
Unknown- 90%
What are gene defects and chromosome defects related to CHD?
Gene- marfan syndrome 2-3%, familial
Chromosome- 5% (gametogenic, non familial)
What environmentally can cause CHD?
Rubella Chemical (thalidomide, ETOH)
What is the main pathopysiologic feature of CHD?
Shunt= abnormal communication leads to blood flow diversions
What causes left to right shunts? What is observed clinically in a baby with L to R shunts?
- atrial septal defect
- ventricular septal defect
- patent ductus arteriosus
Cyanosis several months or years after birth.
What causes right to left shunts? What is observed clinically in a baby with R to L shunts?
- tetralogy of fallot
- transpositon of hte great arteries
- truncus arteriosus (persistant)
Cyanosis early in postnatal life
What causes cyanosis?
Oxygen saturation below 75%
What type of cyanosis is observed w/ R to L shunts vs L to R shunts?
- right to left shunts- cyanosis
2. left to right- no cyanosis or cyanosis tardive
What is normal pulmonary artery/aorta pressure?
How do shunts affect pressure?
1/6
Increased right ventricular or pulmonary artery pressure leads to lung fibrosis. Late right ventricular failure may lead to reversed flow (ventricular septal defect)
What type of obstructions can lead to CHD?
Stenosis or atresia. Stressed ventricles lead to ventricular failure and may require shunts for survival.
What is an ASD (atrial septal defect)?
An abnormal opening between the right and left atria. Normally a R to L shunt is open in fetus but is closed in adults.
What causes an ASD abnormality?
Incorrect development of the atrial septum.
What are the four ways incorrect development of the atrial septum can occur?
- Excessive resorption of the primary septum)
- Incompetent foramen ovale d/t hypoplastic growth of the secondary septum
- inadequate development of hte primary septum producing a basal opening known as a primary foramen defect
- Sinus venosus developmental defect
What happens in an atrial septal defect?
Left to right shunting of blood
How does ASD affect the blood flow of the heart?
Pulmonary blood flow may be 2-4 ties normal. It tends to be size dependent, only large ones lead to pulmonary hypertension with cyanosis tardive or cardiac failure.
What complications can occur with ASD?
- Right ventricular failure
2. paradoxical embolism (and brain infarction/abscess)
What is the RX for ASD?
Surfery, if large to close the ASD (patch foramen)
What is the most common congenital heart abnormality?
VSD- ventricular septal defect (40%)
Symptoms that result from VSD are dependent on….
SIZE of the defect
What is a solitary VSD?
90% involve the membranous portion of the ventricular septum
What other abnormalities are often observed with VSD?
pulmonary stenosis, tetralogy of fallot, coarctation of aorta, transposition of the aorta
What is seen in long standing cases of VSD?
Cyanosis tardive
What percent of VSD close spontaneously?
50%
What is the RX for VSD?
surgery
What is a PDA (patent ductus arteriosus?
A defect that directs blood from the pulmonary artery to the aorta during fetal life
What happens normally to the DA and what happens in PDA?
Normally, flow decreases on Day 1, with the ligamentous structure forming on Day 30.
If the ducturs remains patent after birth, the direction of blood flow is from aorta to the pulmonary artery. Reversed blood flow causes cardiac enlargement and increased pulmonary vascularity.
PDA is often associated with what illness during the early weeks of pregnancy?
Maternal rubella (german measles)
What other defects are associated with maternal rubella?
- Congenital cataracts
2. deafness
What type of murmur is heard with PDA?
Machinery like murmur “thrill”
What clinical complications often occur with PDA?
- infective endocarditis
2. pulmonary hypertension
What is the Rx for PDA?
Surgery
cardiologist: catheter placed ocluder
Medical: ibuprofen in prematures
What is tetralogy of fallot (TF)?
Most common form of cyanotic heart disease
What defects are commonly seen w/ TF?
