Flashcards in Congenital Heart Defects Deck (61):
What is a congenital heart defect?
any abnormality of the heart or vessel that is present at birth.
What are the causes of congenital heart defects?
- genetic mutations (ex. trisomy 21).
- environmental factors (teratogens, rubella, gestational diabetes).
What is a MILD congenital heart defect?
affects a discrete chamber or region, but is compatible with embryologic maturation.
What is a MODERATE congenital heart defect?
produces clinically significant manifestations that appear shortly after birth with transitioning circulation.
What is a SEVER congenital heart defect?
incompatible with intrauterine survival
What is the incidence of congenital heart defects in the USA?
1% or 40,000 each year
**What are the 12 most common congenital heart defects?
(she said we must memorize)
3. pulmonary stenosis
5. Tetralogy of Fallot
6. Coarctation of the aorta
7. Atrioventricular septal defect (AVSD)
8. aortic stenosis
9. transposition of the great arteries
10. persistent truncus arteriosus
11. total anomalous pulmonary venous connection
12. tricuspid atresia
What are the 3 primary categories of congenital heart defects?
1. left-to-right shunts
2. right-to-left shunts
What is a left-to-right shunt?
abnormal channel that permits blood flow down a pressure gradient from the left (systemic) side to right (pulmonary) side.
What are the clinical characteristics of a left-to-right shunt?
- no initial cyanosis
- increased pulmonary blood flow and pressure that can lead to RV hypertrophy and atherosclerosis of pulmonary vasculature.
- medial hypertrophy and vasoconstriction of pulmonary arteries leading to vascular cell proliferation and obstructive intimal lesions.
What happens when pulmonary vascular resistance approaches systemic levels with a left-to-right shunt?
a right-to-left shunt will occur (late cyanosis)
What are the 4 defects that are left-to-right shunts?
(remember the 4 D's)
What is an atrial septal defect (ASD)?
an abnormal, fixed opening in the atrial septum that permits shunting of blood between the left and right atria.
What are the major ASD subtypes?
secundum (90%), primum, and sinus venosus
What are the clinical features of ASD?
- right sided overload (due to left-to-right shunt).
- increased pulmonary blood flow and pulmonic valve murmur.
- asymptomatic before age 30.
- low mortality
- can be corrected surgically.
What is a VSD?
incomplete closure of the ventricular septum that permits blood flow between the left and right ventricles.
*MOST common form of congenital heart defect and usually associated with other congenital heart defects.
What are the major VSD subtypes?
membranous (90%), and muscular
What are the clinical features of VSD?
- RV hypertrophy and pulmonary hypertension (due to left-to-right shunt).
- 50% close spontaneously.
- long-term effects= pulmonary vascular disease, shunt reversal, cyanosis and death.
- treat surgically.
What is a patent ductus arteriosus (PDA)?
incomplete closure of the ductus arteriosus after birth, permits blood flow between pulmonary artery to aorta.
- 90% are isolated, 10% are associated with other defect.
How can we maintain the PDA if it is needed in certain situations (other congenital defects like aortic valve atresia) that require the shunting of oxygenated blood?
What can cause a PDA during pregnancy?
pregnancies complicated by hypoxia and rubella
What are the clinical features of a PDA?
- initial left-to-right shunt with no cyanosis.
- harsh "machinery-like" murmur.
- asymptomatic at birth.
- volume and pressure overload produces obstructive changes in pulmonary arteries to reverse shunt after birth.
What is an atrioventricular septal defect (AVSD)?
failure of superior and inferior endocardial cushions to adequately fuse in AV canal, resulting in incomplete closure of the AV septum and malformation of AV valves.
What are the major subtypes of AVSD?
- partial AVSD= primum ASD + cleft anterior mitral valve leaflet.
- complete AVSD= common AV valve leads to volume overload hypertrophy.
AVSD is seen in 1/3 of this group of people?
What is a right-to-left shunt?
abnormal channel that permits blood flow down a pressure gradient from the right (pulmonary) side to the left (systemic) side.
What are the clinical characteristics of right-to-left shunts?
- cyanosis and hypoxemia due to admixture of deoxygenated pulmonary venous blood and systemic arterial blood (severe= finger and toe clubbing and polycythemia).
- brain abscesses and infarction due to peripheral emboli bypassing the lungs to enter systemic circulation (paradoxical embolism).
What are the 5 defects that are right-to-left shunts?
(remember the 5 T's)
1. Tetralogy of Fallot (TOF)
2. Transposition of the great arteries (TGA)
3. Truncus arteriosus (PTA)
4. Tricuspid atresia
5. Total anomalous pulmonary venous connection (TAPVC).
What os TOF?
