Congenital shunts and AV valve dysplasia Flashcards
(199 cards)
1
Q
When considering intracardiac shunts, cardiac enlargement involves only ………….
A
When considering intracardiac shunts, cardiac enlargement involves only those chambers that are included in the shunting blood’s route through the heart and lungs.
2
Q
There is a direct correlation between the clinical signs related to the cardiac shunt, the size of the defect, and the degree of volume overload in the involved chambers.
A
There is a direct correlation between the clinical signs related to the cardiac shunt, the size of the defect, and the degree of volume overload in the involved chambers.
3
Q
When one defect has been identified but there is enlargement of a chamber or vessel that is not normally part of the shunt pathway, another defect is probably present, or complications secondary to the shunt may exist.
A
When one defect has been identified but there is enlargement of a chamber or vessel that is not normally part of the shunt pathway, another defect is probably present, or complications secondary to the shunt may exist.
4
Q
Always measure pulmonary and aortic flow velocities in congenital heart disease. Increases in pulmonary flow suggest a ……. or ……. in the absence of PS. Increases in aortic flow suggest a ……… if AS is absent. These can help discover a defect not previously suspected.
A
Increases in pulmonary flow suggest a VSD or ASD in the absence of PS. Increases in aortic flow suggest a PDA if AS is absent. These can help discover a defect not previously suspected.
5
Q
Ventricular septal defect:
There are 4 types of VSD. Which ones?
A
Perimembranous
Supracristal
Muscular
Inlet
6
Q
Where are perimembranous VSDs located?
A
In the left ventricular outflow tract just proximal to the aortic valve, and blood flows into the right ventricular chamber under the tricuspid valve.
7
Q
What is the most common form of VSD?
A
High perimembranous type
8
Q
Supracristal VSDs are located?
A
In the right ventricular outflow tract just proximal to the pulmonary valve and the right coronary cusp of the aortic valve above the crista supraventricularis.
These defects have a high incidence of aortic insufficiency as the aortic valve leaflet prolapses into the defect.
9
Q
Inlet VSD are located?
A
Anywhere in the ventricular septum under the mitral and tricuspid valve leaflet.
10
Q
Inlet VSD is a type of?
A
Endocardial cushion defect
11
Q
Muscular defects can be located ….?
A
Anywhere along the muscular ventricular septum.
12
Q
VSDs are assessed both by …….?
A
VSDs are assessed both by size of the defect itself and by the amount of volume that is shunting.
13
Q
A large VSD approximates…?
A
The size of the aorta
14
Q
The size of the defect alone does not determine how much blood is shunted away from the systemic circulation toward the pulmonary circulation. The………….determines the degree of shunting.
A
The degree of pulmonary resistance determines the degree of shunting.
15
Q
Depending upon the type of VSD, aortic insufficiency may be a complicating factor as well. …….VSDs have a high incidence of concurrent aortic insufficiency.
A
Supracristal VSDs
16
Q
VSD: 2D and M-mode evaluation
Careful examination will allow most perimembranous defects to be seen on right parasternal long-axis LV outflow views where the ………… ventricular septum joins the …………. aortic wall.
A
Careful examination will allow most perimembranous defects to be seen on right parasternal long-axis LV outflow views where the muscular ventricular septum joins the anterior aortic wall.
Fig 9.1, 9.2
17
Q
4 chamber views should never be used to identify high membranous defects because?
A
Because these imaging planes often have normal echo dropout between the ventricular septum and atrioventricular junction
18
Q
Right ………………. views at the level of the aorta and left atrium or aorta and pulmonary artery also show high perimembranous defects.
A
Right parasternal transverse views at the level of the aorta and left atrium or aorta and pulmonary artery also show high perimembranous defects.
Fig 9.3, 9.4
19
Q
Right parasternal transverse views at the level of the aorta and left atrium or aorta and pulmonary artery also show high perimembranous defects.
The high membranous hole is typically seen….?
A
Under the tricuspid valve above the aorta
20
Q
Occasionally a VSD will be supracristal in the area proximal to both the …………… as opposed to under the…………………..
A
Occasionally a VSD will be supracristal in the area proximal to both the aortic and pulmonary valves as opposed to under the tricuspid valve.
21
Q
Will a supracristal defect be seen in the right parasternal long-axis view?
A
No
22
Q
Color-flow Doppler may show systolic turbulence within the right side of the heart, but a point of flow origin will not be seen on 4 ch or left ventricular outflow planes.
A
Color-flow Doppler may show systolic turbulence within the right side of the heart, but a point of flow origin will not be seen on 4 ch or left ventricular outflow planes.
23
Q
Supracristal VSDs are appreciated on right parasternal transverse images of the heart base just …………. to the pulmonary valve or on left cranial long-axis images of the aorta just …………….. to the aortic and pulmonary valves.
A
Supracristal VSDs are appreciated on right parasternal transverse images of the heart base just proximal to the pulmonary valve or on left cranial long-axis images of the aorta just proximal to the aortic and pulmonary valves.
Fig 9.5
Color-flow Doppler is usually necessary to accurately identify this defect.
24
Q
Ventricular septal defects may also be muscular. They may be found anywhere along the ventricular septum. Turbulent color flow within the …………. should prompt interrogation all along the septum.
A
Ventricular septal defects may also be muscular. They may be found anywhere along the ventricular septum. Turbulent color flow within the right ventricular chamber should prompt interrogation all along the septum.
Fig 9.6
25
Very small defects at any location may ot be seen with 2D echo, and Doppler studies are necessary to confirm the presence of the VSD.
Very small defects at any location may ot be seen with 2D echo, and Doppler studies are necessary to confirm the presence of the VSD.
Fig 9.7
26
One study showed that only ....% of ventricular septal defects were seen on 2D examinations without the aid of color-flow Doppler.
82%
27
The pathway of blood in ventricular septal defect includes the ..................................... Only those chambers and vessels will be volume overloaded.
The pathway of blood in ventricular septal defect includes the LV, RV, pulmonary artery, lung, LA, and back into the LV. Only those chambers and vessels will be volume overloaded.
28
VSD: The ............ and ......... are not involved in the shunt pathway and so should be normal if no other defects are complicating the picture.
The aorta and RA are not involved in the shunt pathway and so should be normal if no other defects are complicating the picture.
29
VSD: Even though the RV is involved in this shunt pathway, there are a couple of reasons that this chamber may actually be normal in size despite the presence of a ventricular septal defect. Which ones?
The right and left ventricles contract simultaneously and as the blood is shunted toward the right side of the heart during systole, its proximity to the main pulmonary artery allows blood to essentially enter the right ventricular outflow tract and bypass the right ventricular chamber itself.
Hemodynamically significant VSDs usually cause the right and left ventricular chambers to dilate.
30
VSD---shunt pathway:
LV---RV---PA....Lungs-----LA---LV
VSD---shunt pathway:
left ventricle----RV---PA....Lungs-----LA---LV
31
The RV may not be dilated in hearts with VSD even though it is in the shunt pathway.
The RV may not be dilated in hearts with VSD even though it is in the shunt pathway.
32
The ......of the VSD is a factor in how much dilation is present.
size
33
A very small defect may not create any measurable volume overload of the chambers, which helps when deciding how hemodynamically significant the shunt is.
A very small defect may not create any measurable volume overload of the chambers, which helps when deciding how hemodynamically significant the shunt is.
34
Chamber dilation is directly proportional to the .......................
Chamber dilation is directly proportional to the volume of blood being shunted.
35
Even without Doppler evaluation to calculate pressures and volume through the vessels, the size of the chambers and vessels are an indication of if the shunt volume is significant or not.
Even without Doppler evaluation to calculate pressures and volume through the vessels, the size of the chambers and vessels are an indication of if the shunt volume is significant or not.
36
Heart with significant shunts usually have.....
Significant volume overloads
37
The ............. may be dilated in animals with sizable ventricular septal defects, regardless of if there is dilation of the rest of the right side of the heart.
The pulmonary artery may be dilated in animals with sizable ventricular septal defects, regardless of if there is dilation of the rest of the right side of the heart. The artery sees all of the shunted blood.
38
What can help differentiate a dilated pulmonary artery due to VSD from the dilation seen in pulmonary stenosis.
