Systolic Function Flashcards

1
Q

Classes of segmental LV systolic function

A

Class — radial shortening — thickening
Normal. > 30% +++
Mild. 10 - 30% ++
Severe. 0 - 10%. +
Akinesis. 0. 0
Dyskinesis. Lengthening. Thinning.

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2
Q

Coronary blood flow distribution

A

RCA only —> RV, basal inferoseptal, inferior (75% right dominant)

LAD only —> apex, anterior, anteroseptal

No segment perfused by Cx only!

RCA/LAD —> mid inferoseptal

RCA/Cx —> inferolateral

LAD/Cx —> anterolateral

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3
Q

Fractional shortening

A

FS = (LVEDd - LVESd) / LVEDd
•Normal > 30%
•Measured just beyond MV at chordal level perpendicular to LAX of LV using M-mode (exclude the papillary muscles)
•TG2C @ 90 deg OR TG Mid @ 0 deg

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4
Q

Fractional Area Change

A

FAC = (EDA - ESA) / EDA
•Normal > 50%
•TG Mid SAX view (include papillary muscles)

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5
Q

Ejection Fraction

A

EF = (EDV - ESV) / EDV
•Normal > 55%
•Simpson’s MOD
•Dependent on : preload, afterload, contractility

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6
Q

Stroke Volume

A

SV = CSA x VTI

•CO = SV x HR
Calculated at LVOT or AV

Accuracy dependent on:
•parallel alignment of u/s beam to blood flow
•accurate determinations of vessel CSA

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7
Q

Qp / Qs

A

Qp / Qs = SV pa / SV lvot

SV pa = A pa x VTI pa
SV lvot = A lvot x VTI lvot

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8
Q

LV Hypertrophy Measurements

A

Degree LVH. Septal/IL(M).Septal/IL(W)
Normal. 6-10 mm. 6-9 mm
Mild. 11-13 mm. 10-12 mm
Moderate. 14-16 mm. 13-15 mm
Severe. > 17 mm. > 16 mm

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9
Q

Dp / Dt

A
Isovolumetric rate of LV pressure rise
Dp/Dt = 32 / Dt
•calculated as slope of LV pressure rise from 4-36 mmHg (Vmr = 1 to Vmr = 3)
•assumes the LAP doesn’t change
•Dt = time from 1 m/s to 3 m/s
Steeper the slope the faster the pressure increases and better systolic function
•normal = 1300+
•Independent of afterload
•Dependent on preload
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10
Q

Velocity of Circumferential Shortening

A

VCF = (LVEDd - LVESd) / (LVEDd x ET)
•Fractional shortening with the ejection time in the denominator
•Less preload dependent than EF but still load dependent
•doppler profile at AV to measure ejection time or use M-mode and measure time that AV is open

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11
Q

End Systolic Elastance

A

Slope of pressure-volume curve
•true load independent measure of contractility and systolic function
•used mainly in research
•steeper the slope the better the end systolic elastance and better the systolic function
•measured by occluding the IVC to change loading conditions

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12
Q

Preload recruitable stroke work

A

Slope of stroke work as a function of EDV
•steeper the slope the better the systolic function
•load independent measure
•true index of contractility

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13
Q

Preload adjusted max power

A

= stroke work / EDV^2
= stroke work / EDA^3/2

  • load independent
  • mostly for research purposes
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14
Q

Strain rate

A

Strain rate = Strain / Dt = (V1-V2)/x
•Change in length produced by the application of stress over time
•measured using TDI — velocity at V1 and V2 with x the distance between
•angle dependent measurements
•can be used for dysynchronous wall motion
•speckle tracking is independent of angles because no doppler being used

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15
Q

Tissue doppler peak systolic velocity

A

PWD at MV annulus
•faster the systolic velocity the better the systolic function
•normal values vary

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16
Q

Load independent measures of systolic function

A

End-systolic elastance
Preload recruitable stroke work
Preload adjusted max power
Strain rate