Transcript Assessment of LV Systolic Function

Assessment of LV Systolic
Function
Dr Nithin P G
Overview
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Normal LV contraction
Global & regional indices of LV systolic Function
Angiographic assessments
Echocardiography
MRI
Computed Tomography
Nuclear Imaging
Take home message
Introduction
• Mechanical pump
• LV systolic function = Contractility
Normal contraction of LV
J Am Coll Cardiol Img 2008;1:366 –76
ASSESSMENT OF LV FUNCTION
Clinically relevant indicators of global
LV function
EJECTION FRACTION.
• Ratio of SV to EDV. [EDV-ESV/EDV]
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Simplicity of its derivation
Ability to determine easily
Reproducibility using different imaging techniques
Extensive documentation of its clinical usefulness.
Ejection fraction
Drawbacks
– Depends on preload and afterload, as well as HR and synchronicity of
contraction.
Preload increases [AR,MR,
Anemia]
EF increases
Afterload increases [AS]
EF decreases
– Global parameter, major regional differences in contractility are presented as an
average
– Given EF may have different prognostic importance according to clinical
situation eg severe MR
Hemodynamic measurements
• Cardiac index (liter/min/m2) = HR × SV/BSA
• Stroke Volume index (ml/m2) = SV/BSA
• Stroke Work index (ml×mmHg/m2) = SVI × mean SBP
– LVSW reasonably good measure of LV contraction ,exceptions
• Volume or Pressure overload
• RWMA
ESPVR
ESPVR or maximum elastance- method for LV contractility
• Nearly independent of preload and afterload
• Multielectrode catheters –impedance, Vol., micromanometer Pressure
recordings [aortic dicrotic notch pressure as ESPr & Minimum LV chamber
volume ]
• Pacing/ IVC balloon occlusion/ Drugs  PV loops at different loads 
line drawn across ES points
• Slope of line = measure of LV contractility
ESPVR
• ESPVR accurately reflect myocardial contractility independent of
ventricular loading [ in various canine and human studies]
• Drawbacks
• Difficult to perform
• Invasive
• Spontaneous variability over the time it takes to make
measurements
• Curves dependent on gender, age, position of IVS [RV filling
pressure, LBBB]
MAXIMAL RATE OF PRESSURE RISE
• Maximum rate of rise of LV Sys. Pr. [IVC]
• Analogous to the maximal rate of tension development of isolated
cardiac muscle [well-established index of myocardial contractility]
• Relatively load independent [ changes to afterload & preload < 10%
in normal physiological limits]
Drawbacks
•Comparison b/w individuals
difficult
•c/c AS dP/dt less when
contractility normal
•RWMA & marked dyssynchrony
Regional Indices of Left Ventricular
Function
• WMS [wall motion score]
• Center line chordal shortening
• Radian change, regional area change
• Strain rate imaging
• Torsion imaging
Centerline method
ANGIOGRAPHIC ASSESSMENT
Volume calculations
V= 4/3 p [L/2] [M/2] [N/2] = p /6 LMN
ARAO= p [LRAO/2] [ M/2]= p [LRAO][M]/4
ALAO= p [LLAO/2] [N/2]= p [LLAO][N]/4
V= p /6 Lmax [4ARAO] [4ALAO]
[p LRAO][p LLAO]
Usu, Lmax= LRAO
=> V= 8 ARAO ALAO
3 p LLAO
Regional indices
Angiographic wall motion score
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1= normal
2= moderate hypokinesis
3=severe hypokinesis
4=akinesis
5=aneurysm/dyskinesis
• Normal score is 5
ECHOCARDIOGRAPHY
Assesment by Echocardiography
Ejection Fraction
1. M- mode
• EF= LVEDD2-LVESD2 x100
LVEDD2
• EFc= [(1-%EF) x % DL] + %EF
DL=apex contractility
15% normal
5% hypokinetic
0% akinetic
-5% dyskinetic
-10% aneurysmal
– Only along a single interrogation line, regional variation in function
– Does not reflect true minor axis especcially in elderly with angulation
Ejection fraction
2. D3 method
L
D1
D2
Vol = 4/3 p (D1/2) (D2/2) ( L/2)
= 4/3 p (D1/2) (D1/2) ( 2D1/2)
= p/3 (D3)
= 1.047 D3
= D3
More spherical shape,
Vol. = (7/2.4+D) x D3
Ejection fraction
3. Modified Simpson’s biplane
method [2D-Echo]
• Vol= p/4 S ai bi L
i=1
20
20
[Difference b/w ai & bi should be less
than 20%]
• Most reliable method in case of
regional difference in function
• EF calculated comparable to those
measured hemodynamically
Ejection Fraction
4. Single plane Area- length Method
• When only one view is available
• Ventricle is considered symmetrical
• Vol= 0.85 A2
L
Other parameters
• Fractional Shortening
FS= LVEDD-LVESD x100
LVEDD
• Velocity of Circumferential Fiber shortening [Vcf]
Mean Vcf= FS/ LVET
– Mean velocity of ventricular shortening of the minor axis of LV
– Ejection phase index of systolic function
Other parameters
• Myocardial Performance
index [TEI index]
ICT + IRT
ET
– Measure of both sys &
diastolic function
– Normal <0.4
– Strong inverse relationship
with EF
– Independent of ventricular
geometry
Hellenic J Cardiol 2009; 50: 60-6
Other parameters
M- mode parameters
• EPSS
– >6mm abnormal
• Descent of base
– Linear correlation b/w
magnitude of annular
excursion & LV function
• Rounded appearance of aortic
valve closure in late systole
• Rates of systolic thickening of
PW
Regional function indices
• WMS
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Normal =1
Hypo=2
Akinetic=3
Dyskinetic=4
• WMSI
S WMS/N
Deformation analysis
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Newer methods of TDI & speckle tracking
Analysis of strain, strain rate or torsion
Strain- L-L0/L0
Strain rate- velocity of change over time
Deformation analysis
Drawbacks
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Strain not uniform from base to apex & in circumferential plane [anterior &
lateral wall higher]
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Angle dependency
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Preload dependent
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Heterogenicity within the same myocardium
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Patient to patient variability
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Inter & Intra observer variability
APEX
2-D Echo evaluation of LV Function
• Most common method used is Simpson’s rule
• Most accurate when LV geometry is normal
• Correlation coefficients ~ 0.75 compared to RNA, cine
angiography & autopsy studies Circulation 1979, 60:760-766;
Circulation 1980, 61:1119-112
• Limited by reproducibility b/w individual studies
• Improved by tissue harmonic imaging & contrast use.
