congenital cardiovascular disease Flashcards
(92 cards)
1
Q
how does the placenta carry blood to the foetus?
A
through the umbilical vein
2
Q
where is 25% of blood diverted to in the feotus?
- where will the rest go?
A
the ductus venosis
- the remainder will be distributed to the liver via the portal vein and he hepatic portal system
3
Q
what is the ductus venosus critical for?
A
delivering well-oxygenated blood to the left side of the foetal heart and thus to the coronary and cerebral circulation
4
Q
what prevents a major portion of the cardiac output from entering the lungs?
A
high pulmonary vascular resistance in the foetus will prevent a major portion of the cardiac output from entering the lungs
- blood flow will be diverted to other organs via the Formen oval and the ductus arteriosus
5
Q
describe the transition from neonatal to normal circulation?
A
- first breathe, pulmonary vascular resistance drops
- this reduced resistance results in increased flow through the pulmonary arteries
- causing an increase in pressure in the left atria and the abrupt reduction in the pressure on the right side of the heart.
- formane ovale closure
- blod no longer bypasses the pulmonary circulation
6
Q
what are congenital heart defects?
A
- they are problems with the hearts structure that are present at birth
- they change the normal flow of blood through the heart
7
Q
what percentage of live births have CHD?
A
0.8%
8
Q
3 main types of CHD?
A
1- the interior walls of the heart
2- the valves inside the heart
3- the arteries and veins that carry blood to the heart or away from the heart to the body.
9
Q
6 types of acyanotic CHD?
A
1- ventricular septal defect
2- atrial septal defect
3- pulmonary stenosis
4- aortic stenosis
5- correction of the aorta
6- patent ductus arteriosus
10
Q
what are the 5 T’S for cyanotic CHD?
A
1- Tetralogy of Fallot
2- Total anomalous pulmonary venous return
3- Transposition of the great vessels
4- Tricuspid atresia
5- Truncus arteriosus
11
Q
what are 2 other types of cyanotic CHD?
A
- hypoplastic left heart
- pulmonary atresia
12
Q
3 examples of left to right shunts?
A
1- ventricular septal defect
2- atrial septal defect
3- patent ductus arteriosus
13
Q
left to right shunts?
A
these are lesions that allow blood to shunt from the left to the right side of the heart
- they are associated with varying degrees of increased pulmonary blood flow and are typical acyanotic
- doesn’t eff t the proces of oxygenation in your lungs
14
Q
examples of right to left shunts?
A
1- tetralogy of Fallot
2- transposition of the great arteries
3- pulmonary valve atresia
4- truncus arteriosus
5- tricuspid atresia
6- total anomalous pulmonary venous return
15
Q
right to left shunt?
A
lesions that result in deoxygenated blood reaching the aorta.
16
Q
examples of obstructive valvular and non valvular lesions?
A
- coarction of the aorta
- pulmonary valve stenosis
- aortic valve stenosis
17
Q
what is the most common congenital heart defect?
A
ventricular septal defects
18
Q
describe ventricular septal defects
A
- 20% of cases
- subtypes based on location of the defect
- small medium or large
19
Q
what is the difference between small, medium and large ventricular septal defects?
A
small = don’t cause problems and may close on their own
medium = less likely to close on their own and may require treatment
large = allow a lot of blood to flow from the left to the right ventricle. this extra blood increase blood pressure in the right side of the heart and the lungs
20
Q
if there is a larger ventricular septal defect, what signs of excess pulmonary blood flow may they experience?
A
- tachypnoea
- tachycardia
- pallor
- poor feeding
- poor weight gain
21
Q
what happens if the whole doesn’t close in ventricular septal defect?
A
(the extra workload can cause heart failure and poor growth)
- if the whole doesn’t close, high blood pressure can scar the arteries in the lungs leading to pulmonary hypertension and irreversible damage causing shunt reversal and EISENMEGEsyndrome.
22
Q
clinical signs of Ventricular septal defect?
