Systolic Function

Question 1

Classes of segmental LV systolic function

Answer 1

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

Question 2

Coronary blood flow distribution

Answer 2

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

Question 3

Fractional shortening

Answer 3

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

Question 4

Fractional Area Change

Answer 4

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

Question 5

Ejection Fraction

Answer 5

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

Question 6

Stroke Volume

Answer 6

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

Question 7

Qp / Qs

Answer 7

Qp / Qs = SV pa / SV lvot

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

Question 8

LV Hypertrophy Measurements

Answer 8

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

Question 9

Dp / Dt

Answer 9

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

Question 10

Velocity of Circumferential Shortening

Answer 10

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

Question 11

End Systolic Elastance

Answer 11

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

Question 12

Preload recruitable stroke work

Answer 12

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

Question 13

Preload adjusted max power

Answer 13

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

• load independent
• mostly for research purposes

Question 14

Strain rate

Answer 14

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

Question 15

Tissue doppler peak systolic velocity

Answer 15

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

Question 16

Load independent measures of systolic function

Answer 16

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