3D Echocardiography
• Direct evaluation of cardiac chamber volumes without the
need for geometric modelling and without the detrimental
effects of foreshortened views
• Direct 3D assessment of regional LV wall motion
• Quantification of systolic asynchrony to guide CRT
• 3D color Doppler imaging with volumetric quantification of
regurgitant lesions , shunts , and cardiac output
J Am Coll Cardiol 2006; 48:2053– 69
3D Echocardiography
Am J Cardiol 2005;95:809–813
MAGNETIC RESONANCE IMAGING
MRI
• Gold standard for assessing LV & RV function
Parameters
Comments
Global Function
LVEF
LV ESV, LV EDV
‘Gold standard’
•Simpson’s rule & A-L method
•Steady state free precession [SSPE]
•Even in patients with abnormal geometry
•Low inter & intra observer variability
Cardiol Clin 25 (2007) 15–33
Regional Function
RWMA
Tissue tagging
Displacement encoding [DENSE}
Wall thickening
Center line method
Tissue tagging
LV Strain
Tissue tagging
DENSE
MRI
Assessment by MRI
Gradient echo images of sequential multiple slices of the left ventricle in short-axis
planes (from base to apex) are displayed for determining left ventricle volume
by Simpson’s rule
Cardiol Clin 25 (2007) 15–33
Assessment by MRI
Tagging of Ventricle for detection of RWMA Radiology 2004;233:210–6
2-D displacement Map & Colour coded myocardial strain map
Radiology 2004:230:862–71
COMPUTED TOMOGRAPHY
Computed Tomography
• EBCT & MDCT has excellent visualization of cardiac
structures.
• Delineation of epicardial & endocardial borders allow accurate
& reproducible measure of wall thickness, ESV, EDV.
• ECG gating & image post processing allows cine mode
imaging
ECG gated CT
Computed Tomography
Global Function
Regional Function
Parameters
Comments
LVEF
LV ESV, LV EDV
Comparable to RNA Am J
Cardiology 1999; 83 (7): 1022-1026
Wall Motion Abnormalities and Stress rest EBCT comparable to Tc
SPECT for detecting CAD [EF- 81,
Wall thickening
76; EF+RWMA- 88, 100] Am J
Cardiology 1998; 81 (6): 682-687
Ventricular Remodeling
Comparable to SPECT &
Echocardiography J Comput Assist
Tomogr 2006; 30 (4): 555-563
Computed Tomography
MRI [Gold Standard] >
MDCT>2D-Echo &
SPECT
Radiology 2005; 234:381–390
Computed Tomography
• Disadvantages
– Radiation risk
– Contrast toxicity
– Temporal resolution comparably limited
• Used when echo window very poor & MRI contraindicated
NUCLEAR IMAGING
Radionuclide Angiography
• Equilibrium method
– ECG gated, data averaged from multiple cardiac cycles, MUGA
– 99mTc labeled RBC
• First- pass method
– Dynamic acquisition, rapid temporal sampling to look at initial
transit
• Principal application is measurement of LVEF
– ICD, ACEI use, Surgical ventricular restoration, Cardiotoxic
chemotherapeutics ( Adrimycin therapeutics), Heart Failure
Trials
SPECT
Parameters
Global Function
LVEF
LV ESV, LV EDV
Regional Function
Wall Motion, Wall Thickening
Comments
LV contraction Histogram
Dysynchrony- heterogenous
phase angle distribution
Lung to Heart Ratio
Increased lung uptake =
incrased PCWP also in MS,MR
Transient Ischemic Dilation Ratio
Apparent cavity dilation 20 to
diffuse subendocardial
ischemia
LV eccentricity & Shape Index
SPECT
LV contraction Histogram
SPECT
Prognostic Value of Lung Sestamibi Uptake in Myocardial Perfusion Imaging of
Patients With Known or Suspected Coronary Artery Disease
Overall (n =
718)
Normal (n =
367) SSS<3
Mild (n = 136)
SSS 4-8
Moderate (n
= 78) SSS 9-13
Severe (n
=137) SSS>13
Stress LHR
0.32±0.06
0.30±0.05
0.31±0.05
0.34±0.08
0.36±0.07
Rest LHR
0.31±0.06
0.30±0.05
0.31±0.05
0.32±0.07
0.35±0.06
Diff. LHR
0.006±0.05
0.003±0.046
0.000±0.048
0.017±0.065
0.012±0.053
p value:
sLHR vs. rLHR
0.001
0.15
>0.2
0.02
0.008
J Am Coll Cardiol, 2005; 45:1676-1682
SPECT
Take Home message
• 2D Echo- most common
• MRI- precision, complex
geometry
• Nuclear imaging, CT- used
when other indications
present
J Am Coll Cardiol Img 2008;1:652–62
Thank you