- ventricular septal defect
- pulmonary stenosis
- overriding (large) aorta
- Right ventricular hypertrophy
What is observed clinically with TF?
- Cyanosis dependent on the size of ventricualr septal defect; may be absent early.
- murmur d/t pulmonary stenosis.
What complications can occur with TF?
Paradoxical embolism (brain abscess) Infective endocardidtis
What Rx is used for TF?
surgery
What are the three types of right left shunts?
The three T’s!
Tetralogy of fallot
Transposition of the great arteries
Truncus arteriosus
What is transposition of the great arteries?
When there is a straight division of the bulbus cordis and truncus arteriosus d/t a FAILURE in the normal spiraling of the AORTICOPULMONARY SEPTUM. Because of this the aorta originates from the right ventricle and the pulmonary artery comes from the left ventricle.
Is TGA compatible w/ life?
Sadly no, unless you also have an atrial and ventricular septal defect present as well as a patent ductus arteriosus.
Is TGA more common in M or F?
M 3:1
What defect is particularly common in diabetic mothers?
TGA
What is the RX for TGA?
Early surgery
What is Truncus arteriosus?
Failure of the bulbar and truncal ridges (aorticopulmonary septum) to develop. This creates a common aorticopulmonary outlet that receives blood from both ventricles.
What is a common SE of truncus arteriosus?
Since there is mixing of the blood CYANOSIS is present, and there is an increased pulmonary blood flow leading to irreversible pulmonary hyperplasia.
What is coarctation of the aorta?
An obstructive congenital heart defect caused by infolding of the aorta opposite the closed ductus arteriosus that leads to constriction of the aorta just distal to the ligamentum arteriosum.
Which type of coarctation, postductal or preductal is the adult form? Is it more common in M or F?
Postductal
Common 95%, twice as common in males as F
How does postductal Coarctation of the aorta effect blood pressure in the extremities?
It INCREASES (hypertension) in the arms and DECREASES (weak pulse and low BP) in the legs.
What congenital defect is associated with notched ribs?
Postductal Coarctation of the aorta
Enlarged intercostal and internal thoracic arteries leads to notched ribs.
In what percentage of cases is postductal coarctation of the aorta accompanied by a bicuspid aortic valve?
50%
What complications are associated with postductal coarctation of the aorta?
CHF, cerebrovascualr accidents, rupture, infection
What is the RX for postductal coarctation of the aorta?
Excision, bypass, balloon angioplasty
What is preductal coarctation of the aorta?
INFANT FORM
Narrowing of the aortic segment between the left subclavian artery and the ductus arteriosus.
Preductal coarctation of the aorta has what SE?
- Early CHF d/t hypertrophy of hte right ventricle
- Cyanosis in lower half of the body
- Increased mortality
What developmental structure is responsible for the occurance of either pulmonary or aortic stenosis?/
Defective development of the aorticopulmonary septum (bulbar truncal ridges)
What shunts are characteristic of early cyanosis = blue babies?
R to L shunts (aorticopulmonary septum)
Tetralogy of fallot
Transpositoin of great arteries
truncus arteriosus
What shunts are characteristic of late cyanosis =blue kids?
Ventricular septal defect
atrial septal defect
patent ductus arteriosus
What is the difference between pre and postductal coarctation of the aorta?
Postductal- BP higher in upper extremity than lower
Preductal- patent ductus arteriosus and cyanosis in lower body
What defect is associated with maternal diabetes?
TGA
What defect is associated with maternal rubella?
PDA- patent ductus arteriosus
PS- pulmonary stenosis
VSD-ventricular septal defect
What defects are associated with DiGeorge syndrome?
Tetralogy of fallot
truncus arteriosus
What defects are associated with down syndrome?
atrial septal defect
ventricular septal defect
What defect is associated with turner syndrome?
coarctation of the aorta
What defect is associated with marfan syndrome?
aortic stenosis