Module 2 : Ventricular Systolic Function Flashcards
(97 cards)
1
Q
LV function - systole
A
- ventricles pump blood into systemic and pulmonary circulation
- ensures adequate perfusion to the body
2
Q
what is systolic dysfunction
A
- inability to contract
3
Q
what 3 things does an inability to contract lead to
A
- decrease in SV/EF
- increased preload (LVEDP)
- ? congestive heart failure
4
Q
LV function - diastole
A
- ventricular distention/ relaxation
- to be able to fill up to prepare for the next contraction
5
Q
what is starlings law
A
- as filling occurs stretch in muscle develops tension/strength for contraction
6
Q
what type of pressure gradient does diastole create
A
- negative pressure gradient to ensure venous return
7
Q
what stage do the coronary arteries fill
A
- diastole
8
Q
how is ventricular systole produced
A
- by depolarization of the ventricles followed by mechanical contraction
- ventricular myocardium contraction produces increased pressure within LV and RV
9
Q
2 phases of systole
A
- isovolumic contraction
- ventricular ejection
10
Q
what is isovolumic contraction
A
- all valves closed
- ventricular pressure is building up
11
Q
what is ventricular ejection
A
- atrio-ventricular valves closed
- semilunar valves open caused by pressure gradient between LV and aorta
- ejection occurs until ventricular pressure equalizes with the great vessels
12
Q
systole sequence
A
- myocardial depolarization»_space; contraction» ejection
- as pressure increases»_space; reduction of the internal volume of the chamber
13
Q
timing of systole
A
- IVCT = onset of QRS
- ejection = starts when AV opens ends when AV closes
14
Q
systolic, diastolic, mean pressure in AO
A
- sys = 120mmHh
- dia = 70mmHg
- mean = 85mmHg
15
Q
systolic, diastolic, mean pressure in PA
A
- sys = 25mmHg
- dia = 10mmHg
- mean = 16mmHg
16
Q
mean LA pressure
A
- 10mmHg
17
Q
systolic and diastolic LV pressure
A
- sys = 120mmHg
- dia = 10mmHg
18
Q
systolic and diastolic pressure RV
A
- sys = 25mmHg
- dia = 4 mmHg
19
Q
mean RA pressure
A
- 4mmHg
20
Q
5 steps of the ventricular pressure - volume relationship
A
- after depolarization of the ventricular muscle the LV/RV starts to contract
- contraction increases the intra-cavitary pressure
- pressure rises until it exceeds aortic/pa pressure which opens the AV/PV and blood is ejeceted
- after ejection LV/RV pressure falls below that of the aorta and pA which closes the AV PV
- pressure keeps falling during relaxation until MV and TV openm
21
Q
what shape is the pressure loop for the LV and the RV and why
A
- LV = retangular
- RV = triangular
- lower right heart pressures
- lower impedance of the pulmonary vascular bed
22
Q
three determinants of stroke volume
A
- preload
- afterload
- contractility
23
Q
what is preload
A
- muscle length or stretch at end diastole
24
Q
how do we estimate preload
A
- LVEDP = left ventricle end diastolic pressure
- PVEDP = pulmonary vein EDP
- LA pressure
25
what is after load
- the tension that the LV must overcome before fibre shortening and contraction
26
what three things affect after load
- changes in ventricular volume
- wall thickness
- vascular resistance
27
what is after load most often determined by
- SVR = systemic vascular resistance or blood pressure
28
is the RV or the LV more sensitive to after load
- RV
29
what is contractility
- aka inotropy
| - inherent strength of the cardiac muscle and ability to shorten as contracts
30
what three factors increase stroke volume
- increase preload
- decrease afterload
- increase inotropy
31
quantitative systolic measurements
- fractional shortening FS
| - ejection fraction EF
32
7 volumetric assessments of systolic measurement
- simpsons EF
- area length method
- stroke volume / CO / CI
- Dp/Dt
- tissue doppler
- MPI
- global strain
33
2 qualitative assessment of systolic function
- visual kinetic analysis (global EF estimation)
| - segmental wall motion analysis
34
4 types of wall motion
- normal
- hypokinetic
- akinetic
- dyskinetic
35
teicholz ejection fraction
- LVIDd ^3 - LVIDs^3 / LVID^3 x 100
36
normal parasternal techolz EF
>/= 55%
37
fractional shortening equation
FS = LVIDd - LVIDs / LVIDd x 100
38
normal FS
> 25%
39
what does teicholz EF need to be accurate
- needs to have symmetrical contractility
40
what is fractional shortening
- % of change in the minor axis dimension
| - has a correlation to EF
41
normal simpsons EF for male and female
```
male = 52-72
female = 54-74
```
42
3 signs of end diastole
- onset of QRS complex
- frame after MV closure