VSD: The pulmonary artery will be enlarged all along its length from the level of the pulmonary valve cusps into the bifurcation of the pulmonary artery.
PS: There is poststonotic dilation and the diameter of the pulmonary artery will change distal the the valve. The pulmonary valve itself should move normally. Slow motion or frame-by-frame analysis will show the cusps moving completely toward the walls of the pulmonary artery during systole. Failure to do so is suggestive of pulmonary stenosis.
39
VSD: An M-mode feature that may help confirm the presence of a small defect when it cannot be seen on 2D exams and when Doppler is unavailable is?
Systolic tricuspid valve flutter. During systole shunted blood strikes the septal leaflet after passing through the defect.
This was present with VSD in one study. This finding is only reliable in the absence of tricuspid insufficiency when systolic flutter may be secondary to regurgitant flow as opposed to a shunt.
40
Aortic insufficiency is often seen in hearts with VSD especially if the VSD is of the ................type. The insufficiency is progressive and worsens with time in humans. Most insufficiencies are related to aortic ................
Aortic insufficiency is often seen in hearts with VSD especially if the VSD is of the supracristal type. The insufficiency is progressive and worsens with time in humans. Most insufficiencies are related to aortic valve prolapse.
41
VSD: The right ............ or .............. aortic cusp prolapses into the ventricular septal defect, and this is thought to be either secondary to a ............. effect, a lack of normal ............. support at the level of the aortic cusps, or both.
The right coronary or non coronary aortic cusp prolapses into the ventricular septal defect, and this is thought to be either secondary to a Venturi effect, a lack of normal muscular support at the level of the aortic cusps, or both.
42
VSD: A prolapsing aortic valve cusp can be diagnosed from right or left parasternal long-axis imaging planes. The aortic valve cups extends into the right ventricular chamber and breaks the line that would define a smooth transition between the anterior aortic wall and the ventricular septum. This prolapse usually results in .............., but the prolapse may exist for quite some time before AI develops.
A prolapsing aortic valve cusp can be diagnosed from right or left parasternal long-axis imaging planes. The aortic valve cups extends into the right ventricular chamber and breaks the line that would define a smooth transition between the anterior aortic wall and the ventricular septum. This prolapse usually results in insufficiency, but the prolapse may exist for quite some time before AI develops.
43
Most significant aortic regurgitation is associated with a large VSD, but having a small ................ VSD does not preclude concurrent considerable aortic insufficiency.
Most significant aortic regurgitation is associated with a large VSD, but having a small restrictive VSD does not preclude concurrent considerable aortic insufficiency.
44
Patients with VSD often have abnormal aortic valve motion such as ......................
Patients with VSD often have abnormal aortic valve motion such as1) asymmetric cusp movement or reduced excursion of a cusp. 2)They may also have a cusp override the ventricular septum where the center of the cusp is aligned with the center of the ventricular septum.
Both of these aortic valve abnormalities can be associated with aortic insufficiency but neuter is highly specific for the existence of aortic regurgitation. Both are indicators for the likely development of aortic regurgitation however because of subsequent prolapse of the cusp. Fig 9.2.
45
Aortic valve cusps size and ratio to each other has been evaluated in man. A ratio of right coronary cusp or non coronary cusp width to left coronary cusp width greater than 1.2 that increases over time is an indicator that aortic insufficiency will probably progress to hemodynamically significant levels.
The comparison is made to the .............. cusp since it is usually the least affected cusp in VSD while the ............... cusps are the ones that more often prolapse into the defect.
The comparison is made to the left coronary cusp since it is usually the least affected cusp in VSD while the right and non coronary cusps are the ones that more often prolapse into the defect.
Fig 9.9
46
VSD: Diastolic mitral valve flutter, an increased E point to septal separation, diastolic septal vibration and diastolic aortic valve flutter are all M-mode features that may be present with aortic insufficiency.
Diastolic mitral valve flutter, an increased E point to septal separation, diastolic septal vibration and diastolic aortic valve flutter are all M-mode features that may be present with aortic insufficiency.
Fig 4.110, 5.60, 5.61
47
VSD: The severity of AI should be evaluated with spectral and color flow Doppler if they are available. This added volume load to the heart affects the prognosis and even in significant aortic insufficiency may lead to CHF
The severity of AI should be evaluated with spectral and color flow Doppler if they are available. This added volume load to the heart affects the prognosis and even in significant aortic insufficiency may lead to CHF
48
VSD: ............ dilation of the membranous septum into the right ventricular chamber is sometimes seen. A thin portion of the ventricular septum just proximal to the aortic valve will be seen prolapsing toward the right side of the heart.
When it is perforate, the septal defect is usually seen i the ventral portion of the aneurysmal pocket and the shunted blood is directed posteriorly into the RV chamber. This membranous ventricular septum aneurysm does not have to be perforate however and can be associated with ......................... of a VSD:
Aneurysmal dilation of the membranous septum into the right ventricular chamber is sometimes seen. A thin portion of the ventricular septum just proximal to the aortic valve will be seen prolapsing toward the right side of the heart.
When it is perforate, the septal defect is usually seen i the ventral portion of the aneurysmal pocket and the shunted blood is directed posteriorly into the RV chamber. This membranous ventricular septum aneurysm does not have to be perforate however and can be associated with spontaneous closure of a VSD:Fig 9.10.
49
Spontaneos closure of a VSD is usually associated with the .......... form of defect.
Spontaneos closure of a VSD is usually associated with the perimembranous form of defect.
This has been reported in the dog by union of tissue from the septal leaflet of the tricuspid valve to the defect or from fibrous proliferation of tissue surrounding the defect.
50
Chordae tendinae attaching to the aneurysmal dilation or fibrous adhesion over the VSD can sometimes be seen if the redundant tissue is associated with the septal leaflet of the tricuspid valve. Aortic insufficiency may be seen i association with the dilation but is usually mild in severity.
Chordae tendinae attaching to the aneurysmal dilation or fibrous adhesion over the VSD can sometimes be seen if the redundant tissue is associated with the septal leaflet of the tricuspid valve. Aortic insufficiency may be seen i association with the dilation but is usually mild in severity.
51
Patients with VSD have ......... enlargement with a dilated LV diastolic dimension, normal wall thickness to chamber size ratios (suggesting adequate compensatory hypertrophy), and normal to increased systolic function.
eccentric
52
Spectral and Color Flow Doppler evaluation of VSD:
very small defects may require color Doppler examination to confirm their presence. It is the assessment of their hemodynamic significance where Doppler ultrasound is especially useful. While color flow Doppler can identify the defect and aid in assessing the size of a VSD, the hemodynamic significance of the defect is based on...?
Ventricular size
Shunt ratios
Chamber pressures
53
Color-flow Doppler finds most VSDs, but PW Doppler alone can also be utilized. ............ systolic flow is seen with spectral and with color flow Doppler if a VSD is present.
Color-flow Doppler finds most VSDs, but PW Doppler alone can also be utilized. Aliased systolic flow is seen with spectral and with color flow Doppler if a VSD is present. Fig 9.1-9.7
54
VSD: When a pulsed Doppler gate is placed along the VSD on a tipped LV outflow view, diastolic filling form the tricuspid valve may be recorded. Tricuspid inflow will be .......... and .......... just as VSD flow is. Tricuspid inflow however is typically not ......... and is present during ............
When a pulsed Doppler gate is placed along the VSD on a tipped LV outflow view, diastolic filling form the tricuspid valve may be recorded. Tricuspid inflow will be positive and upward just as VSD flow is. Tricuspid inflow however is typically not aliased and is present during diastole.
55
VSD: PW Doppler: The aliased color-flow signal should cross the ventricular septum and show an area of ............. on the LV side of the defect in most cases.
The aliased color-flow signal should cross the ventricular septum and show an area of flow convergence on the LV side of the defect in most cases.
56
A restrictive VSD is defines as one that does not .............?
A restrictive VSD is defines as one that does not elevate pulmonary vascular pressure.
57
Restrictive VSD: A pressure gradient will exist between the 2 ventricular chambers with a ratio of pulmonary to aortic pressure ratio of less than ............
