Title: Echocardiographic Assessment of LV Systolic Function
1Echocardiographic Assessment of LV Systolic
Function
2Causes of LV Systolic Dysfunction
- CAD
- HTN
- Cardiomyopathy (iDCM, HCM, Etoh, Peripartum,
Viral, Infiltrative, Toxins, Thyroid Dz.,
Tachyarrythmias) - Valvular Disease
3Dimensions and Area
- Parasternal short-axis at level of papillary
muscles - Parasternal long-axis
- Apical 4-chamber
- Apical 2-chamber
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52D Clips
6LV Mass Quantification
- M-mode
- Area-length method
- Truncated ellipsoid method
- Subjective assessment
7LV Mass Quantification
- 2D M-Mode method using parasternal short axis
view or parasternal long axis view - Assumes that LV is ellipsoid (21 long/short axis
ratio) - Measurements made at end diastole
- ASE approved cube formula
- LV mass (g) 1.04 (LVID PWT IVST)3 -
(LVID)3 - X 0.8
0.6 -
- LV mass index (g/m2) LV mass / BSA
- Small errors in M-Mode cause large errors in mass
values. Can have off axis/tangential cuts due to
motion. -
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9LV Mass Quantification
- Penn convention formula (Another form of the cube
equation) - LV mass 1.04(IVS LVID PWT)3
- (LVID)3 13.6 g
- NL LV mass index for males 93 /- 22 g/m2
- NL LV mass index for females 76 /- 18
g/m2
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11RWT 2(PWT/LVID)
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13LV Volume Measurement With M-Mode
- Assuming nl ventricle morphology
- V (LVID)3
- If ventricle is dilated (spherical)
- Teichholz equation
- Vdiastole 7/(2.4 LVID) x LVID3
14LV Systolic Function Variables
- LVEDD LVESD
- FS -------------------- X 100
- LVEDD
- Percent change in LV dimension with systolic
contraction - FS approximates EF if there are no significant
wall motion abnormalities - SV EDV - ESV
CO SV x HR - EDV - ESV
- EF ----------------- X 100
- EDV
15How do we quantify LV function?
- M-Mode
- Modified Simpsons Method
- Single plane area-length method
- Velocity of Circumferential Shortening
- Mitral Annular Excursion
- E-point to septal separation
- Rate of rise of MR jet
- Index of myocardial performance
- Subjective assessment
16M-Mode Quantification
- Use Parasternal Short-Axis (Mayo) or Long-Axis
(ASE) views to measure LVEDD and LVESD - May take several measurements at different levels
and calculate average - Assumes no significant regional wall motion
abnormalities present. -
17M-Mode Quantification
- Uncorrected (LVEDD)2 - (LVESD)2
- LVEF ----------------------
-------- X 100 -
(LVEDD)2 - If apical contractility is normal (Quinones
group) - Corrected
- LVEF Unc LVEF ((100 Unc LVEF) X
15) - 5 hypokinetic, 0 akinetic, -5 dyskinetic, -10
aneurysm
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19Modified Simpsons Method (Disc Summation
Method)
- Use apical 4 chamber and apical 2 chamber views
to measure dimension and area - Trace borders manually or by acoustic
quantification - Divides area into 20 cylinders of equal height
20Acoustic Quantification
- Automatic detection of blood-tissue border based
on integrated backscatter analysis - This is the difference in amplitude of
backscatter between the myocardial wall and blood - Blood-tissue border is recognized by echo
machine, and marked with dots
21Acoustic Quantification
- Area of study is quantified continuously in real
time throughout cardiac cycle - Therefore, the change in LV cavity area or volume
with systolic contraction is calculated
instantaneously, thereby providing LVEF. - AQ limited by its dependency on echocardiographic
gain and image quality - Echo gain Amplification of the returning RF
signal which weakens with distance i.e. an
increased echodensity is seen as tissue,
thereby decreasing accuracyLateral wall is
especially subject to error.
