Apical views

How to acquire Apical views?

The patient is still on his left side, but rotated more onto their back for better access to the left side of the chest.‍‍

The apical window is usually found in the fifth intercostal space between the mid-clavicular and mid-axillary line. Position of the apex depends on the patient’s constitution.

The heart is viewed along its long axis, from the apex to the atria. 2/3 of the view should consist of the ventricles and 1/3 atria.

Left ventricle (LV) should have an ellipsoid shape at the apex, if the apex is rounded the ventricle is probably foreshortened !

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From apex we visualize:

1) Apical four chamber view (A4C)

2) Apical five chamber view (A5C)

3) Apical 2 chamber view (A2C)

4) Apical 3 chamber view (A3C)

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1) Apical Four Chamber view (A4C)

• Place the transducer at the palpated apical impulse, usually in the 5th intercostal space
• Marker at 3 o’clock
• Ensure that all 4 chambers are seen in the centre of the image – left-sided structures on the right, right-sided on the left and the apex at the top and center of the sector.
• The interventricular septum (IVS) should appear vertical and parallel to the US beam – move the transducer medially or laterally to achieve this
• Both mitral valve (MV) leaflets and two of the tricuspid valve (TV) leaflets should be visible
• If the ventricles appear spherical, move the transducer one interspace lower
• To better view the atria – tilt the probe anteriorly
• Aortic valve should not be seen in A4C – if it is, tilt the probe posteriorly

Image 1 A4C position of the transducer - marker at 3 o’clock (not visible on this image)

Image 2 A4C anatomical tructures

What should we assess in the A4C view ?

• LV: dimensions, longitudinal and radial function, aneurysm, thrombus
• Mitral Valve assessment – morphology, MR/MS
• Diastolic function of LV
• RV: size and function, pacing wires
• Tricuspid Valve
• RA: size
• LA: size and volume
• Pericardial effusion
• Ventricular and atrial septal defect
• Intra-cardiac mass

a) LV wall motion, size, volume and systolic function assessment

• This view is useful for overall LV examination.
• The following method for systolic function assessment are described in detail in Systolic dysfunction chapter:
• Assess the wall motion using the eyeballing method according to each LV wall segment.
• Global longitudinal strain (GLS) is used to evaluate regional myocardial function and therefore directly reveals the contractile function of the heart. It can reveal LV dysfunction way before EF drops. The apical long axis (A3C), four chamber A4C and two chamber A2C standard views are used.

Video 1 Normal A4C view

LV wall motion visual assessment (Image 3)

• Anterior septum and posterolateral segments of LV are seen in this view
• Using the eyeballing method observe the wall thickening and endocardial motion of the LV wall

Fen-Chiung Lin, I-Chang Hsieh, Cheng-Hung Lee, Ming-Sien Wen. Introduction of Tissue Doppler Imaging Echocardiography—Based on Pulsed-wave Mode,Journal of Medical Ultrasound, Volume 16, Issue 3, 2008, Pages 202-209.

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Ejection fraction (LVEF)

An estimate of LVEF should be included in all echo reports. Ejection fraction is derived from the End Diastolic Volume and End Systolic Volume estimates. 

It is the relation between the amount of blood expelled during each cardiac cycle relative to the size of the ventricle. Currently the Biplane Method of Disks (modified Simpson’s rule), derived from the 2D images measured in A4C and A2C views is recommended to assess the LV EF.

Formula: EF = (EDV-ESV)/EDV x 100 (EF= Ejection fraction, EDV= End-Diastolic Volume, ESV= End-Systolic Volume)

‍LV volume assessment

• LV volumes should be obtained using 2D imaging from A4C and A2C, preferably focused on the LV. 
• Zoom on the LV area and make sure the LV is not foreshortened.
• Trace the endocardial-blood interface (compacted myocardium and the cavity) at end-diastole and end-systole on images with clear endocardial border
• Take both tracings in A4C and then again in A2C view.
• Papillary muscles and trabeculations are excluded from the cavity tracings and considered part of the chamber.
• LV length is defined as the distance between the midpoint of the mitral valve level line and the most distal point of the LV apex.
  

‍Image 4 LV normal ranges of size, volume and function‍

Adapted from: Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015 Jan;28(1):1-39.e14.

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b) Mitral Valve assessment

A4C shows an oblique plane of the anterior leaflet with A3, A2 and P1 visible. This view gives us a perspective of the AV valves, with the MV annulus in a superior position to the tricuspid annulus (further from the apex) and inter-annular distance of 5-11 mm.

Presence and severity of Mitral Regurgitation is assessed using the procedure described in the MR chapter.

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‍c) Diastolic function assessment

Diastolic function describes the filling of the heart during diastole. Diastolic dysfunction is then understood as impaired left ventricular relaxation with increased stiffness of the LV and elevated filling pressures.

All following measurement methods are described in detail in the Diastolic Dysfunction chapter.

