Congenital Flashcards
(126 cards)
1
Q
What is the most common form of ASD; accounting for two-thirds of cases?
A
Ostium Secundum ASDs
2
Q
Ostium Secundum ASDs involve what region of the IAS?
A
The region of the fossa ovalis (the most central part of the IAS).
3
Q
How can ASDs be acquired?
A
As a result of 1. Balloon mitral valvuloplasty, 2. EP procedures or 3. Due to puncture during right heart catheterisation or pacing procedures.
4
Q
What is often required to detect and fully assess an ASD?
A
‘Agitated’ saline contrast studies or a TOE.
5
Q
Which is the best window to view/assess an ASD in?
A
The subcostal window.
6
Q
True or false; right heart size may be dilated as a consequence of a left-to-right shunt in the presence of an ASD?
A
True.
7
Q
With an ASD, what may be present (indicating right heart volume overload)?
A
Paradoxical septal motion.
8
Q
In what part of the cardiac cycle does flow across an ASD usually occur?
A
Diastole.
9
Q
Atrial septal aneurysms are associated with ASDs; how are aneurysms defined?
A
As a bulge protruding at least 10mm into the right or left atrium (or, if mobile, swinging by at least 10mm from side to side) and with a diameter across their base of at least 15mm.
10
Q
How can an ASD be closed?
A
Percutaneously or surgically.
11
Q
When is percutaneous close of a secundum ASD appropriate?
A
If there is an adequate rim of tissue around the defect to allow deployment of a septal occluder device.
12
Q
Surgical closure of an ASD requires thoracotomy to open one of the atria and suture a patch over the defect, what is the patch made of?
A
Dacron or the patient’s own pericardium.
13
Q
What is the most common type of VSD?
A
Perimembranous VSD.
14
Q
Where are perimembranous VSDs located?
A
In the membraneous part of the septum (adjacent to the aortic and tricuspid valves).
15
Q
How can perimembranous VSDs be classified?
A
As either a perimembranous outlet defect, or a perimembranous inlet defect.
16
Q
Where are muscular VSDs located?
A
In the muscular part of the septum.
17
Q
How can muscular VSDs be classified?
A
As anterior, mid-muscular, posterior (or inlet) and apical.
18
Q
Multiple muscular VSDs are referred to as what?
A
A “Swiss cheese” septum.
19
Q
What kind of murmur to VSDs produce?
A
A pan-systolic murmur.
20
Q
True or false; the smaller the defect, the quieter the murmur.
A
False; the smaller the defect, the louder the murmur.
21
Q
Describe the flow relationship with the cardiac cycle in a VSD?
A
Doppler will usually show high velocity flow (from left-to-right) during systole, with lower-velocity flow during diastole.
22
Q
True or false; small VSDs are restrictive.
A
True.
23
Q
Why do restrictive VSDs result in high-velocity flow?
A
Because minimal equalisation of pressures occurs, leading to a high pressure gradient between the LV and RV, causing a high-velocity Doppler signal.
24
Q
True or false; RV dilatation occurs in the presence of a VSD.
A
False.
25
Why doesn't RV dilatation occur with a VSD?
Because blood moves in systole from the LV to the RV to the PA without pooling in the RV.
26
In the presence of a VSD, left heart dilation can occur, why?
Because increased pulmonary blood flow (and therefore increased pulmonary venous return to the LA) can cause LA and LV dilatation due to volume overload.
27
A left-to-right VSD shunt can cause pHTN which may result in what?
Reversal of the shunt (Eisenmenger syndrome) - whereby deoxygenated blood will enter the systemic circulation (bypassing the lungs).
28
Eisenmenger syndrome reduces the overall oxygen content in the arterial circulation, patients will clinically present how?
With cyanosis (a blue discolouration of the skin and tongue), together with breathlessness and a fall in exercise capacity.
29
True or false; many VSDs will spontaneously close.
True.
30
VSDs that close spontaneously may leave what?
A small ventricular septal aneurysm as a remnant.
31
AVSDs can be subdivided into what two categories?
Complete or partial.
32
How are complete AVSDs characterised?
By a primum ASD that is contagious with an inlet VSD and the presence of a common AV valve.
33
What is a common AV valve?
A single atrioventricular connection that has a left component (the mitral valve in a normal heart), and a right component (tricuspid valve in the normal heart) that typically has five leaflets.
34
What are the five leaflets of a common AV valve?
