II. Technique: Transducer

  1. Transducer orientation: 4 chamber apical view
    1. echo_apical_4ch.png
    2. Transducer placed at PMI or approximately xiphoid level (6th intercostal space) in mid-clavicular line or nipple line
      1. Identify heart apex with other views (e.g. PLAX)
    3. Transducer indicator pointed towards patient's left (3:00 position)
    4. Align energy toward right Shoulder along heart's long axis
    5. Hand holding transducer is pushed with knuckles into the bed to get best angle through heart
    6. Four chamber apical view will appear bullet shaped, oriented vertically
    7. Alternative method to identify apical position
      1. Start in PSAX View and slide the probe to the point of maximal impulse, directed cephalad
  2. Transducer orientation: 5 chamber apical view
    1. echo_apical_5ch.png
    2. From 4 chamber view, angle the transducer slightly anterior toward the chest wall (decreased angle to the chest)
  3. Transducer orientation: 2 chamber apical view
    1. echo_apical2ch.png
    2. Fron 5 chamber view, rotate the probe toward 1:00 position toward left Shoulder
  4. Transducer orientation: 3 chamber apical view
    1. Fron 2 chamber view, rotate the probe toward 11:00 position toward right Shoulder
  5. Images
    1. ultrasoundHeartApical.jpg
    2. ultrasoundProbePositionEchoApical.jpg
    3. ultrasoundBMP_cvApical.jpg

III. Technique: Landmarks

  1. Apical 4 Chamber View
    1. echo_apical_4ch.png
    2. Right ventricle
      1. Triangular appearance
      2. Does not extend to the apex (unless the heart is foreshortened due to an inadequate view)
    3. Left ventricle
      1. View should show apex
    4. Tricuspid valve
      1. Appears higher on the screen, closer to probe, more inferior in chest
    5. Mitral valve
      1. Trace regurgitation is common
    6. Right atrium, left atrium
    7. Pulmonary veins and descending aorta
  2. Apical 5 Chamber View
    1. Similar to 4 chamber, but aortic outflow, aortic valve and aortic root appear between right and left atrium
    2. Right ventricle, intraventricular septum and Left ventricle
    3. Tricuspid valve and Mitral valve
    4. Right atrium, aortic outflow, aortic valve, aortic root and left atrium
  3. Apical 2 Chamber View
    1. Apex
    2. Left ventricle
    3. Mitral Valve
    4. Left Atrium and left atrial appendage
  4. Apical 3 Chamber View
    1. Similar to standard PLAX View, but the orientation is rotated 90 degrees to vertical on screen
    2. Left Ventricle, Intraventricular Septum and Right Ventricular Outflow Tract
    3. Left Atrium, left ventricular outflow tract and aorta

IV. Interpretation: General

  1. Approach
    1. Pericardial Effusion (best view for Pericardiocentesis)
    2. Apical thrombus (decrease depth to see, apex is closest to probe in this location)
    3. Systolic Dysfunction
    4. Wall motion abnormalities
  2. Measurements: 2D
    1. Left Ventricular Function (Ejection Fraction) by biplane (simpson method of discs)
      1. echo_apical_LeftVentricleArea.png
      2. echo_apical2ch_LV_area.png
      3. Trace left ventricular volume (mid-mitral annulus to apex) at end-diastole and end-systole in 4 chamber view
      4. Trace left ventricular volume (mid-mitral annulus to apex) at end-diastole and end-systole in 2 chamber view
        1. Ventricular length should be similar between the 4 chamber and 2 chamber views
    2. Left Atrial Dimensions
      1. echo_apical_LeftAtriumArea.png
      2. echo_apical2ch_LA_area.png
      3. Measure at end-systole in both 4 chamber and 2 chamber views
      4. Normal <34 ml/m2
      5. Increased (left atrial enlargement) in Hypertension, Mitral Stenosis, Mitral Regurgitation, left Diastolic Dysfunction
  3. Measurements: Doppler
    1. Mitral Valve (4 chamber view)
      1. Color: Maximal jets, eccentric jets, multiple jets
      2. Pulse Wave Doppler: Mitral Valve E and A Waves (with cursor at mitral valve leaflets)
        1. echoApical4_pulseWave_Mitral.png
        2. Characteristic Biphasic M-Configuration
        3. Waves are upright (toward transducer)
      3. Continuous Wave Doppler: Mitral Regurgitation Jet velocities (trace wave)
        1. Normal mitral valve peak velocity 0.6 to 1.3 m/s
        2. Mitral Regurgitation will appear as negative wave (away from transducer) during systole
        3. Mitral Stenosis will show a flattened/notched appearance to the E and A waves during diastolic filling
      4. Mitral Valve Area by Pressure Half-Time (PHT) for native valves
        1. Optimize the Continuous Wave Doppler at mitral valve inflow
        2. Trace the mitral valve E Wave slope
        3. Machine will calculate the PHT, the time at which pressure has dropped 50%
        4. MVA (in cm2) = 220/PHT
        5. Normal MVA >= 2 cm2
          1. Severe Mitral Stenosis MVA <1 cm2 (>10 mmHg mean pressure gradient)
    2. Tricuspid Valve (4 chamber view)
      1. Similar to Mitral Valve pulse wave doppler appearance (biphasic M configuration)
      2. Similar to Mitral Valve Continuous Wave Doppler appearance
        1. Normal tricuspid valve peak velocity 0.3 to 0.7 m/s
        2. Tricuspid stenosis will show a flattened, downward sloping E to A during diastolic filling
        3. Tricuspid regurgitation will appear as negative wave (away from transducer) during systole
      3. Right Ventricular Systolic Pressure (RVSP) Measurement
        1. Even trace tricuspid regurgitation may be used to calculate right ventricular systolic pressure
        2. Measure tricuspid regurgitation peak velocity (TRPV or TRV, m/s) with Continuous Wave Doppler
          1. Typical tricuspid peak velocity = 2.5 m/s
          2. echoApical4_continuousWaveTricuspid_RVSP.png
        3. Estimate Right Atrial Pressure (RAP) based on inferior vena cava (IVC)
          1. RAP 3 mmHg: IVC <2.1 cm and collapses >50% on inspiration
          2. RAP 8 mmHg: IVC <2.1 cm (~3 mmHg) and collapses <50% on inspiration
          3. RAP 15 mmHg: IVC >2.1 cm (~3 mmHg) and collapses <50% on inspiration
        4. Right ventricular systolic pressure (RVSP in mmHg) = 4 * TRPV^2 + RAP
          1. Tricuspid regurgitation pressure = 4 * TRPV^2 (based on Bernoulli Equation)
          2. RVSP also reflects pulmonary artery pressure except in RV outflow obstruction
            1. Normal right ventricle (and PA) peak systolic pressure = 15 to 25 mmHg
          3. Not accurate in Ventricular Septal Defect (VSD)
            1. However, RVSP can be measured in PLAX View across the VSD
            2. Measure the pressure gradient peak velocity across the VSD (Vvsd)
            3. RVSP = BPsys - 4 * (Vvsd)^2
          4. Not accurate in Patent Ductus Arteriosus (PDA)
            1. However, RVSP or PASP can be measured in PSAX-Aorta
            2. Measure at the level of the PDA within the pulmonary artery
            3. PASP (or RVSP) = BPsys - 4 * (Vpda)^2
    3. LVOT and Aortic Valve (5 chamber view)
      1. Flow away from the transducer (negative deflection)
      2. Normal aortic peak velocity: 1.0 to 1.7 m/s
      3. Continuous Wave Doppler
        1. Aortic Regurgitation will result in positive deflections (toward transducer)
        2. Aortic Stenosis will result in negative deflections (away from transducer)
      4. Pulse Wave Doppler
        1. echoApical5_pulseWave_Aortic.png
        2. echoApical5_pulseWave_Aortic_VTI.png
      5. Precaution
        1. Aortic Stenosis jet and Mitral Regurgitation jet may be confused for one another