A
- pan systolic murmur
- loud second heart sound
- heart failure
23
Q
what clinical findings would you expect to see for ventricular septal defect?
A
- cardiac enlargement
- increased pulmonary vascular markings (CXR)
- left ventricle hypertrophy (ECG)
- an echo will show the defect itself.
24
Q
how can you repair a medium/large ventricular septal defect?
A
- can be repaired using a catheter or open heart surgery
- large = diuretics and increased calories followed by closure
25
describe Patent Ductus arteriosus?
- 9 to 12% of all CHD
- 30 fold higher incidence in patients born in a higher altitude
26
what is PDA/
- persistent communication between the descending thoracic aorta and the pulmonary artery that results from failure of normal physiological closure of the foetal ductus.
- left to right shunt, the blood flows from the aorta to the pulmonary aorta
27
why is there a continuous murmur in PDA?
- as the pressure in the pulmonary artery is lower than in the aorta throughout the cardiac cycle
- this murmur is continuous because the thoracic pressure if higher than the pulmonary artery pressure during both systole and diastole.
28
what would you see in the clinical tests for PDA?
- ECG and CXR will be normal
- in a large PDA, you will see biventricular hypertrophy on the surface ECG
- in a large PDA, you will see increased pulmonary blood flow and cardiomegaly on CXR may be present
- echocardiograpghy allows delineation of the PDA anatomy and the direction and the volume of the shunt.
29
how to treat PDA in a newborn?
if there is significant respiratory distress or impaired systemic oxygen delivery, treat with intravenous indomethacin or ibuprofen
30
how to treat PDA in older children?
closure is recommended to avoid the risk of infective endocarditis, options are catheter closure or surgical ligation.
31
describe arterial septal defect?
- 6-10% (4 subtypes based on location of the defect)
- can be small, medium or large
32
small atrial septal defect?
allow only a little blood to leak from one atrium to the other
- they don't effect how the heart works
- close on their own
33
medium and large atrial septal defects?
- allow more blood to leak from one atrium to the other
- don't close on their own
34
if untreated what happens in ASD?
- leads to exercise intolerance and atrial arrhythmias in the third or fourth decade of life.
- people are often asymptomatic and this is the most commonly missed diagnosis
35
what are signs of ASD?
- no symptoms/ recurrent chest pain
- in moderate to large lesions:
= ejection systolic murmur
this murmur will be caused by increased blood flow through the pulmonary valve, not through the ASD
36
in ASD, what would the clinical signs be?
- CXR = normal
- ECG= normal (except in a larger lesion, there may be right atrial enlargement, right ventricular enlargement or right axis deviation)
37
how to treat ASD?
medium and large ASD's:
operation or percutaneous devise closure.
38
what are the 4 defects in tetralogy of fallout (TOF) ?
- pulmonary valve stenosis or right ventricular outlet obstruction (RVOT)
- a large ventricular septal defect (VSD)
- an overriding aorta
- right ventricular hypertrophy (due to RVOT)
39
what happens as a result of an overriding aorta?
oxygen poor blood from the right ventricle can flow directly into the aorta instead of the pulmonary artery
40
most patients with TOF will have what?
progressive cyanosis after birth followed by dyspnoea on exertion as a child.
- faltering growth
41
what are the hypoxic episodes or 'tet spells' in TOF?
they consist of an abrupt onset of rapid shallow breathing
- increased agitation
- cyanosis
- decrease in murmur intensity due to reduced blood flow through the RVOT
42
WHAT DO older children with TOF do when they have hypoxic spells?
they will squat to increase systemic vascular resistance and thereby reduce hypoxaemia.
43
how do you diagnose TOF?
- antenatally
- following the identification of a murmur in the first 2 months of life
- cyanosis may not be apparent at the beginning but it will develop
- a loud ejection systolic murmur is heard at the left upper sternal border with radiation to both axillae due to the RVOT obstruction.