Various variables are measured:

• Mitral inflow - Emax, Amax, E/A ratio
• e´
• E/e´ ratio
• LA maximum volume index
• peak TR velocity

I) Mitral inflow - Emax, Amax, E/A ratio & DT

• Using the PWD, place sample volume at the level of the MV leaflet tips in the diastole.
• Use of CFD can help to align the centre of trans-mitral flow.
• Measure at end expiration.

Emax: peak velocity in early diastole.

Amax: peak velocity in late diastole (after P wave) = atrial contraction

E/A ratio: helps characterize the overall mitral flow velocity pattern and define diastolic function.

DT: shows how rapidly flow velocity declines in early diastole. Flow deceleration time from peak E wave to end of E wave signal. (E-wave deceleration time = DT)

Image 5 Normal mitral inflow - Pulse doppler used.

‍Image 6 Mitral inflow, impaired left ventricular relaxation - ulse doppler is used

II) Septal and lateral mitral annular peak early diastolic velocity (e′)

III) e′, E/e′,S′

• Use the PW tissue Doppler and place the sample volume at or within 1cm of the insertion of the mitral valve leaflets at the septal side and then on the lateral wall. 
• Both measurements are averaged.
• Measure at end expiration. 
• Optimise scale and sweep speed (100 mm/s).

IV) E/e‘: The ratio of the peak velocity of mitral inflow during early diastole (E) over the average of septal and lateral mitral annular early diastolic peak velocities (e′). The mitral E/e′ index correlates with LV stiffness and fibrosis.

V) S′: Peak systolic velocity.

Image 7 Normal septal mitral annular peak early diastolic velocity - Pulse tissue doppler used.

Image 8 Normal lateral mitral annular peak early diastolic velocity - Pulse tissue doppler used.

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‍d) Right ventricle assessment

• RV is visually assessed in an RV focused view.
• From the A4C view slide and/or angulate the tail of the transducer along the horizontal plane to place the RV in the centre of the image so that the LVOT is not seen.
• Next, rotate the transducer to obtain the maximum diameter.

RV diameter 

• All RV dimensions should be measured at end-diastole.
• RVD1: Basal RV diameter. Measured at the maximal transverse diameter in the basal one third of the RV.
• RVD2: Mid RV diameter measured at the level of the LV papillary muscles.
• RVD3: RV length, from the plane of the tricuspid annulus to the RV apex.

Image 9 Normal RV chamber size values

Adapted from: Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of, Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2016 Apr;17(4):412. doi: 10.1093/ehjci/jew041. Epub 2016 Mar 15. Erratum for: Eur Heart J Cardiovasc Imaging. 2015 Mar;16(3):233-70. PMID: 26983884.

‍Image 10 Normal diameter of RV (RVD1)

Image 11 Mildly dilated RV (abnormal RVD2 and RVD3)

‍Systolic function of RV assessment

• RV wall motion and thickness
• RV length and area
• Interventricular Shape and Motion
• Tissue Doppler imaging for right ventricular function -  Systolic excursion velocity (S’)
• TAPSE
• Fractional area change (FAC)
• RV strain analysis
• More in detail in Systolic Dysfunction chapter.

‍I) Tissue Doppler imaging for right ventricular function - S’ (Doppler myocardial velocity in systole)

- Longitudinal function of the right ventricle can be assessed with tissue Doppler.

- This is performed by placing the sample volume at the base of the free right ventricular wall.

- The maximal velocity of "S" represents longitudinal right ventricular function.

- Abnormal Threshold < 9.5 cm/s

Image 12 Normal systolic excursion velocity of RV - tissue doppler (0.11 m/s = 11 cm/s)

II) TAPSE – Tricuspid Annular Plane Systolic Excursion

• Visualize the heart in A4C view and align the M-mode cursor along the direction of the lateral tricuspid or mitral annulus, measuring the total excursion of mitral/tricuspid valve during systole and diastole.
• TAPSE > 17 mm is considered normal.

Image 13 Normal TAPSE - M-mode

III) Fractional area change (FAC)

Direct quantification can be performed by calculating fractional area change, which is done by tracing the end-diastolic and end-systolic cavity, and calculating the percentage change in area.

(Enddiastolic Area-Endsystolic Area/Enddiastolic Area) x 100

See more about normal and pathological values of FAC in Section Left ventricular function assessment.

Image 14 and 15 Fractional area change measurement in systole and diastole

e) Tricuspid regurgitation peak velocity

• Use the CW Doppler and place the cursor between tricuspid leaflet tips.
• Measure in systole (ECG: R wave - the end of T wave)
• Colour Doppler helps with blood flow identification.

Image 16 Abnormal (high) peak velocity on tricuspid regurgitation - sign of elevated pressure in pulmonary artery - Continual doppler used.

