Systolic Function Flashcards
Classes of segmental LV systolic function
Class — radial shortening — thickening
Normal. > 30% +++
Mild. 10 - 30% ++
Severe. 0 - 10%. +
Akinesis. 0. 0
Dyskinesis. Lengthening. Thinning.
Coronary blood flow distribution
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
Fractional shortening
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
Fractional Area Change
FAC = (EDA - ESA) / EDA
•Normal > 50%
•TG Mid SAX view (include papillary muscles)
Ejection Fraction
EF = (EDV - ESV) / EDV
•Normal > 55%
•Simpson’s MOD
•Dependent on : preload, afterload, contractility
Stroke Volume
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
Qp / Qs
Qp / Qs = SV pa / SV lvot
SV pa = A pa x VTI pa
SV lvot = A lvot x VTI lvot
LV Hypertrophy Measurements
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
Dp / Dt
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
Velocity of Circumferential Shortening
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
End Systolic Elastance
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
Preload recruitable stroke work
Slope of stroke work as a function of EDV
•steeper the slope the better the systolic function
•load independent measure
•true index of contractility
Preload adjusted max power
= stroke work / EDV^2
= stroke work / EDA^3/2
- load independent
- mostly for research purposes
Strain rate
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
Tissue doppler peak systolic velocity
PWD at MV annulus
•faster the systolic velocity the better the systolic function
•normal values vary