Question 8 : ECHO 2 days post AMI

Question 8

A 50 year old man presents 2 days post AMI with hypotension. You are about to scan him looking for a cause. Outline possible ultrasound findings

1. Global LV regional abnormality

  • Reduced fractional shortening of LV . Not accurate in regional wall abnormalities/aneurysms/ LBBB
  • Simpson’s method 4 and 2 chamber views assesses cardiac ouput
  • Systolic index of contractility : dP/dt  if MR present and normal LA pressures
  • Eyeballing LV for assessment of function
  • MAPSE using M mode
  • Tissue Doppler at level of lateral mitral valve annulus . Peak velocity of > 5.4 cm/sec is normal

2. Aneurysm

  • Aneurysm formation – mainly post LAD infarcts – apical aneurysm best appreciated in 2 but also in 4 cV and atypical views.
  • Dilation and akinesis of aneurysmal area
  • Slow flow phenomenon in aneurysmal area

3. Myocardial rupture

  • Pericardial effusion (blood) May be echoic
  • Catastophic event

4. Pericardial effusion. Post MI pericarditis

5. Significant regional wall abnormality

6. Right heart failure

7. Thrombus

  • 2D ECHO to look for thrombus. Need to put the focus in the area of interest. Early on thrombi are completely anechoic and may not be seen
  • Put colour Doppler to check that thrombus does not perfuse
  • Visible in > 1 plane
  • Measure size to monitor treatment effect

8. Evidence of Regional wall abnormality:

  • Big anterior infarct – best seen in 2cV, 3CV, PSAX view and 4chamber (apex)
  • Big RCA – Inferior wall best seen in 4 chamber and 2 chamber views

9. Evidence of poor RV function

  • Size of RV – best appreciated in 4 chamber view Mid RV diameter > 4 cm is abnormal. Compare with LV by eyeballing but ensure view is not foreshortened
  • Poor longitudinal contraction of RV : TAPSE (normal 1.5 -2.0 TAPSE < 16 mm is abnormal)
  • Movement of IVS towards LV post infarct indicating high volume (in diastole) or high pressure (in systole) overload

10. Ventricular Septal rupture

  • Can see a disrupted interventricular septum (usually distal anterior or basal inferior)
  • Colour Doppler shows flow from LV to RV I systole
  • CW Doppler velocity depends on the size of the rupture and the pressure gradient between the right and left ventricles

11. Mitral regurgitation due to flail MV leaflet

  • May have a lack of distinct mitral regurgitation jet due to a large regurgitant orifice and low flow velocity mitral regurgitation – need TEE
  • Triangular shape of mitral regurgitation because of low systolic blood pressure in shock and pressure equilibrium between the left ventricle and the left atrium

Assess extension of AMI by looking at previous ECHOs

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