Ventricular Systolic Function Flashcards

1
Q

What are the ventricle systolic functions? (3)

A
  1. Systemic - LV pump blood to body
  2. Pulmonary - RV pump blood to lungs
  3. Adequate perfusion
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2
Q

What is the basis of systolic dysfunction?

A

Inability to contract

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3
Q

What produces ventricular systole?

A

Depolarization of the ventricles followed by contraction

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4
Q

How does contraction affect pressure in the ventricles?

A

Increases it

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5
Q

What are the phases of systole?

A
  1. IVCT (Isovolumic Contraction Time) - Valves closed pressure building
  2. Ventricular Ejection - AV valves closed, semi-lunar open due to pressure gradient
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6
Q

When does IVCT occur?

A

Onset of QRS

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7
Q

What are the intracardiac pressures for the LV?

A
Sys = 120 mmHg
Dia = 10 mmHg
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8
Q

What are the intracardiac pressures for the LA?

A

Mean = 10 mmHg

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9
Q

What are the intracardiac pressures for the RV?

A
Sys = 25 mmHg
Dia = 4 mmHg
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10
Q

What are the intracardiac pressures for the AO?

A
Sys = 120 mmHg
Dia = 70 mmHg
Mean = 85 mmHg
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11
Q

What are the intracardiac pressures for the PA?

A
Sys = 25 mmHg
Dia = 10 mmHg
Mean = 16 mmHg
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12
Q

Describe the sequence of the pressure/volume relationship through the cardiac cycle in the LV/RV (9 steps)

A
  1. Depolarization of LV/RV
  2. Contraction
  3. Increased pressure
  4. Pressure exceeds AO/PA
  5. AO/PA open
  6. Ejection
  7. Decreased pressure
  8. AO/PA close
  9. Pressure falls until MV/TV open
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13
Q

What is the pressure-volume loop?

A

A display of the pressure/volume relation ship on a graph where pressure climbs during contraction (IVC), equalizes during ejection(systole), falls during relaxation (IVR) and equalizes during Diastole.

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14
Q

What is the difference between the pressure/volume loop in the RV and LV?

A

In the LV the loop is square and in the RV it is triangular due to lower pressures, lower impedance of the vascular bed and flow continuing to enter the PA after the peak pressure is reached in the right heart.

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15
Q

What is preload?

A

The muscle stretch due to volume increase at the end-diastole before contraction.

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16
Q

What is afterload?

A

The tension/load that the LV must eject or overcome before fiber shortening occurs

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17
Q

How can we measure preload?

A

We can only estimate it by using:

  • LVEDV or RVEDV
  • LVEDP or RVEDP
  • LA or RA Pressure
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18
Q

How are preload, EDV and SV all related?

A

They are all directly related.

An increase in preload will increase the end-diastolic volume which will increase the stroke volume.

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19
Q

What is stroke volume?

A

The amount of blood pumped out of the LV or RV in one systolic contraction.

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20
Q

What factors affect afterload? (3)

A
  • Ventricular volume
  • Vascular resistance (blood pressure in the Ao or PA)
  • Wall thickness
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21
Q

Which ventricle is more resistant to afterload?

A

The RV

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22
Q

How is afterload related to ESV and SV?

A

Changes in afterload affect the ability of the ventricles to contract therefore if the afterload increases, the SV decreases and the ESV increases (blood left in ventricle).

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23
Q

What is another name for inotropy?

A

Contractility

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24
Q

What does inotropy/contractility mean?

A

The strength of the cardiac muscle and its ability to shorten with contraction.

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25
Q

Do preload, afterload and inotropy affect eachother?

A

Yes, a change to either afterload, preload or inotropy/contractility will affect the other two also.

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26
Q

What factors increase SV? (3)

A
  1. Increased preload
  2. Decreased afterload
  3. Increased inotropy/contractility
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27
Q

What factors decrease SV?

A
  1. Decreased preload
  2. Increased afterload
  3. Decreased inotropy
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28
Q

How is the the LV systolic function measured qualitatively?

A
  1. Visual kinetic analysis
  2. Segmental wall motion analysis:
    - Normal
    - Hypokinetic
    - Akinetic
    - Dyskinetic
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29
Q

What methods can be used to quantitively assess systolic function? (9)

A
  • Fractional shortening
  • Ejection fraction (linear)

Volumetric:

  • Simpson’s
  • Area length method
  • SV/CO/CI
  • Dp/Dt
  • Tissue Doppler (s prime)
  • MPI
  • Global Strain (GS)
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30
Q

What is another name for linear EF?

A

Teicholz

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31
Q

What is EF?

A

Ejection Fraction is the percentage of LV volume that is ejected with systole

32
Q

What is the normal value for PLAX/Teicholz EF?

A

Greater than or equal to 55%

33
Q

What is the formula for PLAX/Teicholz EF?

A

(LVEDV-LVESV/LVEDV) x 100

34
Q

How can PLAX/Teicholz EF be assessed and what method is more accurate?

A

M-mode or 2D

2D more accurate

35
Q

What is fractional shortening?

A

The percentage of change in the minor axis of the LV with systole

36
Q

What is the formula for FS?

A

FS = (LVEDD - LVESD)/LVEDD x 100

37
Q

What is the normal value for FS?

A

25-45%

38
Q

When should end-diastole be measured on 2D or m-mode?

A

Iso-Volumic Contraction Time (onset of QRS)

39
Q

When should End-systole be measured on 2D or M-mode?

A

Iso-Volumic Relaxation Time (End of T wave)

40
Q

The measurements taken at the base of the LV in the PLAX routine are used to determine what?

A

EF (Teicholz) and FS

41
Q

What is another name for the Simpson’s biplane method?

