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