A pressure gradient will exist between the 2 ventricular chambers with a ratio of pulmonary to aortic pressure ratio of less than 0.3
58
Nonrestricitve VSDs have a pulmonary to aortic pressure ratio of > .............
Nonrestricitve VSDs have a pulmonary to aortic pressure ratio of > 0.66
59
The velocity of blood flow through a small restrictive VSD should be high reflecting left ventricular pressure of greater than ...... mmHg and RV pressure of approximately .... mmHg. A pressure gradient > .......mmHg is expected, and a velocity close to ..... m/s should be recorded across the defect. Fig 9.11
The velocity of blood flow through a small restrictive VSD should be high reflecting left ventricular pressure of greater than 100 mmHg and RV pressure of approximately 20 mmHg. A pressure gradient > 80 mmHg is expected, and a velocity close to 5 m/s should be recorded across the defect. Fig 9.11
60
Documenting velocities and pressure gradients consistent with restrictive flow suggests that the effect of the shunt is hemodynamically ........... at the time of the exam.
Documenting velocities and pressure gradients consistent with restrictive flow suggests that the effect of the shunt is hemodynamically insignificant at the time of the exam.
61
Restrictive VSDs have ......pressure gradients
High
62
Pulmonary to aortic pressure ratios:
.....= hemodynamically significant.
0.66= hemodynamically significant.
63
Large VSDs allow the pressure between the right and left ventricles to ................., and ........... pressure gradients will exist. The velocity of blood flow across the shunt will therefore be ................
Large VSDs allow the pressure between the right and left ventricles to equilibrate, and smaller pressure gradients will exist. The velocity of blood flow across the shunt will therefore be lower. Fig 9.12
Velocity of blood flow will also be lower secondary to large aperute, which allows blood to flow through with less turbulence than if the defect was smaller.
64
VSD: Lower gradient are indicative of ..........?
Lower gradient are indicative of larger defects, higher right ventricular pressures and hemodynamically significant shunts.
65
Obtaining a systemic blood pressure and subtracting the pressure gradient across the VSD from it will provide a good estimate of right-sided pressure in the absence of ...........
Obtaining a systemic blood pressure and subtracting the pressure gradient across the VSD from it will provide a good estimate of right sided pressure in the absence of LV outflow obstruction.
66
VSD: In the absence of pulmonary stenosis, the right-sided pressure is equal to ...................pressures, and the presence and degree of pulmonary hypertension can be assessed.
In the absence of pulmonary stenosis, the right-sided pressure is equal to pulmonary artery systolic pressures, and the presence and degree of pulmonary hypertension can be assessed.
67
VSD: Pulmonary artery pressures of less than ..... mmHg would not be of concern; pressures between ... and about .... or so suggest the presence of moderate pulmonary hypertension, while pressures above .....or.....mmHg denote the existence of serious pulmonary hypertension.
Dogs with calculated pressure gradients of ..... mmHg or higher typically have a very good prognosis.
Pulmonary artery pressures of less than 30 mmHg would not be of concern; pressures between 50 and about 80 or so suggest the presence of moderate pulmonary hypertension, while pressures above 80 or 90 mmHg denote the existence of serious pulmonary hypertension.
Dogs with calculated pressure gradients of 80 mmHg or higher typically have a very good prognosis.
68
VSD: Low pressure gradients=
Large defects and/or pulmonary hypertension.
69
The normal flow profile representing flow across a VSD is .......... in shape. This reflects?
The normal flow profile representing flow across a VSD is plateau in shape. This reflects a pressure gradient from the right to left ventricle that does not change throughout the systolic time period.
70
VSD: The peak velocity and pressure gradient of a flow profile that peaks early and declines throughout systole should be measured at ............. Why?
End systole. Fig 9.13
This is more representative of the true pressure gradient between the 2 ventricles.
In these patients peak LV pressure is reached before peak RV pressure, and measuring end systolic velocity of the shunt is a more accurate reflection of peak RV pressure. Using early peak velocity in these cases will underestimate right ventricular pressure.
71
What else can cause an underestimation of right ventricular pressure (besides measuring in early in systole) in VSD patients?
RBBB: presumably because of asynchronous contraction and delayed elevation in RV pressure.
72
Use .........velocity in VSD flow profile for the most accurate assessment of peak RV pressure.
End systolic
73
Recording flow velocity across a tricuspid regurgitant jet when present is another way to measure RV pressure. The pressure gradient across the insufficient flow will reflect RV pressure and in the absence of ............... will also reflect pulmonary vascular pressure.
pulmonary stenosis
Similar estimates of RV pressure when using both the TR if present and the VSD pressure gradient is a way to confirm and validate the assessment of RV pressure.
74
All of the shunted blood volume must enter the pulmonary artery in VSD patients. The velocity of blood flow within the artery will increase in direct proportion to .......................... This reflects the physical law of ............. that states that when all other factors are held constant, flow in equals flow out and velocity must increase between the 2 areas in order to maintain this relationship.
All of the shunted blood volume must enter the pulmonary artery in VSD patients. The velocity of blood flow within the artery will increase in direct proportion to the amount of excess volume flowing throughout the defect. This reflects the physical law of continuity that states that when all other factors are held constant, flow in equals flow out and velocity must increase between the 2 areas in order to maintain this relationship.
Small shunt volumes will not elevate velocities to any great degree.
75
When the pulmonary artery dilates secondary to the volume overload, flow velocity may not increase.
When the pulmonary artery dilates secondary to the volume overload, flow velocity may not increase.
76
VSD: The development of PH will reduce the pressure gradient, which will decrease the velocity of the shunted blood as well as the amount of blood being shunted from left to right. Therefore, a VSD may be large but pulmonary flow velocity may not be high.
VSD: The development of PH will reduce the pressure gradient, which will decrease the velocity of the shunted blood as well as the amount of blood being shunted from left to right. Therefore, a VSD may be large but pulmonary flow velocity may not be high.
All causes of PH create similar changes.
77
In the absence of PS: the higher the pulmonary artery flow velocity, the more significant the ..........................
In the absence of PS: the higher the pulmonary artery flow velocity, the more significant the volume being shunted.
78
VSD: RV stroke volume can be calculated by obtaining .............. from the .............. or ............, both of which will reflect the volume flowing through the pulmonary system.
RV stroke volume can be calculated by obtaining flow velocity integrals from the pulmonary artery or mitral valve, both of which will reflect the volume flowing through the pulmonary system.
79
VSD:
RV stroke volume can be calculated by obtaining flow velocity integrals from the pulmonary artery or mitral valve, both of which will reflect the volume flowing through the pulmonary system.
The aortic flow velocity integral represents systemic volume. Multiplying these integrals by the .................... of the valve orifices allows volume to be determines and a shunt ratio (............) can be calculated.
The aortic flow velocity integral represents systemic volume. Multiplying these integrals by the cross-sectional area of the valve orifices allows volume to be determines and a shunt ratio (Qp:Qs) can be calculated.
Chapter 4
80
Qp:Qs calculation in VSD patients: Accurate planes through the measured areas, good Doppler tracing, and experience will increase the accuracy of calculating volumetric flow and shunt ratios. A ratio of greater than ....... is considered to have significant hemodynamic effects on the heart, and a ratio in excess of .........warrants surgical correction of the defect i people. A ratio of less than ........ is usually considered to be restrictive in nature, and not significant enough to warrant closure.
A ratio of greater than 2.0 is considered to have significant hemodynamic effects on the heart, and a ratio in excess of 2.5 warrants surgical correction of the defect i people. A ratio of less than 2.1 is usually considered to be restrictive in nature, and not significant enough to warrant closure.
81
VSD----Qp:Qs
| 2.5:1 =
2.5:1 = Hemodynamically signifianct= surgical candidate in man
82
Analysis of proximal flow convergence (PISA) has been shown to be an effective way of assessing ........... size and ...............fractions and volumes. This method has also been used to assess shunt ratios (............) defect size and shunt volume i man, ans shows significant correlation with cathterization methods in the presence of large VSDs (r = 0.90), (r= 0.93, (r= 0.90), respectively.
Analysis of proximal flow convergence (PISA) has been shown to be an effective way of assessing mitral regurgitant orifice size and regurgitant fractions and volumes. This method has also been used to assess shunt ratios (Qp-Qs) defect size and shunt volume i man, ans shows significant correlation with cathterization methods in the presence of large VSDs (r = 0.90), (r= 0.93, (r= 0.90), respectively.