A

Method of disks

42
Q

How is Simpson’s done?

A

Tracing the endocardium during diastole and systole in both 4AC and 2AC

43
Q

When should you not use simpsons?

A

When you don’t have clear endocardial definition or when the ventricle is foreshortened (cannot see apex).

44
Q

What should the Simpson’s central axis extend between?

A

The MV annulus and the true LV apex

45
Q

When doing simpson’s can the LV axis length differ between the A2C and A4C view?

A

It can but it must not differ more than 10%

46
Q

How can we determine the SV and EF from Simpson’s and what are the formulas?

A

By finding the ESV and EDV by averaging the A4C and A2C dimensions

SV = EDV - ESV

EF = (EDV^3 - ESV^3)/ EDV^3x 100

47
Q

How can CO be determined and what do you need to be given? (2 steps)

A

Must have HR

  1. Derive the SV either from Simpson’s (EDV - ESV) or VTI (CSA x VTI)
  2. CO = SV x HR
48
Q

When is the Area- Length method used?

A

To calculate LV volume when the endocardium cannot be well defined in apical views

49
Q

What is needed to use the Area Length method to find LV volume?

A
  1. A trace of the LV in PSAX at pap level

2. A LV length measurement from MV to apex in A4C

50
Q

What is the normal value for Fractional Shortening and what is severe?

A

Normal = 25 - 45 %

Severe = ≤ 14

51
Q

What is the normal value for PLAX/Teicholz EF and what is severe?

A

Normal = ≥ 55%

Severe = ≤ 30 %

52
Q

What is the normal value for LV size in cm and what is considered severe?

A

Normal = ≤ 5.9 cm

Severe= ≥ 6.9 cm

53
Q

What is the normal value for Simpson’s EF (women and men) and what is considered severe?

A

Women normal = 54-74 %

Men normal = 52-72 %

Severe = ≤ 30 %

54
Q

What is Dp/Dt?

A

Dp/Dt is a rate of LV pressure rise during IVCT where Dp is the change in pressure and Dt is the time taken for the change to happen.

55
Q

Why is Dp/Dt useful?

A

When mitral regurg and impaired LV contractility occur together the EF can appear normal due to the increased preload from the MR even though the inotropy is worse. Dp/Dt is not affected by preload and therefore is better to assess LV systolic function in this case.

56
Q

How do you measure dP/dt? (5 steps)

A
  1. CW mitral regurg jet
  2. Choose two points (1 and 3 m/s)
  3. Draw line along jet between the points to calc the time change
  4. Use bernoulli to find the pressure at each point (P=4v^2)
  5. Find the difference between the two pressures
  6. Divide the pressure difference by the time difference to find the rate of pressure rise
57
Q

What are the limitations of Dp/dt? (2)

A
  1. LA pressure must be constant (In acute MR the LA may not be compliant because it has not adapted to accept the extra blood and therefore cannot accept the volume without rising its pressure).
  2. Anything that poorly affects the CW MR jet (valve clicks, eccentric jets, poor doppler alignment to MR jet)
58
Q

What is the normal value for dP/dt and what is severe?

A

Normal = > 1200

Severe = < 800

59
Q

What is the normal time for the LV to generate 32 mmHg and what is severe? (Dp/dt)

A

Normal = <27 ms

Severe = >40 ms

60
Q

What is TDI?

A

Tissue doppler imaging is a way of assessing LV systolic function by measuring the speed that the LV contracts in the longitudinal plane (apical views).

61
Q

What are the waves of TDI?

A

S prime = Apex directed velocity (systole)

E prime = Atria directed velocity (early diastole)

A prime = Atria directed velocity (late diastole)

62
Q

What is S prime influenced by and how does this factor affect its accuracy?

A

S prime is influenced by tethering and translational motion which affects its accuracy in cases of varying degrees of segmental dysfunction as it will not include those abnormal segments.

63
Q

When is S prime used in the routine and what is the normal value?

A

Used on RV annulus in A4C

Normal = > 9.5 cm/s

64
Q

What is MPI?

A

A ratio between IVCT and IVRT divided by the ejection time that provides info on the “global” myocardial performance (both systole and diastole)

65
Q

What is RIMP and LIMP?

A

RIMP = MPI done on RV

LIMP = MPI done on LV

66
Q

What is the formula for MPI?

A

MPI = (IVCT + IVRT)/ET (ejection time)

67
Q

What is the normal value for RV MPI (RIMP)?

A

< 0.44

68
Q

When is MPI used?

A

Cases of systolic and diastolic dysfunction coexisting:

  1. Dilated cardiomyopathy
  2. Cardiac amyloidosis
  3. Pulmonary hypertension
  4. RV infarction
  5. RV dysplasia
69
Q

Describe the differing qualitative sizes/dilation of the RV.

A

Normal = Less than 2/3 of LV and LV dominates apex

Mild dilation = RV > 2/3 of LV but still smaller and RV apex closer to base than LV

Moderate dilation = RV = LV and spex is shared

Severe = RV>LV and RV dominates apex

70
Q

What is TAPSE?

A

Measurement of the RV systolic function in longitudinal plane (how much the annulus moves towards apex in systole)

71
Q

What is the normal value of TAPSE?

A

≥ 17 mm

72
Q

What is the fractional area change?

A

A method of assessing the RV systolic function by tracing the RV in systole and diastole in 4AC and using the FAC formula

73
Q

What is the FAC formula?

A

[(EDA - ESA) / EDA] x 100

74
Q

What is the NV for fractional area change?

A

Less than 35%

75
Q

What are the 4 ways to assess RV systolic function?

A
  1. S prime TDI
  2. TAPSE
  3. Fractional area change
  4. RV MPI (RIMP)