Echocardiogram

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Setup

  • Ensure probe marker is on the right of the image to indicate that the echocardiogram is in ‘cardiac mode’ and not ‘standard mode’
    • The left ventricle should always be on the left of the screen in parasternal long-axis view
  • Can ask the patient to lay on the left lateral decubitus position

Approach

  1. Parasternal long axis
  2. Parasternal short axis
  3. Apical 4 chamber
  4. Sub-xiphoid

Focused Cardiac Echocardiography

  • If possible place the patient in the left lateral decubitus position before beginning

Apical Four Chamber View

  • Set field depth to 15-20 cm

  • Place the probe at:

    • The point of maximal impulse or
    • Anterior axillary line and move towards the nipple in a Z shape pattern

  • Probably easier to go from the para-sternal short axis to the apical four chamber:

    • Point the probe marker towards the left axilla
    • Slide down toward the apex and you should see the chamber size getting smaller and smaller
    • When you get to the apex, fan up towards the patient’s head

  • Keep the probe at 60 degrees relative to the chest wall with the orientation marker pointing towards the 3 o’clock position

  • Identify the structures of interest:

    • Lateral and septal mitral annulae
    • Apex
    • Endocardial and epicardial borders

  • In this view the LV should take up 2/3 and the RV should take up 1/3

  • Use this view to assess longitudinal shortening with a ruler or M-mode vector line
  • Then assess thickening of wall segments
  • Then assess change in left ventricular cavity area

Parasternal Long Axis

  • Set the field depth to 12-20 cm
  • Place the probe at the the left third or fourth intercostal space
  • Point the orientation marker toward the 10 o’clock position (right shoulder) with the probe perpendicular to the chest wall

  • Identify the areas of interest including:
    • Anterior mitral-valve leaflet
    • Endocardial and epicardial borders
    • Midline of the left ventricular cavity

  • Assess anterior mitral valve leaflet motion, wall thickening, area of cavity change and longitudinal shortening
  • One can quantify the EF in this view by taking the M-mode line across the mitral valve septum:
    • Freeze the frame and identify:
      • interventricular septum and mitral valve
      • The distance between the mitral valve and the interventricular septum can be used to observe for LV dysfunction <7 mm is normal and >10 mm represents dysfunction
    • This study is susceptible to aortic regurgitation and mitral stenosis which will falsely predict LV dysfunction
  • This view can be used to differentiate a pericardial effusion from a pleural effusion
    • A pericardial effusion will show fluid build up anterior to the descending aorta
    • A pleural effusion will show fluid build up posterior to the descending aorta
  • Pericardial tamponade
    • Requires diastolic collapse of the right ventricle with clinical symptoms (e.g. hypotension, tachycardia, chest pain)
      • Can identify that collapse of the RV occurs during diastole as during this point in time the mitral valve leaflets are open
  • RV strain

Parasternal Short Axis

  • First obtain the long axis view (above), then point the orientation marker toward the 2 o’clock position (left shoulder), fan towards the apex and base and decrease the field of depth to 10-14 cm

  • Identify the structures of interest:

    • Endocardial and epicardial borders

  • Assess wall thickening and change in area of cavity

  • Can go more superiorly (towards the base) to see the aortic valve in its classic mercedes-benz sign configuration

  • Can also assess for right ventricular strain

    • In RV strain will see: enlarged RV and septal bowing causing the LV to take the appearance of a ‘D’

Subxiphoid View

  • With patient’s knees bent place the probe in the subxiphoid region with the indicator to the left
  • Use an overhand grip on the probe to obtain a lower angle (probe is almost parallel to the skin)
  • Start on the patient’s right, identify the liver and sweep to the left using the liver as an acoustic window

Echocardiographic Measures of Left Ventricular Systolic Function

  • If all 4 measures (below) are normal, it is reasonable to grade the estimated left ventricular systolic function as normal (with LVEF > 55%)
  • If all 4 measures (below) are abnromal, it is reasonable to grade the estimated left ventricular systolic function as abnormal (with LVEF < 30%)

Longitudinal Shortening

  • Best evaluated int he apical 4 chamber view but should also be evaluated in the parasternal long axis view
  • Identify a segment between the base (lateral and septal mitral annulae used as reference) and the apex of the heart
  • Compare maximum length at end-diastole and end-systole using a ruler or M-mode vector lien
  • A difference of ≥1 cm indicates normal left ventricular systolic function

Anterior Mitral-Leaflet Motion

  • Can only be evaluated int he parasternal long-axis view
  • Imagine a line from the base to the apex of the heart along the midline of the left ventricular cavity
    • In early diastole, the mitral valve leaflets separate widely
    • When the anterior leaflet extends beyond the midline, it indicates normal left ventricular systolic function
    • When it does not, it suggests severely reduced left ventricular systolic function

Thickening of Wall Segments

  • Best assessed in the parasternal short axis view but should also be assessed in the parasternal long axis and apical four chamber views
  • Wall thickness is minimal at end-diastole; during systole contraction of the myocardium causes wall thickness to increase
  • Uniform wall thickening with an increase in wall thickness by at least ≥1/3 indicates normal left ventricular systolic function

Change in the Area of the Cavity

  • Best evaluated in the parasternal short axis view but should also be assessed in the parasternal long axis and apical four chamber views
  • Review the area enclosed by the endocardial border between end-diastole and end-systole
  • A decrease by ≥ 1/3 indicates normal left ventricular systolic function

Sources

Disclaimer: These notes are for educational purposes only and are not medical advice. I do not claim copyright for the content or images unless otherwise stated. For concerns or changes, create a new issue on GitHub.

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