44
infants who are very cyanosed in the early neonatal period require a shunt to increase pulmonary blood flow, how is this done?
surgical placement of an artificial tube between the subclavian artery and the pulmonary artery (a modified blalock-taussig shunt)
45
how does a modified blalock-tausing shunt work?
it will redirect a large portion of partially oxygenated blood leaving the heart for the body into the lungs, increasing flow through the pulmonary circuit and greatly relieving symptoms in patients.
46
how does the surgery for TOF work?
it involves closing the VSD and relieving right ventricular outflow tract obstruction, sometimes with an artificial patch which extends across the pulmonary valve
- the timing of the surgery will depend on how narrow the pulmonary artery is.
47
what is transposition of the great arteries?
when the pulmonary arteries are supplied by the left ventricle and the aorta by the right ventricle (which is opposite to norm) - deoxygenated blood is moving around the body
48
how can an infant survive transposition of the great vessels?
infants can only survive if there is a shunt between the two sides of the heart.
some naturally occurring anomalies can also achieve this mixing. (VSD, ASD and PDA)
49
symptoms of transposition of the great arteries?
- cyanosis is always resent
- the second heart sound is often loud and single
- usually there is no murmur
50
how do you treat transposition of the great vessels?
- maintaining the potency of the ductus arteriousus with a prostaglandin infusion is mandatory
- a balloon atrial septostomy
- patients almost always need an atrial switch procedure
51
how does a ballon atrial septostomy work?
a catheter with an inflatable balloon at its tip will be passed through the umbilical cord or femoral vein and then through the right atrium or foramen vale.
- the balloon will then be inflated within the left atrium and then pulled back through the atrial septum. this tears the atrial septum, renders the valve of the Forman oval incompetent and allows the mixing of the syetmi and pulmonary venous blood within the atrium.
52
what is an atrial switch procedure?
the pulmonary artery and the aorta are transected above the arterial valves and switched over.
53
what is an atrioventricular septal defect? (AVSD)
this is. heart defect in which there are holes between the chambers of the right and left side of the heart, and the valves that control blood flow between these chambers may not be formed correctly.
54
what is AVSD also known as?
atrioventricular canal or endocardial cushion defect.
55
amongst who is AVSD common?
babies with Down syndrome
56
2 clinical presentation signs of AVSD?
1- antenatal ultrasound screening or routine echocardiography screening in a newborn infant with downs.
2- cyanosis at birth or heart failure at two weeks to 3 weeks of life
no murmur heard.
57
management of AVSD?
treat heart failure medically (as for large VSD) and a surgical repair at 3 months to 6 months of age.
58
atresia?
- this defect occurs if a valve doesn't form correctly and lacks a whole for blood to pass through.
- atresia of a valve generally results in more complex congenital heart disease
59
stenosis?
- this defect occurs if the flaps of a valve thiken, stiffen or fuse. as a result, the valve cannot fully open. thus the heart must work harder to pump blood through the valve.
60
regurgitation?
this defect occurs if a valve doesn't close tightly, as a result, blood leaks back through the valve.
61
what are 3 CHD affecting the valves inside the heart?
- stenosis
- atresia
- regurgitation
62
what are 3 lesion causes of obstruction in the well child?
aortic stenosis
pulmonary stenosis
coarction
63
signs and management of aortic stenosis?
signs = murmur in the upper right sternal edge, carotid thrill
management = balloon dilation
64
signs and management of pulmonary stenosis?
signs = murmur in the upper left sternal edge, no carotid thrill
management = balloon dilation
65
signs and management of coarction ( mild, may be present in adolescence)?
signs = systemic hypertension or radiofemoral delay
management = stent insertion or surgery
66
describe pulmonary valve stenosis?
- most common valave defect
- narrowing of the pulmonary valve
- this valave is supposed to let blood flow from the right ventricle to the pulmonary artery
- flow will be smaller and slower than normal
67
do children tend to show signs of pulmonary valve stenosis?
most children will show no signs of pulmonary valve stenosis other than a heart murmur
treatment won't be needed if it is mild.
68
where should you listen for heart sounds for pulmonary valve stenosis?