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23Derivation of 3.14(R)2 X D
24Modified Simpsons Method
- EDV ESV
- LVEF --------------- X 100
- EDV
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26Single plane area-length method
27Velocity of Circumferential shortening
- Vcf is the mean velocity of LV shortening through
the minor axis - Vcf FS/ET
- ET is the time between LV isovolumetric
contraction and isovolumetric relaxation - Measure by obtaining M-mode of AV opening to AV
closure, aortic flow by doppler, or by an
external pulse recording of carotid artery - NL values are gt 1.0 c/s
- Slow Vcf may suggest diminished systolic function
28Mitral Annular Excursion toward LV Apex
- M-mode tracings in systole
- The magnitude of systolic motion is proportional
to the longitudinal shortening of the LV - Normal mitral annular systolic motion is 8mm
(average 12 /- 2 on apical4 or apical 2 views) - If motion is lt 8 mm, the EF is likely lt 50
29Normal E point to septal separation is lt 6
mm With reduced lvef, EPSS may be increased.
30CW doppler to measure rate of rise of MR jet may
correlate to LVEF A slow rate of rise may
indicate poor systolic function Must have MR
present, and good doppler study present (more
difficult with eccentric jets)
31Index of Myocardial Performance (mayo
clinics) Uses systolic and diastolic time
intervals to evaluate global ventricular
performance Systolic dysfunction causes prolonged
isovolumetric contraction time (ICT) and a
shortened ejection time (ET). Systolic and
Diastolic dysfunction causes a prolonged
isovolumetric relaxation time (IRT) IMP (ICT
IRT)/ET
32Index of Myocardial Performance
- Normal LV 0.39 /- 0.05
- LV, DCM 0.59 /- 0.10
- Normal RV 0.28 /- 0.04
- Primary Pulm Htn 0.93 /- 0.34
- Use PW of AV inflow signal, or CW to get AV
regurgitant signal..Also need to measure
interval between AV closure and opening (AVco). - Then, need to use PW or CW to capture semilunar
outflow signal to measure ejection time (ET).
After all of this, IMP can be calculated. - IMP (AVco ET)/ET
33Assessment of Regional Function
- Based on grading wall motion divided into the 16
(17) segment model as proposed by the American
Society of Echocardiography - Each segment can be viewed in multiple
tomographic planes
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38Assessment of Regional Function
- 1 normal
- 2 hypokinesis
- 3 akinesis
- 4 dyskinesis
- 5 aneurysmal
- WMSI Sum of scores / Number of visualized
segments - WMSI gt 1.7 may suggest perfusion defect gt 20
39Assessment of Regional Function
- Qualitative estimation errors due to
- Underestimation of EF due to endocardial
echo dropout - and seeing mostly epicardial motion
- Underestimation of EF with enlarged LV
cavity a large - LV can eject more blood with less
endocardial motion - Overestimation of EF with a small LV cavity
- Significant segmental wall motion
abnormalities
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432D Clips
44Doppler Tissue Imaging for Wall Motion Analysis
- Myocardium is color-coded according to velocity
- On P-Short Axis view, normal LV anterior wall
motion during systole is blue (away from
transducer), and the posterior wall motion is red
(toward transducer) akinesis will have no color -
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46Color Kinesis by 2D-Echo to Evaluate Wall Motion
- Real time color-coded display of LV endocardial
motion on sequential frames - Color is added to pixels that are identified as
changing from blood to tissue in systole - Create a color map of endocardial border
- This method limited by poor endocardial
definition and translational motion of heart.
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48Summary
- LV Mass Quantification M-mode, Area-length
method, Truncated ellipsoid method, and
Subjective assessment. - LV Volume Quantification M-mode, Subjective
assessment - LV Function Quantification Modified Simpsons
and Subjective Assessment by region.Also by
M-mode, Single plane area length method, Velocity
of Circumferential Shortening, Mitral Annular
Excursion, EPSS, Rate of Rise of MR jet, Index of
myocardial performance, etc..
49Summary
- Modalities limited by quality of echo windows,
accurate measurements are based on the ability to
identify and capture ideal axis (recognize
misleading off axis/tangential slices), and of
course, echocardiographer experience..
50Eye Candy
51References
- Oh, Jae K., The Echo Manual 2nd edition, 1999, p.
37-43. - Kerut, Edmund, Handbook of Echo- Doppler
Interpretation, 1996, p. 54-63. - Atlas of Echocardiography Website
- Braunwald, Eugene, Heart Disease 6th edition, p.
165-169.