83
The largest isovelocity ring is identified at end systole to coincide with the highest pressure gradient. The radius is measured from the defect to the first aliased line on the ........ side of the defect, and the Nyquist limit is noted. Peak velocity is recorded for the shunted blood, and the flow velocity integral is traced from flow profiles across the defect. Qp-Qs (1/min) is calculated from the following equation: ....
The largest isovelocity ring is identified at end systole to coincide with the highest pressure gradient. The radius is measured from the defect to the first aliased line on the LV side of the defect, and the Nyquist limit is noted. Peak velocity is recorded for the shunted blood, and the flow velocity integral is traced from flow profiles across the defect. Qp-Qs (1/min) is calculated from the following equation:
Qp-Qs (1/min) = (PISA x NL X FVI X HR)/ V max
Where PISA is the radius of the isovelocity hemisphere, NL = Nyquist limit, FVI = flow velocity integral of VSD flow, HR = heart rate, Vmax = peak VSD velocity.
Fig 9.1, 9.2 and 9.14
84
VSD: The shunt ratio calculated with PISA correlates well with shunt ratios calculated by spectral Doppler (r= 0.96) but tended to underestimate true shunt fractions derived by cauterization methods and spectral Doppler.
VSD: The shunt ratio calculated with PISA correlates well with shunt ratios calculated by spectral Doppler (r= 0.96) but tended to underestimate true shunt fractions derived by cauterization methods and spectral Doppler. This method proved to be more accurate with large defects and can differentiate between large and small shunts.
85
Patent ductus arteriosus:
| The reported incidence of this congenital defect in dogs varies from ........%.
The reported incidence of this congenital defect in dogs varies from 11-32%.
86
PDA has been seen in most breeds but ............... all have an increased risk for minting a patent ductus.
Poodles, Keeshonds, cocker spaniels, German shepherds, pomeranians, collies, shetland sheepdogs, CKCS, springer spaniels
The defect is also common in calves and cats, but is rare in the horse.
87
PDA; since its other clinical and radiographic features are usually very diagnostic and clear cut, echo is not necessary to make the diagnosis of PDA. Ehco will however confirm the diagnosis, especially if there are any conflicting clinical or physical signs, and it identifies the presence of other coexisting defects.
since its other clinical and radiographic features are usually very diagnostic and clear cut, echo is not necessary to make the diagnosis of PDA. Ehco will however confirm the diagnosis, especially if there are any conflicting clinical or physical signs, and it identifies the presence of other coexisting defects.
88
PDA: Currently echo plays a role in measurement of ......... and definition of .......... when planning for catheter-base occlusion of a ductus.
Currently echo plays a role in measurement of ductal diameter and definition of ampulla morphology when planning for catheter-base occlusion of a ductus.
89
PDA: includes the following in its shunt pathway:.........
Echo images show ......................of all of these structures.
The descending aorta ----main pulmonary artery-----, lungs, -----LA,----- LV, and back to the ascending aorta up to the level of the ductus.
Echo images show volume overload of all of these structures. Fig 9.15
90
PDA: The larger the shunt, the larger the volume overload. The................. are not part of the pathway and should not be enlarged if there are not other defects or complications.
The larger the shunt, the larger the volume overload. The RA and RV are not part of the pathway and should not be enlarged if there are not other defects or complications.
91
PDA: Long-axis images show bowing of the inter ventricular and atrial septum's toward the right side of the heart. LV outflow and transverse views typically show a large LA, and the LA to aortic root ratio will be large.
Long-axis images show bowing of the inter ventricular and atrial septum's toward the right side of the heart. LV outflow and transverse views typically show a large LA, and the LA to aortic root ratio will be large.
92
PDA: A large pulmonary artery is seen on both right and left parasternal transverse images of the heart base. The dilation includes:
The artery at the level of the pulmonary valve and the right and left main pulmonary artery branches.
Fig 9.16
93
Differentiation of the dilated pulmonary artery seen with PDA and the artery dilation seen with pulmonary hypertension or pulmonic stenosis is usually possible. How?
Pulmonic stenosis rarely causes dilation of the artery at the level of the valves and the poststenotic dilation is evident by vessel walls diverging away from each other beyond the stenotic lesion.
An artery dilated secondary to pulmonary hypertension will have a large diameter at the level of the pulmonary valve but may also show concurrent RV changes of hypertrophy and possible dilation if the pulmonary vascular pressures are high enough.
94
PDA. The ductus is oriented from the aorta to the pulmonary artery in a way that directs flow up toward the pulmonary valve. One or more of the pulmonary valve cusps often .............. as ductal flow strikes them. They may ........... significantly but can remain competent. Dilation of the pulmonary artery may also prevent cusps from coapting properly causing regurgitation.
The ductus is oriented from the aorta to the pulmonary artery in a way that directs flow up toward the pulmonary valve. One or more of the pulmonary valve cusps often prolapse as ductal flow strikes them. They may prolapse significantly but can remain competent. Dilation of the pulmonary artery may also prevent cusps from coapting properly causing regurgitation.
95
PDA: LV function:
Systolic function is depressed in dogs with PDA with typical FS of less than ..... %, systolic time intervals (PEP/ET) > ......., and 2D measurement of ejection fraction using Simpons' Rule of less than ......%.
Systolic function is depressed in dogs with PDA with typical FS of less than 25%, systolic time intervals (PEP/ET) > 0.44, and 2D measurement of ejection fraction using Simpons' Rule of less than 40%.
Fig 9.17
These parameters are all preload and afterload dependent and are not necessarily a good indicator of myocardial contractility.
96
PDA: Despite signifiacnt dilation of the LV chamber in most dogs, there is often inadequate hypertrophy of the wall and septum. This, and the fact that the shunt is beyond the ventricular chamber elevate the systolic wall stress. As a result, FS i hearts with a PDA are often ...............
As a result, FS i hearts with a PDA are often low or within the normal range.
97
PDA: A preload independent and heart rate corrected myocardial ...... .......... (.........) may be a better indicator of myocardial contractility than fractional shortening or ejection fraction.
A preload independent and heart rate corrected myocardial fiber shortening (VCFc) may be a better indicator of myocardial contractility than fractional shortening or ejection fraction.
98
VCFc is inversely and linearly correlated with myocardial wall stress. In other words, as wall stress increases the velocity of myocardial fiber shortening ........
VCFc is inversely and linearly correlated with myocardial wall stress. In other words, as wall stress increases the velocity of myocardial fiber shortening decreases.
99
In children with PDA, contractility has been shown to be normal despite abnormalities in FS and EF when these load independent and afterload corrected parameters are used for assessment.
In children with PDA, contractility has been shown to be normal despite abnormalities in FS and EF when these load independent and afterload corrected parameters are used for assessment.
100
FS is typically not elevated in hearts with PDA secondary to high afterload.
FS is typically not elevated in hearts with PDA secondary to high afterload.
101
Poorer systolic function is a common finding in hearts after PDA closure. The immediate decrease in LV function in dogs and people after PDA closure is the result of?
Result of decrease in LV diastolic dimension but an unchanged LV systolic dimension compared to pre-closure values.
102
LV function may take from 6 months to 1 hear to return to precolusre levels, and function may never return to normal after closure of the ductus in older animals and people.
LV function may take from 6 months to 1 hear to return to precolusre levels, and function may never return to normal after closure of the ductus in older animals and people.
103
Diastolic dysfunction has been documented in hearts with PDA both before occlusion and in long-term follow up evaluation.. Parameters of diastolic function that were evaluated include transmitral flow E:A (abnormal if 80 msec), mitral valve slow deceleration time (abnormal if >98 msec), and abnormal pulmonary venous flow (normal = PVs 0.25-0.53 m/s, PVd 0.42-0.70 m/s, PVar 0.12-0.28 m/s).
Diastolic dysfunction has been documented in hearts with PDA both before occlusion and in long-term follow up evaluation.. Parameters of diastolic function that were evaluated include transmitral flow E:A (abnormal if 80 msec), mitral valve slow deceleration time (abnormal if >98 msec), and abnormal pulmonary venous flow (normal = PVs 0.25-0.53 m/s, PVd 0.42-0.70 m/s, PVar 0.12-0.28 m/s).