- the ejection systolic murmur will best be heard at the upper left sternal edge
69
what may a small number of neonates with critical pulmonary valve stenosis show?
they may have duct dependant pulmonary circulation and present in the first few days with cyanosis
70
what may happen in babies with severe pulmonary valve stenosis?
the right ventricle can get over worked trying to pump blood to the pulmonary artery
- these babies may show signs of heart failure.
71
what may an ECG of pulmonary valve stenosis show?
right axis deviation
72
what may a CXR of pulmonary valve stenosis show?
right ventricular enlargement.
73
most used treatment of pulmonary valve stenosis?
catheter procedure or ballon dilation in children
74
describe aortic valve stenosis?
- 5%
- one of the 4 subtypes of left ventricular outlet obstruction
- results from minor to severe degrees of aortic valve maldevelopment or thickening.
75
presentation of aortic valve stenosis?
- presentation depends on the severity of obstruction
- most patients are asymptomatic
- older patients may present with chest pain or syncope
- neonates may show severe heart failure or shock
76
critical aortic stenosis?
patients with poor ventricular function, low cardiac output , and signs of shock and congestive heart failure.
77
signs of aortic valve stenosis?
- small volume, low rising pulse
- carotid thrill (always)
- ejection systolic murmur maximal at the upper right sternal edge radiating to the neck
- delayed and soft aortic second sound
- apical ejection click
78
describe exercise tolerance of those with aortic valve stenosis?
reduced exercise tolerance
chest pain on extertion
syncope
79
ECG of aortic valve stenosis?
it will inconsistently show evidence of left ventricular hypertrophy
80
CXR of aortic valave stenosis?
may reveal a prominent aorta because of post stenotic dilation and left ventricular hypertrophy
81
echocardiograph of aortic valve stenosis?
helps to accurately evaluate aortic valve morphology and estimate the pressure gradient across the LVOT
82
treatment of aortic valve stenosis?
infants with severe= balloon valvuloplasty (this is a procedure that stretches the aortic valve to improve symptoms of aortic stenosis)
older children and adults = surgical valvotomy or valve replacement
older children = balloon dilation
83
most common presentation of minor congenital heart disease?
murmur
(almost 30% of children have an innocent murmur though)
84
symptoms of heart failure?
- breathlessness
- sweating
- poor feeding
- recurrent chest infection
85
signs of heart failure?
- poor weight gain
- tachyponae
- tachycardia
- heart murmur
- enlarged heart
- hepatomegaly
- cool peripheries
86
describe extra cardiac anomalies?
- occur in 25% of infants (if they have significant cardiac disease)
- 1/3 o the infants will have established symptoms
- most ECA are in the musculoskeletal system or associated with a specific syndrome
- if this is presenti it will significantly increase the mortality in infants with CHD
87
- if there is left heart failure obstruction what may a severe lesion cause?
- what may closure of the duct under these conditions cause?
- atrial perfusion may be predominantly by the right to left blood flow via the atrial duct, so called duct dependant systemic circulation
- severe acidosis, collapse and death unless ductal latency is restored.
88
what is duct dependant coarction of the aorta caused by?
what is it commonly associated with?
due to tissue encircling the aorta at the duct's insertion point
- it will commonly be associate with a bicuspid aortic valve
89
in duct dependant coarction of the aorta, when the duct closes, what happens?
the aorta will also constrict
- causing severe obstruction to the left ventricular outflow
- this is the most common cause of collapse due to left outflow obstruction.
90
presentation of duct dependant coarction of the aorta?
- examination on the first day will be norm
- neonates preset with acute circulatory collapse at about 2 days of age when the duct closes
- a sick baby with severe heart failure
- absent femoral pulse
- severe metabolic acidosis
91
treatment of duct dependant coarction of the aorta?
surgical repaid or balloon dilation
92
describe the prenatal diagnosis of congenital heart defects in different countries?
- in high income countries between 18-20 weeks gestation can lead to 70% of those infants who require surgery in the first six months of life being diagnosed antenatally