Anterior and posterior bridging leaflets, an anterior leaflet and right and left lateral leaflets.
35
How are partial AVSDs characterised from complete AVSDs?
By the absence of an inlet VSD.
36
What are the anatomical hallmarks of a partial AVSD?
A primum ASD and a cleft in the aMVL (there are distinct mitral and tricuspid valves with a complete and separate annulus).
37
What is Qp/Qs?
A ratio between the stroke volume of the right and left heart and is a measure of the severity of shunting.
38
What is the ductus arteriosus?
A normal foetal cardiac structure that connects the superior junction of the main PA and left PA to the descending Ao.
39
What is the purpose of the ductus arteriosus?
It allows the majority of blood to reach the systemic circulation directly (thus bypassing the lungs) which do not serve any ventilatory function.
40
Usually the ductus arteriosus closes within the first day of life, leaving behind a chord like remnant known as what?
The ligamentum arteriosum.
41
What are the main clinical features of a PDA?
Difficulty in breathing/failure to thrive (in neonates), tachycardia, a wide pulse pressure/bounding pulse, machinery or Gibson's murmur (a continuous systolic-diastolic murmur) and clubbing/cyanosis.
42
Will a PDA result in dilatation of the right or left heart?
Left heart.
43
Why does a PDA result in left heart dilatation?
Because left-to-right shunting will result in pulmonary over-circulation and left heart volume overload.
44
Why will no right heart dilatation occur with left-to-right shunting of a PDA?
Because shunting occurs at the level of the pulmonary artery.
45
True or false; with long-standing left-to-right PDA shunting, exposure of the pulmonary artery system to high pressure and increased flow results in a pulmonary HTN. If pulmonary vascular resistance exceeds systemic vascular resistance, ductal shunting will reverse (and become right-to-left).
True.
46
What may be present with a PDA that is also seen in aortic regurgitation?
Diastolic flow reversal in the descending Ao.
47
What medications can be used to close a PDA?
Prostaglandin inhibitors.
48
When might Prostaglandins be used to maintain patency of the ductus arteriosus?
In the presence of transposition of the great arteries.
49
Invasive techniques to close a PDA include what?
Percutaneous closure devices or surgical ligation.
50
What is the difference between a bicuspid and pseudo bicuspid AOV?
A bicuspid AOV has two functioning cusps (usually of equal size), with a single line of coaptation. Pseudobicuspid valves have three cusps, but with fusion of two of the cusps (by a raphe) so that the valve is functionally bicuspid.
51
True or false; a true bAOV (with only two leaflets) is a rare phenomenon.
True, in most cases, fusion or underdevelopment occurs.
52
What is the most common congenital abnormality?
bAOV.
53
True or false; bAOVs are recognised as an inherited congenital anomaly.
True.
54
A bAOV has a strong associated with aortic coarctation; in how many cases of coarctation is a bAOV present?
At least 50%.
55
Patients who require surgery for stenosis of a bicuspid valve do so on average how many years earlier than those with calcific degeneration of a tricuspid AOV?
5 Years.
56
Define the different types of bAOV?
Type 1 (right and left coronary fusion) | Type 2 (right and non coronary fusion) | Type 3 (left and non coronary fusion).
57
Name the different types of bAOV in order of most common to least common.
Type 1, Type 2 and Type 3.
58
What two echo findings are suggestive of a bAOV?
An eccentric closure line and the presence of systolic doming.
59
What is the only definitive treatment for a bAOV?
AVR.
60
What medications have a possible role in delaying the progression of aortic dilatation?
Beta-blockers and ARBs (angiotensin II receptor blockers).
61
How to ARBs work?
By reducing BP.
62
Surgery is indicated for aortic root diameters of what (with a bAOV)?
≥5.0cm
63
In the absence of a VSD, subvalvular AS most commonly results from what?
As a fixed obstruction in the LVOT (usually a fibromuscular ridge or membrane).
64
In the presence of a VSD, subvalvular AS most commonly results from what?
Posterior deviation of the conal septum.
65
When can dynamic obstruction in the LVOT occur?
In HOCM (predominantly in mid-late systole).
66
Why is AR associated with subvalvular AS?
Because of damage to the AOV secondary to the high-velocity jet.
67
Supravalvular AS is usually associated with what syndrome?
Williams syndrome.