104
PDA: Diastolic dysfunction abnormal when?
MV E:A .... msec
MV dec time > ..... msec
Pulmonary venous flow .........
- MV E:A 80 msec
- MV dec time > 98 msec
- Pulmonary venous flow abnormal.
105
Changes in the heart after surgical or device closure of a ductus include...?
- decreases in LV diastolic dimensions,
- decreases in LA size, and
- decreases in FS.
(The decrease in LA/Ao was seen on M-mode imaging but was not seen in 2D measurements of LA and aortic roots size until ca 1 month after ductal closure.)
106
PDA: There is a report of aneurysmal dilation of the aortic portion of the ductus arterioles after surgical ligation. This is a rare occurrence but is though to be the result of hematoma development in the wall of the ductus after using hemoclips, progressive dilation of the aortic portion of the ductus after closure at the pulmonary artery side, or from incomplete closure of the ductus with high velocity flow moving through a very narrow orifice creating increased stress on already potentially weak wall. This aneurysmal dilation can be seen on ........imaging planes. What will be seen?
right parasternal transverse imaging planes of the heart base at the level of the main pulmonary artery segment.
A large anechoic circular structure will be seen to the right side of the pulmonary artery and the proximal portion of the descending aorta.
107
PDA: CF Doppler shows turbulence within the main pulmonary artery when a patent ductus is present. The aliased signal will usually fill the artery and extend from ............up to the ........................
The aliased signal will usually fill the artery and extend from the bifurcation up to the pulmonary valve.
Fig 9.18
This can be seen on any of the view that shows the main pulmonary artery segment.
108
The turbulence in some animals completely fills the artery, and although the direction of flow from ............... into the ..................... segment can be discerned, no specific jet related to ductal flow can be identified.
The turbulence in some animals completely fills the artery, and although the direction of flow from descending aorta into the main pulmonary artery segment can be discerned, no specific jet related to ductal flow can be identified. When smaller shunts are present however, a well-defined jet is usually seen on right parasternal transverse images even if the ductus is not actually seen. Fig 9.19
109
PDA: Imaging of the ductus from right transverse views is less successful than from left cranial transverses views, which have up to a .....% visualization rate.
Imaging of the ductus from right transverse views is less successful than from left cranial transverses views, which have up to a 96% visualization rate.
110
PDA: The ductus is a hypoechoic structure between the main pulmonary artery near its bifurcation and the aorta. The pulmonary artery and its bifurcation should be clearly images and then subtle twisting and rocking of the transducer in the area of the ductus while color-flow Doppler is on will allow visualization of the ductus. The use of CF Doppler helps identify the ductus.
The ductus is a hypoechoic structure between the main pulmonary artery near its bifurcation and the aorta. The pulmonary artery and its bifurcation should be clearly images and then subtle twisting and rocking of the transducer in the area of the ductus while color-flow Doppler is on will allow visualization of the ductus. The use of CF Doppler helps identify the ductus. Fig 9.20, 9.21
111
PDA: The jet originates just .......... ............. of the pulmonary artery on the right side of the image and flows ..................
The jet originates just proximal to the bifurcation of the pulmonary artery on the right side of the image and flows upward toward the pulmonary valve.
112
PDA: Identification of a tapering ductus and measurements of ductal diameter can then be made for possible catheter-based occlusion procedures. How should the ductus be measured?
Without CF Doppler as color often bleeds onto the surroundings, and ductal measurements will be overestimated.
Freeze an image with the ductus identified by CF Doppler and then remove the color before measuring ductal diameter. The minimal ductal diameter as it enters the pulmonary artery and the size of the ampulla before it narrows should be measured. Fig 9.22 A large ampulla confirms the presence of a tapering ductus, which is necessary for catheter-based occlusions of PDAs.
113
PDA: ....... Nyquist limits also create increased aliasing in the area of the ductus and lead to overestimation of size.
Low Nyquist limits also create increased aliasing in the area of the ductus and lead to overestimation of size.
114
PDA: A ....................... helps improving resolution and measurement results.
A small sector angle helps improving resolution and measurement results.
115
PDA: Using CF Doppler, ductal diameter measurements are within 1 mm of true size in 48% of dogs and within 2 mm in 83% of dogs.
Using 2D imaging, ductal size is measured within 1 mm of true size in 72% of dogs and within 2 mm in 100% of dogs.
PDA: Using CF Doppler, ductal diameter measurements are within 1 mm of true size in 48% of dogs and within 2 mm in 83% of dogs.
Using 2D imaging, ductal size is measured within 1 mm of true size in 72% of dogs and within 2 mm in 100% of dogs.
Underestimation of ductal size is rare.
116
Length of the ......... and the ..........side of the ductus cannot be seen with transthoracic echo. Therefore, becoming more specific about the anatomy of a ductus such as elongated, tubular, or a ducuts with several constrictions is difficult without trans echopageal echo.
Length of the ampulla and the aortic side of the ductus cannot be seen with transthoracic echo. Therefore, becoming more specific about the anatomy of a ductus such as elongated, tubular, or a ducuts with several constrictions is difficult without trans echopageal echo (TEE)
117
measure ductal size at the pulmonary artery side from 2D images without CF Doppler.
measure ductal size at the pulmonary artery side from 2D images without CF Doppler.
118
Comparison of ductal measurements obtained from right and left parasternal images with and without CF Doppler as well as TEE with and without CF Doppler, showed that........................was the most accurate.
Comparison of ductal measurements obtained from right and left parasternal images with and without CF Doppler as well as TEE with and without CF Doppler, showed that TEE without CF Doppler was the most accurate.
119
Ampulla length and width can only be measured using ......and has high correlation with angiographic measurements of ductal size.
Ampulla length and width can only be measured using TEE and has high correlation with angiographic measurements of ductal size.
TEE can identify tubular ductal morphology, which typically requires surgical ligation. This is not always possible to identity with transthoracic imaging.
120
PDA: Spectral Doppler shows a very classic flow pattern that is not seen with any other congenital defect. Using any of the pulmonary artery views, place the Doppler beam over the artery with the gate located about................. Continuous ......... flow will be seen on the spectral tracing.
................. flow may be either continous from ductal flow that is swirling back toward the bifurcation or primarily systolic from right ventricular ejection flow.
Using any of the pulmonary artery views, place the Doppler beam over the artery with the gate located about halfway between the valves and the bifurcation. Continuous positive flow will be seen on the spectral tracing.
Fig 9.23
Negative flow may be either continous from ductal flow that is swirling back toward the bifurcation or primarily systolic from right ventricular ejection flow.
121
In cases where a distinct jet of ductal flow is present, the gate needs to be moved side to side within the artery toward the left main pulmonary artery segment before the continuous flow pattern is seen. The continuous upward flow is seen regardless of which imaging plane is used and regardless of if the Doppler cursor is pointed exactly parallel with flow.
In cases where a distinct jet of ductal flow is present, the gate needs to be moved side to side within the artery toward the left main pulmonary artery segment before the continuous flow pattern is seen. The continuous upward flow is seen regardless of which imaging plane is used and regardless of if the Doppler cursor is pointed exactly parallel with flow.
122
PDA: In order to obtain accurate flow velocities and pressure gradients across the ductus, the Doppler beam must line up along the shunting jet. This is usually obtained from ...?
Cranial left transverse imaging planes. Fig 9.24
123
PDA: The ductal flow is highest during...? Why?
Systole
Since the largest gradient in pressure between the aorta (over 100 mmHg) and the pulmonary artery (approximately 20 mmHg) occurs during systole.
During diastole, aortic pressure drops to around 60-80 mmHg or lower while diastolic pressure in the pulmonary artery drops to about 10 mmHg creating a lower pressure differential and lower flow velocity during diastole on the spectral Doppler flow profile of a PDA. The result is a spectral Doppler flow profile that is continuous but that increases and decreases in velocity with systole and diastole.
124
PDA: Since systolic pulmonary artery pressures should be approximately 20 and systolic aortic pressure should be above 100 mmHg, a gradient close to 100 mmHg is expected. A lower pressure gradient is seen if the ducts is ........... or if ............ is present.
