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Assessment of LV Systolic Function

Assessment of LV Systolic Function. Dr Nithin P G. Overview. Normal LV contraction Global & regional indices of LV systolic Function Angiographic assessments Echocardiography MRI Computed Tomography Nuclear Imaging Take home message. Introduction. Mechanical pump

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Assessment of LV Systolic Function

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  1. Assessment of LV Systolic Function Dr Nithin P G

  2. Overview • Normal LV contraction • Global & regional indices of LV systolic Function • Angiographic assessments • Echocardiography • MRI • Computed Tomography • Nuclear Imaging • Take home message

  3. Introduction • Mechanical pump • LV systolic function = Contractility

  4. Normal contraction of LV J Am CollCardiolImg 2008;1:366 –76

  5. Assessment of LV function

  6. Clinically relevant indicators of global LV function EJECTION FRACTION. • Ratio of SV to EDV. [EDV-ESV/EDV] • Simplicity of its derivation • Ability to determine easily • Reproducibility using different imaging techniques • Extensive documentation of its clinical usefulness.

  7. Ejection fraction Drawbacks • Depends on preload and afterload, as well as HR and synchronicity of contraction. • 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

  8. 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

  9. 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

  10. 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]

  11. 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

  12. Regional Indices of Left Ventricular Function • WMS [wall motion score] • Center line chordal shortening • Radian change, regional area change • Strain rate imaging • Torsion imaging

  13. Centerline method

  14. Angiographic assessment

  15. 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

  16. Regional indices Angiographic wall motion score • 1= normal • 2= moderate hypokinesis • 3=severe hypokinesis • 4=akinesis • 5=aneurysm/dyskinesis • Normal score is 5

  17. Echocardiography

  18. Assesment by Echocardiography Ejection Fraction • 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

  19. Ejection fraction 2. D3 method 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 L D1 D2

  20. Ejection fraction 3. Modified Simpson’s biplane method [2D-Echo] 20 • Vol= p/4 S ai bi L i=1 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

  21. Ejection Fraction 4. Single plane Area- length Method • When only one view is available • Ventricle is considered symmetrical • Vol= 0.85 A2 L

  22. 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

  23. 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

  24. 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

  25. Regional function indices • WMS • Normal =1 • Hypo=2 • Akinetic=3 • Dyskinetic=4 • WMSI S WMS/N

  26. Deformation analysis • Newer methods of TDI & speckle tracking • Analysis of strain, strain rate or torsion • Strain- L-L0/L0 • Strain rate- velocity of change over time

  27. Deformation analysis Drawbacks • Strain not uniform from base to apex & in circumferential plane [anterior & lateral wall higher] • Angle dependency • Preload dependent • Heterogenicity within the same myocardium • Patient to patient variability • Inter & Intra observer variability APEX

  28. 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.

  29. 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 CollCardiol 2006; 48:2053– 69

  30. 3D Echocardiography Am J Cardiol 2005;95:809–813

  31. Magnetic resonance imaging

  32. MRI • Gold standard for assessing LV & RV function

  33. MRI

  34. 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 CardiolClin 25 (2007) 15–33

  35. 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

  36. Computed tomography

  37. 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

  38. ECG gated CT

  39. Computed Tomography

  40. Computed Tomography MRI [Gold Standard] > MDCT>2D-Echo & SPECT Radiology 2005; 234:381–390

  41. Computed Tomography • Disadvantages • Radiation risk • Contrast toxicity • Temporal resolution comparably limited • Used when echo window very poor & MRI contraindicated

  42. Nuclear imaging

  43. 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

  44. SPECT

  45. SPECT LV contraction Histogram

  46. SPECT Prognostic Value of Lung Sestamibi Uptake in Myocardial Perfusion Imaging of Patients With Known or Suspected Coronary Artery Disease J Am CollCardiol, 2005; 45:1676-1682

  47. SPECT

  48. Take Home message • 2D Echo- most common • MRI- precision, complex geometry • Nuclear imaging, CT- used when other indications present J Am CollCardiolImg 2008;1:652–62

  49. Thank you

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