Congenital cardiac defects Flashcards
Clinical presentation of atrial septal defect
- Usually asymptomatic until adulthood
- Causes a left to right shunt
- Pulmonary blood flow may be 2-8x that of normal
- Murmur is present from excessive circulation through the pulmonary valve
- Generally well-tolerated. Discovered in 30s
- ASD closure prevents complications
- Low mortality
Pathogenesis of atrial septal defect
- Abnormal fixed openings in the atrial septum from incomplete tissue formation
- Allows communication of blood between sides
- Septum primum: sits posterior to the right and left atria. Ostium primum sits anteriorly
- Ostium secundum is a second posterior opening that develops
- Septum secundum grows but leaves the hole of the foramen ovale and eventually forms a flap of tissue that works as a valve over the foramen
- Once the baby is born this should close due to the increased pressure in the systemic circuit
Morphology of atrial septal defect
Secundum ASD: deficiency in the middle of the septum that isn’t associated with other defects. 90%
- Primum anomalies: develop next to the AV valves
- Sinus venous defects: near the entrance of the SVC
Left to right shunt
Clinical signs of a patent foramen ovale
- Generally closes by 2 y/o
- Unsealed flap can open if pressures become elevated
- Pulmonary HTN, bowel movements, coughing or sneezing can induce this
- Paradoxical embolism may occur due to the movement of the embolus through the hole
- Left to right
Clinical presentation of ventricular septal defects
children
- Clinical course depends on the size of defect and association with right sided defects
- Shunt reversal, cyanosis and death are possible
- Surgery is delayed to see if there will be a spontaneous closure
Pathogenesis of ventricular septal defect
Incomplete closure of the ventricular septum that allows blood to freely flow between chambers
Morphology of ventricular septal defect
-Classified based upon location
-Most the size of aortic valve orifice
-90% in region of membranous interventricular septum (membranous VSD)
-Infundibular VSD: occur below the pulmonary valve.
-Most of these are single but they could be multiple
Left to right
Clinical presentation of patent ductus arteriosus
- Ductus normally functionally closes after 1 to 2 days from decreased vascular resistances and PGE2
- Closure is often delayed in hypoxic infants
- Machinery-like murmur
- Usually asymptomatic at birth
- There is no cyanosis
- In general, should be closed as rapidly as possible
Pathogenesis of patent ductus arteriosus
-From the pulmonary artery to the aorta. In fetus allows blood to bypass the lungs
-After first few months it forms the ligamentum arteriosum
Left to right
Clinical presentation of tetralogy of Fallot
- Some untreated individuals can survive into adulthood
- Severity depends on how much subpulmonary stenosis there is
- If mild, there can be a pink tetralogy due to the lack of shunting
- Classic TOF has higher pressure in the right that produces shunting and cyanosis
- This gets worse with age because as the heart grows, the pulmonic orifice does not get larger
- Surgical fixture is possible but complicated
Pathogenesis of Tetralogy of Fallot
Four features: VSD, obstruction of right ventricular outflow, an aorta that overrides the VSD, and right ventricular hypertrophy
-Cause an anterosuperior displacement of the infundibular septum
Morphology of Tetralogy of Fallot
- Heart is enlarged and boot shaped from right ventricular hypertrophy
- VSD is large with aortic valve at superior border
- Pulmonary valvular stenosis determines how much shunting will occur
Right to left
Clinical presentation of transposition of great arteries
- Inadequate with life unless a septal defect is there
- Pts with a VSD many times have a stable shunt
- Most patients die within months unless surgical intervention has been taken
Pathogenesis of transposition of great arteries
-In this there are two separate closed loops
-The aorta arises anteriorly from the right ventricle
-Develops due to the abnormal formation of the truncal and aortopulmonary septa
-Right ventricular hypertrophy happens early due to it’s pumping of the systemic circulation
-Left ventricle becomes thin walled
right to left
Clinical presentation of tricuspid atresia
cyanosis at birth
Pathogenesis of tricuspid atresia
- Complete occlusion of the tricuspid valvular orifice
- Unequal division of the AV canal, mitral valve is larger than normal and the right ventricle is underdeveloped
- Circulation may be maintained due to right left shunting
Clinical presentation of coarctation of aorta
Males, females with turners
- Depends on the severity of the coarctation
- Coarctation with a PDA shows symptoms right after birth with cyanosis of the lower half of the body
- W/o a PDA the disease goes unnoticed until adulthood: HTN in the UE and weak pulses in the LE
- Rib notching is seen on X ray due to the development of collateral circulation
- Murmurs are present throughout systole. Palpable thrill may be present
Pathogenesis of coarctation of aorta
- Encroachment of the aortic lumen is variable
- May occur as a solitary defect
- 50% of cases have a bicuspid aortic valve
- May be associated with congenital aortic stenosis, ASD, VSD, mitral regurgitation, berry aneurysms
Morphology of coarctation of aorta
Concentric left ventricular hypertrophy is present
Infantile vs adult form of coarctation of aorta
- Infantile form: tubular hypoplasia of the aortic arch proximal to PDA
- Adult form: Ridgelike folding of the aorta opposite the closed ductus arteriosis
Clinical presentation of pulmonary stenosis and atresia
- Mild to severe
- Can be isolated or a part of TGA or TOF
- May be asymptomatic or require surgical intervention
Pathogenesis of pulmonary stenosis and atresia
-Obstruction at the pulmonary valve
Morphology of pulmonary stenosis and atresia
- Right ventricular hypertrophy
- Post-stenotic dilation of the pulmonary artery due to jetting of the blood
Clinical presentation of aortic stenosis and atresia
- Duct closure in the first week of life is fatal
- Subaortic stenosis is associated with a prominent systolic murmur and sometimes a thrill
- Mild stenosis may be treated with prophylactic abx and avoidance of strenuous activity but there is still a risk of sudden cardiac death
Pathogenesis of aortic stenosis and atresia
- Can occur at three locations: valvular, subvalvular, and supravalvular
- Ductus needs to be open in order for blood to pass to the system (hypoplastic left heart syndrome)
- supravalvular stenosis: luminal constriction associated with deletions of chromosome 7 and the genes for elastin. Williams-Beuren syndrome (hypercalcemia, cognitive anomalies, characteristic facial anomalies)
Morphology of aortic stenosis and atresia
-Valvular aortic stenosis: cusps may be hypoplastic, dysplastic, or abnormal
-In severe cases: hypoplasia of the left ventricle, dense porcelian-like left ventricular endocardial fibroelastosis
isolated lesion in 80% of cases