A lower pressure gradient is seen if the ducts is very large or if pulmonary hypertension is present.
125
Pressure gradients in congenital heart disease provide information that is useful in the assessment of hemodynamic significance and prognosis. Since most PDAs are corrected, obtaining a pressure gradient in PDA is not as important as it is with other defects.
Pressure gradients in congenital heart disease provide information that is useful in the assessment of hemodynamic significance and prognosis. Since most PDAs are corrected, obtaining a pressure gradient in PDA is not as important as it is with other defects.
126
PDA: Stroke volume is high in a significantly shunting ductus because ..............
Stroke volume is high in a significantly shunting ductus because there is increased venous return to the left side of the heart.
127
PDA: Stroke volumes can double and even triple in the presence of a large ductus. This is manifested on echo Doppler examination by?
By an elevated aortic flow velocity. Fig 9.25.
| High aortic flow velocity therefore suggests the presence of significant ductal shunting.
128
Aortic flow velocities are usually elevated with PDA. The higher the velocity the more significant the shunt in the absence of aortic stenosis.
Aortic flow velocities are usually elevated with PDA. The higher the velocity the more significant the shunt in the absence of aortic stenosis.
129
PDA: Pulmonary to systemic flow ratios can be calculated. (see more in chapter 4) This involves recording both .................. flow profiles, measuring the flow .............of each of these flows to derive the area under the curve and multiplying these areas by the .....................
This involves recording both aortic and pulmonary flow profiles, measuring the flow velocity integral of each of these flows to derive the area under the curve and multiplying these areas by the diameter of the respective vessel.
130
To calculate the pulmonary to systemic shunt ratio in the case of PDA; it is important to remember that systemic flow is calculated from ............ velocity, while pulmonary flow is calculated from .............. Explain why?
it is important to remember that systemic flow is calculated from pulmonary artery velocity, while pulmonary flow is calculated from the aorta
since the shunted volume enters the pulmonary circulation after passing through the ascending aorta.
131
PDA----Qp:Qs
Qp: measured from .......... flow
Qs: measured from ........... flow.
Qp: measured from aortic flow
Qs: measured from pulmonary artery flow.
132
Mitral insufficiency is a common finding in most hearts with a PDA. This diminishes significantly as ventricular and atrial dimensions decrease after ductal closure.
This diminishes significantly as ventricular and atrial dimensions decrease after ductal closure.
Fig 9.26
133
A long-term study (9-121 months) showed a high percentage of dogs with mitral insufficiency after ductal closure via catheter-based devices or surgical ligation. Several of these dogs showed signs of degenerative valve disease, and the regurgitation may not have the same underlying cause as when the ductus was present. These degenerative changes were present in older dogs that are not normally predisposed to degenerative changes and also occurred at younger ages tha expected.
A long-term study (9-121 months) showed a high percentage of dogs with mitral insufficiency after ductal closure via catheter-based devices or surgical ligation. Several of these dogs showed signs of degenerative valve disease, and the regurgitation may not have the same underlying cause as when the ductus was present. These degenerative changes were present in older dogs that are not normally predisposed to degenerative changes and also occurred at younger ages tha expected.
Perhaps the turbulence associated with high volume and velocity flow across the mitral valve leaflets contributed to the development of degenerative changes on these valve leaflets.
Mitral regurgitation may be secondary to myocardial dysfunction before and sometimes after ductal closure, mitral annular dilation, or papillary muscle displacement as the heart dilates.
134
PDA: Aortic insufficiency can be present as well, and the incidence of this insufficiency remained unchanged after ductal closure via any method. Damage to the cusps and dilation of the aorta are hypothesized to be the cause of this commonly seen insufficiency in hearts with PDA:
Aortic insufficiency can be present as well, and the incidence of this insufficiency remained unchanged after ductal closure via any method. Damage to the cusps and dilation of the aorta are hypothesized to be the cause of this commonly seen insufficiency in hearts with PDA:
135
Aorticopulmonary window: This defect consists of?
A connection between the ascending aorta and the main pulmonary artery trunk or the right branch of the pulmonary artery.
There is virtually a window between the two vessels as opposed to a vessel or duct as in PDA. In severe cases, there is complete communication between the aorta and main pulmonary artery with no development of a septum between the 2 vessels. This window is usually large in size and in volume of shunting blood.
136
Aorticopulmonary window: Assciated defects include..?
```
VSD
Subaortic stenosis
Aortic arch interruption
MR
Double outlet right ventricle
Aoritc valve atresia
Bicuspid aortic valve
PDA
Tetralogy of Fallot
```
137
Transverse images of the aortic and pulmonary artery from the right and left sides of the thorax show the communication. Normal dropout of echoes in these imaging planes is typical. Features of a true ? aorticopulmonary window?
A true window has thick hyperechoic borders. Color-flow and spectal Doppler shows bi-directional shunting and flow directed toward the pulmonary valve in the main pulmonary artery segment.
138
Right to left shunting PDA: occurs when and why?
When pulmonary vascular pressure exceeds systemic pressure. This may occur because of over perfusion of the pulmonary lung field resulting in vasoconstriction and structural changes that include intimal proliferation and medial hypertrophy or because of retention of the high pulmonary artery resistance and pressure found in the fetus.
139
PDA: Shunting can be bi-directional or balanced when systemic and pulmonary vascular pressures are similar. The degree of pulmonary over circulation is determined by?
By the size of the ductus, and some large diameter PDAs have been shown to result in the development of pulmonary hypertension in dogs.
140
The diastolic component of sunning disappears first when............develops in hearts with PDA.
pulmonary hypertension
141
The cardiac changes associated with a reverse PDA are all related to PH. Diastolic aortic and pulmonary pressures will equilibrate first, and the ................. component of the shunting blood will be lost first.
diastolic
142
Reverse PDA: There will be concentric hypertrophy and possibly dilation of the RV chamber and main pulmonary artery dilation.
There will be concentric hypertrophy and possibly dilation of the RV chamber and main pulmonary artery dilation.
Fig 9.27
143
Reverse PDA: The right atrium may remain normal but when TR is present, --------- pressure rises significantly and the RA can be dilated. Paradoxical septal motion may be present as ................pressure increases. The left side of the heart will be .............secondary to a decrease in preload.
The right atrium may remain normal but when TR is present, RV pressure rises significantly and the RA can be dilated. Paradoxical septal motion may be present as RV pressure increases. The left side of the heart will be small secondary to a decrease in preload.
144
Reverse PDA: CF Doppler will no longer help define the ductal flow. There is a minimal pressure gradient across the defect that creates ................ Additionally, the packed cell volume is ............, which will also .......... flow velocity.
CF Doppler will no longer help define the ductal flow. There is a minimal pressure gradient across the defect that creates no turbulence. Additionally, the packed cell volume is high, which will also diminish flow velocity.
145
Reverse PDA: Flow velocities of tricuspid and pulmonary insufficiency, if present, are high and reflective of ...............and............ artery pressure.
Flow velocities of tricuspid and pulmonary insufficiency, if present, are high and reflective of high right ventricular and pulmonary artery pressure.
146
Reverse PDA: The pulmonary flow profile will exhibit rapid ................ and may show systolic .............
The pulmonary flow profile will exhibit rapid acceleration and may show systolic notching.
147
Reverse PDA: Is there a way to differentiate the cardiac changes associated with hypertension secondary to a reverse shunt from those resulting from other causes such as primary pulmonary hypertension or thromboembolic disease?
No. But a bubble study can be used to determine if the pulmonary hypertension is secondary to a PDA.
148
Atrial septal defects:
| ....................(3) seem predisposed to the development of ASD.
Old english sheepdogs, samoyeds, and boxers seem predisposed to the development of ASD.
ASD is reported as the most common congenital heart defect in Boxers.
149
3 different types of ASD occur. Which ones? Where are they located? and which is the most common one?
1. The most common defect: ostium secundum defect is located in the middle of the atrial septum. It is in the same area as the fossa ovalis. This defect is created when there is over absorption of the septum primum or there is flawed development of the septum secundum.
2. Less common is the ostium primer defect, which is located at the junction of the atrioventricular valves and the atrial septum. This ASD is a form of endocardial cushion defect and is created when the endocardial cushions do not close the ostium primum.