- asymmetrical fusion of the bulbar and truncal ridges leads to unequal division of the truncus arteriosus and malalignment of the aortic and pulmonary valves.
- the heart is boot shaped
What are the 4 clinical features that make up TOF?
1. Pulmonary Stenosis
2. Right ventricular hypertrophy
3. Overriding aorta
On what does pulmonary blood flow depend in TOF?
PDA or bronchial collateral vessels.
Can people make it to adult hood with an unnoticed TOF?
What will determine the severity of TOF?
What are the 2 types of TOF?
1. Pink tetralogy= mild subpulmonary stenosis resembling VSD, (left-to-right shunt with no cyanosis; hence pink).
2. Classi TOF= severe subpulmonic stenosis (right-to-left shunt with cyanosis at birth, hypoplastic pulmonary arteries and enlarging aorta, worsening obstruction) This stenosis is actually protective against pressure overload.
What is transposition of the great arteries (TGA)?
abnormal formation of the truncal and aorticopulmonary setpa that causes ventriculoarterial discordance. The means that the aorta is arising from the RV and the pulmonary artery is arising from the LV.
Does transposition of the great arteries mean your vascular system is in series or parallel?
parallel now instead of series.
Is transposition of the great arteries (TGA) compatible with life?
No, unless a shunt is present. Infant's outcome is dependent upon degree of "mixing" of blood, magnitude of tissue hypoxia, and RV maintenance of systemic circulation.
Will there be a good or bad outcome of a TGA with VSD?
Will there be a good or bad outcome of a TGA with PFO (patent foramen ovale)?
helps, but is overall still a BAD outcome (requires surgery)
Will there be a good or bad outcome of a TGA with PDA?
Helps, but is overall still a BAD outcome (requires surgery).
What happens to the LV and RV, respectively over time if TGA is left untreated?
LV becomes atrophic and RV becomes hypertrophic
What is persistent truncus arteriosus?
failure of the truncal ridges and the aorticopulmonary septum to develop normally and divide the truncus arterosus into the aorta and pulmonary trunks.
*So you see a single artery for systemic, pulmonary, and coronary circulations.
What are the clinical features of persistent truncus arteriosus?
- associated VSD allows mixing via right-to-left shunt.
- systemic cyanosis
- increased pulmonary blood flow with potential pulmonary hypertension.
What is tricuspid atresia?
complete occlusion of the tricuspid orifice due to unequal division of the AV canal.
You will see an enlarged mitral valve and hypoplastic RV.
What are the clinical features of tricuspid atresia?
- right-to-left shunt via ASD, PFO or VSD.
- high mortality in first weeks of life.
What is total anomalous pulmonary venous return (TAPVC)?
failure of pulmonary veins to directly join the left atrium. All pulmonary veins empty into the right atrium or superior vena cava.
What are the clinical features of TAPVC?
- right-to-left shunt via ASD or PFO allowing pulmonary venous blood to enter LA.
- volume and pressure hypertrophy of right side with dilation.
- pulmonary trunk dilation
- hypoplastic LA, but normal LV
What will you see with the obstructive anomalies?
abnormal narrowing of chambers, valves, or blood vessels of the heart to impede blood flow. Either stenosis (narrowing) or atresia (complete obstruction).
What are the 3 congenital obstructive anomalies?
1. coarctation of the aorta
2. pulmonary stenosis and atresia
3. aortic stenosis and atresia
What is coarctation of the aorta?
narrowing of the aorta seen more in males than females., but females with turner syndrome have a higher incidence.
What are the 2 types of coarctation of the aorta?
1. Infantile= hypoplastic aortic arch proximal to PDA and distal to arch vessels. .
2. adult= ridgelike folding of aorta opposite closed DA and distal to arch vessels.
What are the clinical features of infantile coarctation of the aorta?
- unsaturated blood delivered via PDA to lower half of body.
- present at birth and requires surgical intervention.
What are the clinical features of adult coarctation of the aorta?
- asymptomatic in childhood
- hypertension in upper limbs
- hypotension in lower limbs
- notching near ribs on radiography
What causes pulmonary stenosis or atresia?
asymmetrical septation of the outflow tract by the truncoconal ridges, causing obstruction at the pulmonary valve.
What will you see with isolated pulmonary stenosis?
RV hypertrophy and post-stenotic PA dilation
Will you see RV hypertrophy and PA dilation with coexistent pulmonary stenosis (aka with other defect)?
What is required to maintain blood flow to the lungs in pulmonary atresia?
What is aortic stenosis or atresia?
asymmetrical septation of the outflow tract by the truncoconal ridges causing narrowing of the aortic valve at 3 locations: valvular, subvalvular, and supravalvular.
Will the cusps of the aortic valve often be hypoplastic in aortic stenosis?
What is required with severe aortic stenosis?