68
In supravalvular AS there is a fixed obstruction in the ascending Ao due to diffuse narrowing or a discrete membrane. What are the three types of supravalvular AS?
The hourglass, diaphragmatic/membranous, and tubular type.
69
Aortic coarctation is a narrowing of the aorta that mostly occurs where?
Just distal to the origin of the left subclavian artery.
70
What are the names of the three arteries extending off the aortic arch (from left to right)?
Innominate, left carotid and left subclavian.
71
Aortic coarctations are slightly more prominent in males or females?
Males.
72
Explain the differences seen in BP in coarctation of the Ao.
There is a difference in BP measurements between the upper and lower body; lower, in the lower body due to restriction of flow from the coarctation.
73
What are the clinical signs of Aortic Coarctation (in regards to the pulse)?
Weak or absent femoral pulse and a radio-femoral delay (femoral pulse occurring later than the radial).
74
Pulsed-wave Doppler flow profiles of the abdominal Ao (from the subcostal position) will demonstrate what in the presence of aortic coarctation?
A delay in the systolic Doppler upstroke, and a continuation of antegrade flow into, or through diastole.
75
The holo-diastolic "runoff" seen on Pulsed-wave Doppler in the presence of aortic coarctation is indicative of what?
A haemodynamically significant coarctation.
76
A minority of patients with severe aortic coarctations develop what?
Collaterals as a means to physiologically bypass the aortic obstruction.
77
In the presence of severe aortic coarctation, why might Doppler gradients be falsely low?
Because of the formation of collaterals and the fact there is a reduced volume of integrate flow across the coarctation.
78
How can coarctation of the Ao be managed?
By surgical excision of the area of coarctation (followed by either end-end anastomosis of the Ao, or with use of a graft to bridge the resulting gap), OR by percutaneous angioplasty/stenting.
79
Is recoarctaion more common in those who undergo repair as a neonate, or later in life?
Those who undergo repair as a neonate.
80
What is the imaging hallmark for congenital pulmonary stenosis?
Systolic doming of the valve.
81
True or false; in the presence of PS, RVSP = PASP?
False.
82
How is PASP calculated when PS is present?
PASP = (4V*2 + RAP) - 4V*2 | where the first V is the max TR velocity and the second V is the PV velocity.
83
Failure to recognise PS may result in the misdiagnosis of what?
PHTN.
84
What peak velocity indicates mild, moderate and severe PS?
Mild; <3m/s | Moderate; 3-4m/s | Severe; >4m/s.
85
Ebstein’s anomaly is a malformation of the tricuspid valve and right ventricle characterised by what 5 features?
1. Adherence of the septal and posterior leaflets to the underlying myocardium.
2. Downward (apical) displacement of the functional annulus.
3. Dilation of the "atrialized" portion of the right ventricle, with various degrees of hypertrophy and thinning of the wall.
4. Redundancy, fenestrations and tethering of the anterior leaflet.
5. Dilatation of the true tricuspid annulus.
86
The RV is divided into what in Ebstein Anomaly?
An "atrialized portion" and the functional contractile RV.
87
True or false; the RV is typically dysfunction in Ebstein Anomaly?
True.
88
Ebstein anomaly is typically associated with what?
PFO/ASD and accessory conduction pathways (WPW syndrome).
89
A PFO/ASD associated with Ebstein anomaly can have bidirectional or right-to-left shunting, depending on what?
The compliance of the RV.
90
In Ebstein anomaly, patients may have abnormal left ventricular myocardium with what kind of appearance?
A non-compaction-like appearance.
91
Cases in which the tricuspid valve is not actually apically displaced, but the tricuspid valve leaflets are malformed, are termed what?
Tricuspid valve dysplasia.
92
Why is the degree of tricuspid regurgitation difficult to fully assess in Ebstein anomaly?
Because of the need for off-axis imaging to fully view the displaced coaptation plane. TR may be “wide open”/severe and thus appear to be a smooth and low-velocity flow.
93
In Ebstein anomaly, the difference between the tricuspid and mitral annulus exceeds what?
At least 8mm/m*2.
94
What are the four findings in Tetralogy of Fallot?
1. VSD
2. Overriding Aorta
3. RVOT Obstruction
4. RVH
95
True or false; the aortic root is frequently dilated in patients with TOF. Aortic regurgitant jets are frequently angled where?
Towards the VSD.
96
In TOF, apart from RVOT obstruction, what else be present (in this area)?