Because the endocardial cushions are involved, there are often associated defects of the atrioventricular valves.
3. The least common ASD id the sinus venous type located near the junction of the pulmonary vein and LA. This defect occurs when there is abnormal attachment of the right pulmonary vein into the cranial or caudal vena cava.
150
Patent foramen oval may exist in the same area as the ostium secundum but has less hemodynamic significant than a true atrial septal defect unless ......................
Patent foramen oval may exist in the same area as the ostium secundum but has less hemodynamic significant than a true atrial septal defect unless right atrial pressures become elevated and a right to left shunt develops.
151
ASD: The ...................(4) are all involved in the shunt pathway and will be volume overloaded.
The ........remains unaffected by this shunt.
The RA, RV, pulmonary artery and LA are all involved in the shunt pathway and will be volume overloaded.
The LV remains unaffected by this shunt.
152
ASD: The degree of volume overload is dependent upon the size of the defect and the pressure difference between the left and right atrium.
The degree of volume overload is dependent upon the size of the defect and the pressure difference between the left and right atrium.
153
ASD: Large defects will volume overload the chambers and artery significantly and may lead to secondary .....................
Large defects will volume overload the chambers and artery significantly and may lead to secondary tricuspid and mitral insufficiencies.
154
ASD: Small defects may not show any measurable or visually obvious dilation on 2 D images.
Small defects may not show any measurable or visually obvious dilation on 2 D images.
155
ASD: Shuntpathway?
LA-----RA-------RV-------PA-----Lungs------LA
156
ASD: Large volume overloads of the right side of the heart will elevate RV diastolic pressure, and .................. is seen once right-sided pressures exceed LV diastolic pressure. The motion is subtle when the difference is minimal but can become dramatic with large with larger disparities in pressure.
paradoxical septal motion
Paradoxical septal motion is the most common echo hemodynamic change seen in man with large atrial septal defects. Fig 9.28.
157
Ostium primum defects typically have abnormal ............. since the annuluses of these valves are located at the junction of what would normally be the atrial and ventricular septums. Fig 9.29, 9.30
Ostium primum defects typically have abnormal atrioventricular valves since the annuluses of these valves are located at the junction of what would normally be the atrial and ventricular septums.
158
Ostium primum: Tricuspid dysplasia and ......... may be seen with this type of atrial septal defect. ........... mitral valve leaflets are often seen as well, and the presence of a ......... mitral valve almost always implies the presence of an ostium primum atrial septal defect.
Tricuspid dysplasia and atresia may be seen with this type of atrial septal defect. Cleft mitral valve leaflets are often seen as well, and the presence of a cleft mitral valve almost always implies the presence of an ostium primum atrial septal defect.
159
Patent foramen ovale is seen in the middle of the atrial septum just as secundum defects are. The ............ that would normally close the foramen on the left side of the atrial septum may be seen on RT images. Without seeing the ............ of the fossa ovals, however, it is difficult to differentiate the shunt of an ostium secundum from a patent foramen ovale.
Patent foramen ovale is seen in the middle of the atrial septum just as secundum defects are. The membrane that would normally close the foramen on the left side of the atrial septum may be seen on RT images. Without seeing the membrane of the fossa ovals, however, it is difficult to differentiate the shunt of an ostium secundum from a patent foramen ovale. Fig 9.31-9.32
160
There is often an area in the middle of the atrial septum on 4 ch views that appears to have a defect. This is usually just the thin membrane that closed the fossa ovals, and it does not reflect sound very strongly; resulting in the appearance of an orifice.
Rely on ............ to help define this as a real communication between the atria.
There is often an area in the middle of the atrial septum on 4 ch views that appears to have a defect. This is usually just the thin membrane that closed the fossa ovals, and it does not reflect sound very strongly; resulting in the appearance of an orifice.
Rely on color-flow Doppler to help define this as a real communication between the atria.
161
Drop out of the middle portion of the atrial septum is often seen in normal hearts.
Drop out of the middle portion of the atrial septum is often seen in normal hearts.
162
Spectral and CF Doppler helps identify the presence of an ASD when it is too small to see or when there is count as the whether a perceived defect in the atrial septum is real.
Spectral and CF Doppler helps identify the presence of an ASD when it is too small to see or when there is count as the whether a perceived defect in the atrial septum is real.
163
ASD: Color Doppler may show flow acceleration on the ...... side of the atrial septum, turbulence through the defect itself, and .......colored slower flow as the shunted blood enters the RA.
Color Doppler may show flow acceleration on the left side of the atrial septum, turbulence through the defect itself, and red colored slower flow as the shunted blood enters the RA. Fig 9.30, 9.31
164
ASD: Gradients are small however and depending on the transducer and the depth of interrogation, the velocity of shunting blood may not exceed the Nyquist limit. ............. the Nyquist limit on the color bar helps identify this low velocity flow. The more ............... the ASD is the more likely an aliased signal will be seen.
Decreasing the Nyquist limit on the color bar helps identify this low velocity flow. The more restrictive the ASD is the more likely an aliased signal will be seen.
165
An ASD has almost continuous positive flow. Flow is more prominent during atrial..... coinciding with the onset of the .......... complex.
Atrial diastole (ventricular systole) coinciding with the onset of the QRS complex.
166
ASD: The first prominent peak may be ................... This positive waveform should return almost to ............., and a second lower velocity peak should be seen during atrial ..............
The first prominent peak may be biphasic. This positive waveform should return almost to baseline, and a second lower velocity peak should be seen during atrial systole. Fig 9.33
167
ASD: ......................flow is often recorded on right parasternal 4 ch views, and this flow needs to be differentiated from atrial septal defect flow. Both flows are positive and have 2 phases to flow. How to differentiate?
Vena caval flow is often recorded on right parasternal 4 ch views, and this flow needs to be differentiated from atrial septal defect flow. Both flows are positive and have 2 phases to flow. Vena caval flow however varies with respiration and has a sharper more defined positive flow profile with rapid acceleration and deceleration when compared to ASD flow. Vena caval flow also has a much smaller peak coinciding with the P wave.
168
ASD: The mean pressure gradient, not the peak, should be obtained by tracing the shunt flow profile, which helps differentiate between hemodynamically significant defects and small restrictive ones. How?
Restrictive ASDs will have higher velocities because the pressures between both atria do not equilibrate as they would with large communications. A restrictive ASD will have velocities that reflect 5 to 10 mm of difference in pressure between the 2 chambers.
169
Recording tricuspid and mitral flow also helps identify the presence of an ASD. This is only valid if not MR or TR are present. How should this be assessed?
A larger volume of blood will flow past the tricuspid valve than the mitral valve in the presence of an ASD, and flow velocity will therefore be greater across the tricuspid valve than the mitral valve when an ASD is present. These flows can be recorded from left parasternal apical and cranial transverse views of the heart.
170
Trans .............. flow velocity will be higher than ......... flow velocity when an ASD is present. Pulmonary artery flow velocity will also be elevated.
Trans tricuspid flow velocity will be higher than transmitral flow velocity when an ASD is present. Pulmonary artery flow velocity will also be elevated.
171
ASD: The shunted volume of blood must past the pulmonary artery, and velocity of pulmonary flow is increased with large volume shunts. Although small defects may not increase flow velocities much, a shunt must be suspected when velocities are ...................
The shunted volume of blood must past the pulmonary artery, and velocity of pulmonary flow is increased with large volume shunts. Although small defects may not increase flow velocities much, a shunt must be suspected when velocities are above the normal range.
Pulmonary stenosis should be ruled out when pulmonary flow velocity is elevated.
172
ASD: Comparison of flow velocity integral of the pulmonary artery and the aorta provides an estimate of the severity of the shunt. The higher the pulmonary flow integral is when compared to aortic flow integral, the greater the volume of blood that must be flowing through this vessel as compared to the aorta. (see chapter 4) A ratio of ......or higher implies a hemodynamically significant shunt. Ratios > .....are usually considered to be significant enough to warrant surgical intervention.
A ratio of 2:1 or higher implies a hemodynamically significant shunt. Ratios > 2.5 are usually considered to be significant enough to warrant surgical intervention.
