LV Function and Haemodynamic Assessment Echocardiography

SYSTOLIC FUNCTION

Global Function

  • stroke volume: end-diastolic volume – end-systolic volume
  • cardiac output:

Q = SV X HR
= (Aortic Area x V x Tej) x HR

Q = cardiac output
Aortic area = cross sectional area
V = velocity for each beat
Tej = time period during ejection
HR = heart rate

  • ejection fraction: take two orthogonal views (apical four chamber and apical two chamber) ⇒ trace around endocardial border at the end of diastole and systole

EF = (EDV-ESV/EDV) x 100
(normal = 50-85%)

  • fractional shortening: percentage change in LV internal dimensions between systole and diastole (normal 30-45%)
  • preload: end-diastolic volume (if low think -> hypovolaemia, low SVR, severe AR or MR, VSD)
  • afterload: end-systolic wall stress (rarely used in clinical practice)
  • LV wall thickness: > 1.5cm = LVH, < 0.6cm = LV thinning

Regional Function

LV function echo 1

  • 16 segments
  • contractility: grades
    1 = normal or hyperkinetic
    2 = hypokinetic
    3 = akinetic
    4 = dyskinetic (paradoxical systolic motion)
    5 = aneurysmal

DIASTOLIC FUNCTION

  • relaxation requires energy (ATP)
  • phases of relaxation = isovolumetric relaxation, early filling, diastasis (when LA passively fills LV and then stops), atrial contraction
  • diastolic dysfunction = disorder of LV filling where LV is unable to fill to a normal LVEDV without an increase in end-diastolic pressure.
  • m-mode ‘slow relaxation’ in motion of the anterior mitral valve leaflet.

LV function echo 2

  • normal = E > A
  • abnormal = A > E
  • pseudonormal = E > A (LA dilated to compensated for lack of LV relaxation)
  • restrictive = E >>> A
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