V. Interpretation: Stroke Volume (Velocity-Time Integral or VTI)

  1. Precautions
    1. Inaccurate in moderate to severe Aortic Regurgitation or dynamic LVOT obstruction
  2. View: Apical 5 Chamber View
    1. Start with 4 chamber apical view (see above)
    2. Angle the transducer slightly anterior toward the chest wall
  3. Measurement of Velocity-Time Integral (VTI) of the Left ventricular outflow tract (LVOT)
    1. Set Ultrasound machine to Pulse Wave doppler (PWD)
    2. Place cursor in Left ventricular outflow tract (LVOT)
      1. Place cursor as close to aortic valve without including it
    3. Capture Pulse Wave doppler (PWD) wave form and freeze the image
      1. PWD wave form will appear as a sharks fin
    4. Measure the area under the curve of the PWD wave form (LVOT VTI)
      1. Choose LVOT VTI from the Ultrasound calculation menu
      2. Manually trace the wave with the cursor
      3. Machine calculates the area under the curve (VTI in cm)
  4. Interpretation of Velocity-Time Integral (VTI in cm)
    1. Normal adult VTI = 18 to 22 cm (when Heart Rate 55 to 95 beats/min)
  5. References
    1. Blanco (2015) J Ultrasound Med 34(9): 1691-700 [PubMed]

VI. Interpretation: Fluid responsiveness based on Velocity-Time Integral (VTI in cm)

  1. Technique
    1. Obtain initial VTI measurement (as above)
    2. Perform Passive Leg Raise Maneuver (PLR Maneuver)
    3. Repeat VTI measurement (as above)
  2. Interpretation
    1. Increase in Velocity-Time Integral (VTI in cm) of 15% with passsive leg raise suggests fluid responsive
  3. References
    1. Blais (2009) Crit Care 13(6): R195 [PubMed]

VII. Resources

  1. Apical 4-Chamber View Video (SonoSite)
    1. http://www.youtube.com/watch?v=_eHZz-OCc_M
  2. Echocardiographer
    1. http://echocardiographer.org/

VIII. References

  1. Jordan (2019) Cardiac Ultrasound Protocol Manual, Gulfcoast Ultrasound, p 13-22
  2. Reynolds (2018) The Echocardiographer's Pocket Reference, Arizona Heart Association, p. 323-4
  3. Palma, Bourque and Jordan (2019) Introduction to Adult Echo Ultrasound Conference, GulfCoast Ultrasound, St. Petersburg
  4. Mateer and Jorgensen (2012) Introduction and Advanced Emergency Medicine Ultrasound Conference, GulfCoast Ultrasound, St. Pete's Beach
  5. Noble (2011) Emergency and Critical CareUltrasound, Cambridge University Press, New York, p. 61-88
  6. Orman, Dawson and Mallin in Majoewsky (2013) EM:Rap 13(1): 4-6
  7. Reardon (2011) Pocket Atlas Emergency Ultrasound, McGraw Hill, New York, p. 61-106
  8. Stowell, Kessler and Lotz (2017) Crit Dec Emerg Med 31(8): 13-22

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