- frame where the LV diameter/dimension is largest
43
3 signs of end systole
- the frame proceeding MV opening
- when the LV is smallest
- near the end of the T wave
44
how to measure LVID with abnormal IVS
- when peak downward displacement of the septum is abnormal use the peak upward displacement of the posterior wall for timing
45
2 things needed for simpsons EF
- requires clear endocardial definition
| - reduce depth to half way into th atria and sector down if possible
46
when would you never do Simpsons
- suboptimal endocardial definition
| - IF YOU CANNOT SEE TWO ADJACENT SEGMENTS
47
how do we quantify left ventricle volumes
- end diastolic trace (A4C and A2C average)
| - end systolic trace (A4C and A2C average)
48
stroke volume equation with EDV and ESV
SV = EDV - ESV
49
severe abnormal parasternal teichols EF
= 30
50
normal LV size women
= 5.3
51
severe abnormal LV size women
>/= 6.2
52
normal LV size men
= 5.9
53
severe abnormal LV size men
>/= 6,9
54
normal simpsons EF female
54-74
55
severe abnormal simpsons EF female
< 30
56
normal simpsons EF male
52-72
57
severe abnormal Ef male
< 30
58
4 tips/assumptions for SV calc
- accurate LVOT measurement
+ assumes LVOT is circular
- Laminar flow assumed
+ plate sv in center of LVOT
- parallel intercept angle between doppler beam and direction of flow
- velocity and diameter measurements are made at the same anatomic site
59
pressure over time equation
Dp/Dt
| - Dp will ALWAYS equal 32mmHg
60
when is Dp/Dt measured
- the pre-ejection phase fo the cardiac cycle
| - less influenced by loading conditions
61
what is Dp/Dt a measurement of
- rate of LV pressure rise during isovolumic contraction
62
what are the two arbitrary points chosen for Dp/Dt
1m/s and 3m/s
63
4 limitations of Dp/Dt
- valve click artifacts (prosthetic valves)
- eccentric MR jets (difficult to pick up CW)
- poor alignment to MR jets
- non compliant LA
64
how to do Dp/Dt
- optimize mitral regurge jet
- increase sweep speed to 100-200 cm/s
- draw a line from 1m/s to 3m/s
65
normal Dt
< 27 milisec
66
severe abnormal Dt
> 40ms
67
normal Dp/Dt values
> 1200 mmHg/s
68
severe abnormal Dp/Dt
< 800 mmHg/s
69
how are the muscle tissue in the LV arranged
- longitudinally
- radially
- circumferentially
70
what does tissue doppler measure
- speed that the LV muscle contracts in the longitudinal plane
- good measure of systolic function
71
what is normal LV s prime measurement
> 9.0cm/s
72
what is normal RV s prime measurement
> 9.5cm/s
73
6 s prime limitations
- can only truly reflect the performance of the basal segments in apical view
- if wall motion normal or globally down s prime will still be accurate
- if there are varying degrees of segmental systolic dysfunction s prime not as accurate
- s prime is influenced by tethering and translational motion of heart
- s prime velocity progressively decrease from base to apex
- TDI requires the optimal doppler angle
74
LIMP
- left index of myocardial performance
75
RIMP
- right index of myocardial performance
76
5 cases where index of myocardial performance is used
- dilated cardiomyopathy
- cardiac amyloidosis
- pulmonary hypertension
- RV infarction
- RV dysplasia
77
can MPI provide info on systolic and diastolic function
- yes
78
what is IMP a ration between
- isovolumic contraction time and isovolumic relaxation time divided by ejection time
79
normal LV LIMP doppler method
< 0.44
80
TDI MPI method LV normal LIMP
< 0.6
81
TDI MPI method RV normal RIMP
< 0.55
82
how is the RV size assessed
qualitatively
83
normal RV size - qualitative
- RV in A4C view should be less than 2/3 size of LV
| - LV should dominate apex
84
Mild dilation of RV size - qualitative
- RV > 2/3 of LV but RV cavity is still smaller than LV
| - RV apex more basal than LV apex as normal
85
moderate dilatation of RV - qualitative
- RV and LV share apex
86
severe dilatation of RV - qualitative
- RV > LV size
| - RV occupies the apex
87
normal RV basal diameter
= 4.1 cm
88
normal mid cavity diameter RV
= 3.5cm
89
normal RV length
=8.6cm
90
RVOT diameter normal prox
= 3.3 cm
91
RVOT diameter normal distal
= 2.7cm
92
normal RV fractional area change
>/= 35%
93
normal MPI RV doppler method
= 0.43
94
TAPSE normal
>/= 12mm
95
5 methods to asses RV systolic function
- TASPSE
- RV s prime wave
- RV fractional area change
- RIMP
- RV stroke volume
96
what 3 things is RV stroke volume dependant on
- preload
- afterload
- contractility
97
qualitative LV systolic function assessment
- need to assess wall motion and thickening
| - walls must be seen in 2 or more views to be scored
