Congenital cardiac defects

Question 1

Clinical presentation of atrial septal defect

Answer 1

• 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

Question 2

Pathogenesis of atrial septal defect

Answer 2

• 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

Question 3

Morphology of atrial septal defect

Answer 3

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

Question 4

Clinical signs of a patent foramen ovale

Answer 4

• 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

Question 5

Clinical presentation of ventricular septal defects

Answer 5

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

Question 6

Pathogenesis of ventricular septal defect

Answer 6

Incomplete closure of the ventricular septum that allows blood to freely flow between chambers

Question 7

Morphology of ventricular septal defect

Answer 7

-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

Question 8

Clinical presentation of patent ductus arteriosus

Answer 8

• 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

Question 9

Pathogenesis of patent ductus arteriosus

Answer 9

-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

Question 10

Clinical presentation of tetralogy of Fallot

Answer 10

• 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

Question 11

Pathogenesis of Tetralogy of Fallot

Answer 11

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

Question 12

Morphology of Tetralogy of Fallot

Answer 12

• 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

Question 13

Clinical presentation of transposition of great arteries

Answer 13

• 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

Question 14

Pathogenesis of transposition of great arteries

Answer 14

-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

Question 15

Clinical presentation of tricuspid atresia

Answer 15

cyanosis at birth

Question 16

Pathogenesis of tricuspid atresia

Answer 16

• 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

Question 17

Clinical presentation of coarctation of aorta

Answer 17

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

Question 18

Pathogenesis of coarctation of aorta

Answer 18

• 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

Question 19

Morphology of coarctation of aorta

Answer 19

Concentric left ventricular hypertrophy is present

Question 20

Infantile vs adult form of coarctation of aorta

Answer 20

1. Infantile form: tubular hypoplasia of the aortic arch proximal to PDA
2. Adult form: Ridgelike folding of the aorta opposite the closed ductus arteriosis

Question 21

Clinical presentation of pulmonary stenosis and atresia

Answer 21

• Mild to severe
• Can be isolated or a part of TGA or TOF
• May be asymptomatic or require surgical intervention

Question 22

Pathogenesis of pulmonary stenosis and atresia

Answer 22

-Obstruction at the pulmonary valve

Question 23

Morphology of pulmonary stenosis and atresia

Answer 23

• Right ventricular hypertrophy

- Post-stenotic dilation of the pulmonary artery due to jetting of the blood

Question 24

Clinical presentation of aortic stenosis and atresia

Answer 24

• 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

Question 25

Pathogenesis of aortic stenosis and atresia

Answer 25

• 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)

Question 26

Morphology of aortic stenosis and atresia

Answer 26

-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