Pulmonary stenosis and a hypoplastic (small) pulmonary artery.
97
What is an "overriding Ao"?
Where to Ao is positioned more rightward than normal and sits over the VSD.
98
Why is there significant RVH in TOF?
Because the RV is more muscular than normal as a result of the right ventricular outflow tract obstruction and the need to pump harder.
99
Newborn with TOF present how?
With lower measured oxygen levels than normal or may have visibly blue lips or nail beds (called cyanosis).
100
True or false; as a result of most surgical repairs, the valve leaflets cannot close completely causing pulmonary regurgitation (which may cause RV dilatation/impairment).
True.
101
What are the types of TGA?
1. D-Loop TGA (complete) and,
| 2. Physiologically or congenitally corrected TGA (also known as L-Loop TGA).
102
Which type of TGA is the most common?
D-Loop TGA.
103
How do D-Loop and L-Loop TGA differ?
In D-Loop/complete TGA, the atria and ventricles are in the typical location however, the AO arises from the morphological RV whilst the PA arises from the morphological LV (there is ventriculoarterial discordance).
In L-loop/corrected TGA, the atria and arteries are in the typical location, however the ventricles are "switched". The right atrium enters the morphological LV which gives rise to the PA, and the left atrium enters the morphological RV which gives rise to the AO (AV and ventriculoarterial discordance exists/double discordance).
104
In D-loop TGA, the great arteries are transposed; what does this mean?
The aorta is associated with the RV and the pulmonary artery to the LV.
105
As this circulation (in D-loop TGA) is not physiologically sustainable, what must be present to support life?
There must be a communication between the systemic and pulmonary circulations either by a ASD, VSD or PDA (ASD may be created by a rashkind procedure).
106
What are the two surgical options for TGA?
Atrial or Arterial Switch.
107
Failure to recognize transposition can lead to an incorrect diagnosis of what?
pHTN.
108
Explain "atrial switch".
With an atrial switch, fundamentally, systemic venous blood is re-routed through the septum (baffled) directly to the LV to ultimately go to the pulmonary artery. The pulmonary venous blood is then baffled to the RV and on to the aorta.
109
Explain "arterial switch".
This represents a near anatomic correction of the trans- posed vessels. The aorta and pulmonary arteries are transected above the level of the valve and are switched.
110
With regards to great vessel location, which looks closer to normal between atrial and arterial switch for TGA?
Arterial.
111
True or false; in D-Loop/complete TGA the great arteries are parallel rather than crossing (as in a "normal" heart).
True.
112
What are the most common associated lesions with TGA?
VSD, pulmonary outflow tract obstruction and coarctation of the Ao.
113
What is a Rashkind procedure?
A balloon atrial septostomy, to create an ASD in order to improve blood oxygenation.
114
Almost all patients with TGA who reach adulthood have had prior reparative cardiac surgery, although some with what may survive?
A large VSD and pulmonary vascular disease sometimes survive with Eisenmenger physiology.
115
What type of arrhythmias are recognised complications of atrial baffle surgery in TGA?
Both atrial bradyarrhythmias and tachyarrhythmias.
116
When is Rastelli procedure used?
When d-TGA coexists with a large subaortic VSD and pulmonary stenosis.
117
Explain the Rastelli procedure.
A patch is placed to direct blood from the LV through the VSD to the aorta. The pulmonary valve is oversewn, and continuity is established between the RV and the pulmonary artery by means of a valved conduit.
118
What is an advantage of the Rastelli procedure?
The LV functions as the systemic ventricle.
119
What is inevitable with a Rastelli procedure?
Conduit degeneration and stenosis necessitation reoperation.
120
Atrial switch procedures are also termed what?
Senning or mustard procedures.
121
An atrial switch "Senning" procedure uses what to create the "baffle"?
The patients own tissue.
122
An atrial switch "Mustard" procedure uses what to create the "baffle"?
A synthetic material.
123
True or false; with surgically corrected TGA, the RV is always the systemic ventricle.
False; the RV is the systemic ventricle with "atrial switch" but the LV is the systemic ventricle with the "arterial switch".
124
True or false; the moderator band and tricuspid valve are always found in the morphological RV.
True.
125
True or false; the atrioventricular valves are always attached to the "correct" ventricle.
True.
126
Anomalous pulmonary venous drainage is associated with what type of ASDs?
Sinus Venous Defects.