173
ASD: Large volume shunts may create pulmonary interstitial changes resulting in pulmonary hypertension. When this happens and RA pressure begins to exceed LA pressures, the shunt will .............
Large volume shunts may create pulmonary interstitial changes resulting in pulmonary hypertension. When this happens and RA pressure begins to exceed LA pressures, the shunt will reverse.
174
Reverse flow though a patent foramen is often seen with congenital heart disease that elevates right sided pressure such as .............. and ..................
such as pulmonary stenosis and tricuspid dysplasia.
175
Reverse flowing atrial septal defects follow a different flow pathway and the .......... is now involved.
Reverse flowing atrial septal defects follow a different flow pathway and the LV is now involved.
176
Reverse flow ASD: Changes associated with pulmonary hypertension are seen including...?
Severe right ventricular hypertrophy and a very prominent pulmonary artery.
177
Reverse flow ASD. Doppler flow will be ............. when the shunt is interrogated on right parasternal 4 ch views. Aortic flow velocities will be elevated since the shunt now involves the vessel.
Doppler flow will be negative when the shunt is interrogated on right parasternal 4 ch views. Aortic flow velocities will be elevated since the shunt now involves the vessel.
178
Endocardial cushion defects:
| When both a very large ................ and a large .......................are present.
When both a very large ostium primum atrial septal defect and a large ventricular septal defect are present.
It may also be called complete atrioventricular canal or atrioventricular septal defect.
179
Endocardial cushion defects fall into 2 categories: which ones?
Incomplete (or partial) and complete
180
Endocardial cushion defects: Complete defects include?
an ostium primum atrial septal defect and a ventricular septal defect where a large portion of the inferior atrial septum and a large portion of the superior portion of the ventricular septum are missing. These 2 septal defects connect and the entire central portion of the heart is missing
181
Complete endocardial cushion defects: There is typically one large atrioventricular valve since the septal portion of the endocardial suction did not develop sufficiently to form the septal portions of the AV annuluses.
There is typically one large atrioventricular valve since the septal portion of the endocardial suction did not develop sufficiently to form the septal portions of the AV annuluses
182
Incomplete endocardial cushion defect resulting in an almost common atrium and abnormalities of the ..............
The mitral valve is often....
Incomplete endocardial cushion defect resulting in almost common atrium and abnormalities of the atrioventricular valves. The mitral valve is often cleft.
183
Endocardial cushion defects: 2D echo images are very dramatic. Common features?
The right parasternal 4 ch view shows a large atrial septal defect as well as the ventricular septal defect. Fig 9.34. The mitral and tricuspid valves originate from the endocardial fusion and are usually dysplastic. There often appears to be just one large atrioventricular valve with only the parietal leaflets of the tricuspid and mitral valves present. When septal mitral and tricuspid leaflets are present, they are usually continuous through the endocardial cushion defect. The RA, RV, and LA are always dilated.
The LV may be dilated. The valves are usually insufficient, and the defects are so large that both CF and spectral Doppler are of no help in determining the direction of flow.
184
Bubble studies:
| Help confirm the existence of R-L shunting. How is it performed?
Normal saline is drawn into a syringe, shaken vigorously, all large bubbles of air are pushed from the syringe leaving only micro bubbles within the solution. Several ml of saline are used in larger dogs, but about 1 ml is uses in cats and small animals.
The saline is injected into a peripheral vein while the heart is being imaged.
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Bubble studies: Which echo views should be used in ASD and VSD patients?
A right parasternal 4 ch view is used for the detection of atrial septal defects, and a right parasternal long-axis LV outflow view should be used for VSD.
Dense echoes associated with the air-filled fluid can be seen crossing the atrial or ventricular septum's into the left-sided chambers.
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Bubble studies: Why will a bubble study using cardiac images not help define the existence of a reverse PDA
Because the shunt in patent ductus arteriosus is extra cardiac and blood flows from the pulmonary artery into the descending aorta, a bubble study using cardiac images will not help define the existence of a reverse PDA. The abdominal aorta should be used instead. Fig 9.35
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Bubble studies: The dense echoes associated with the micro bubbles will show up in the abdominal aorta if a reverse PDA exists. It is important to rule out......since these reverse flows will aslo be seen in the abdominal aorta.
VSD and ASD
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Atrioventricular valve dysplasia:
Congenital dysplasia of the atrioventricular valves usually causes valvular insufficiency. The degree of dysplasia and regurgitation is very variable.
Congenital dysplasia of the atrioventricular valves usually causes valvular insufficiency. The degree of dysplasia and regurgitation is very variable.
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the cardiac changes associated with these defects are similar to those seen when the valvular insufficiencies are secondary to acquired valvular lesions. Cardiac changes associated with mitral dysplasia include?
Eccentric LV hypertrophy
Elevated parameters of LV function
LA dilation
Excessive wall and septal motion
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Right-sided changes associated with tricuspid dysplasia include?
RV volume overload
Possible paradoxical septal motion
RA dilation
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Atrioventricular valve dysplasia: The appearance of the valvular apparatur is extremely variable, and any combination of abnormally shaped leaflets, abnormal chordal attachments, and abnormal papillary muscles may be seen. Describe how the leaflets may look like.
The leaflets may be thick, long, short, contain clefts, or have some degree of commissural fusion. The papillary muscles may be abnormally shaped or elongated or large.
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Tricuspid dysplasia: Particularly common in?
Labrador retrievers, but other large breed dogs are also predisposed the the defect.
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Tricuspid dysplasia: The septal leaflet is typically tethered to the .......... side of the septum. Short chordae may be visible as the leaflet tries to move toward its normal closed position during systole. The middle of the leaflet often buckles away from the septum while the tips remain closely apposed to the septum.
The anterior leaflet is typically elongated and may come close to achieving closure of the tricuspid valves during systole.
The septal leaflet is typically tethered to the right side of the septum. Short chore may be visible as the leaflet tries to move toward its normal closed position during systole. The middle of the leaflet often buckles ........ from the septum while the tips remain closely apposed to the septum.
The anterior leaflet is typically ................. and may come close to achieving closure of the tricuspid valves during systole.
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It is sometimes difficult to define where the anterior leaflet of the tricuspid valve ends and where the chordae tendinae start.
It is sometimes difficult to define where the anterior leaflet of the tricuspid valve ends and where the chordae tendinae start.
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What is Ebstein's Anomaly?
An unusual variation of tricuspid dysplasia.
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Features of Ebstein's Anomaly?
The tricuspid annulus is actually displaced toward the apex of the right ventricle. The right atrial chamber is very large in this defect, and the ventricle is called atrialized. The annulus can be identified on right parasternal long-axis 4 ch views of the heart. The mitral and tricuspid annulus should be aligned almost directly across from each other in normal hearts. The tricuspid valve is typically a mm or 2 closer to the apex of the normal heart than the mitral annulus. With Ebstein's Anomaly, the tricuspid annulus is clearly displaced toward the apex. Fig 9.37
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Ebstein's Anomaly: Be sure to examine the ................carefully since a severely tethered leaflet may only move away from the septum at a more apical location and yield the appearance of a ............. Regardless, the valve is dysplastic.
Be sure to examine the septal cusp carefully since a severely tethered leaflet may only move away from the septum at a more apical location and yield the appearance of a displaced annulus. Regardless, the valve is dysplastic.
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TD: Even though the RA is enlarged because the leaflets close in a more apical location than normal, tricuspid insufficiency is not always severe. Often valves with very abnormal architecture on echo images are only mild to moderately incompetent.
Even though the RA is enlarged because the leaflets close in a more apical location than normal, tricuspid insufficiency is not always severe. Often valves with very abnormal architecture on echo images are only mild to moderately incompetent.
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Mitral dysplasia: Particularly common in cats. Common echo features?
Particularly common in cats. As with TD, the leaflets may be short and thick or elongated. They may be associated with abnormally shaped, elongated or large papillary muscles, and aberrant chordae tendinae with abnormal attachments to the ventricular wall or septum. Although it does occur, the septal leaflet is not usually tethered to the septum as in TD. The valves may display increased echogenicity and abnormal motion secondary to malformation of the mitral apparatur. There may be prolapse and some degree of restricted motion secondary to commissural fusion or abnormal chordae tendinae.
Fig 9.38