‍Tricuspid valve assessment

• Morphology of the TV is assessed in this view with TR presence and severity evaluation

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f) Right atrial area

• Obtain the RV focussed view from A4C
• Measure at the end of ventricular systole one frame prior to TV opening
• Trace the inner edge of the endocardium of the RA along the interatrial septum, superior and lateral walls of RA.
• Trace the RA inner border excluding the area under the TV annulus and the confluences of the RA appendage.
• right atrial area >18 cm2 is considered to be abnormal

Image 17 Right and left atrial area measured from A4C

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g) LA area and volume measurements

• Measure at end-systole before the MV opens, when the LA is at its greatest dimension
• Optimize the A4C and A2C views to demonstrate the maximal LA length and volume.
• Similarly to the LV volume, trace the endocardial border of the LA with a straight line connecting the leaflet insertion points into the MV annulus.
• Exclude LA appendage and pulmonary veins from the tracings.¨
• The length of the LA should be measured in both views – from the centre of the mitral annulus to the inner edge of the furthest point of the LA wall.
• The difference between A4C and A2C measurements should not exceed 5 mm, if that happens review and optimize the views.
• The ultrasound machine automatically calculates the LA area and volume.

Image 18 Left atrial area measured from A4C

Image 19 Left atrial normal and pathological reference values

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2) Apical Five Chamber view

To obtain the five-chamber view you need to start with a four-chamber view and "tilt" it ventrally.

To obtain a nice five-chamber view move the transducer further laterally so that the septum is in oblique position.

On the five-chamber view you can appreciate the LVOT and the aortic valve, which is positioned closer to the chest.

‍Video 2 A5C view with documented aortic valve

Video 3 A5C view with Colour Doppler

Image 20 Measurement of LVOT VTI in A5C view = cursor above aortic valve in LVOT

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3) Apical Two Chamber view (A2C)

• A2C is a orthogonal plane to the A4C view
• From A4C, rotate the probe 60-90° counterclockwise with the marker pointing towards the left axilla at 1 o’clock
• The left atrium, mitral valve and left ventricle are visualized 
• LA appendage along the right side and left upper pulmonary vein may be visible 
• Right heart, AV and LVOT should not be visible – adjust the rotation

Image 21 A2C position of the transducer - marker pointing towards the left axilla at 1 o’clock

Video 4 Normal A2C view

Image 22 A2C anatomy

‍Image 23 Left atrial area measured from A2C

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3) Apical Three Chamber view (A3C)

• Also known as the Apical long axis view, but this time the apex is seen
• From the A2C view, rotate the probe further 60° counterclockwise, marker pointing towards the right axilla at 11 o’clock

• This view shows different planes of the LV, LVOT, LA, aortic and mitral valve
• LVOT is more parallel in this view and is ideal to study flow in the LVOT (Aortic regurgitation)

Image 24 A3C position of the transducer - marker pointing towards the right axilla at 11 o’clock

‍Video 5 Normal A3C view

Image 25 A3C anatomy

‍Video 6 Colour Doppler focused on Aortic valve in A3C - no Aortic regurgitation present

‍Aortic valve assessment

• If the A5C view is suboptimal for AV assessment, A3C view may be used.
• AV morphology, calcification, thickening and leaflet motion is viewed
• Use the CW Doppler to measure – AV max gradient, AV mean velocity, AV mean gradient, AV VTI (Velocity Time Integral)
• Apply the PW Doppler on LVOT to measure Vmax & VTI in there and to calculate stroke volume (SV) and cardiac output (CO)

Image 26 LVOT VTI measurement from A3C (VTI = 24)

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‍References

1. Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, Flachskampf FA, Foster E, Goldstein SA, Kuznetsova T, Lancellotti P, Muraru D, Picard MH, Rietzschel ER, Rudski L, Spencer KT, Tsang W, Voigt JU. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015 Jan;28(1):1-39.e14. doi: 10.1016/j.echo.2014.10.003. PMID: 25559473.
2. Mitchell C, Rahko PS, Blauwet LA, Canaday B, Finstuen JA, Foster MC, Horton K, Ogunyankin KO, Palma RA, Velazquez EJ. Guidelines for Performing a Comprehensive Transthoracic Echocardiographic Examination in Adults: Recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2019 Jan;32(1):1-64. doi: 10.1016/j.echo.2018.06.004. Epub 2018 Oct 1. PMID: 30282592.
3. Ayan R Patel, MD (2021). Transthoracic echocardiography: Normal cardiac anatomy and tomographic views. In I. Susan B Yeon, MD, JD, FACC (Ed.), UpToDate. Retrieved August 4, 2021 from https://www-uptodate-com.ezproxy.is.cuni.cz/contents/transthoracic-echocardiography-normal-cardiac-anatomy-and-tomographic-views?search=echocardiography%20chambers&source=search_result&selectedTitle=5~150&usage_type=default&display_rank=5
4. CAMM, A. J., LÜSCHER, T. F., & SERRUYS, P. W. (2009). The ESC textbook of cardiovascular medicine. Oxford, Oxford University Press
5. Otto, C. M. (2018). Textbook of clinical echocardiography. 
6. http://pie.med.utoronto.ca/tte/TTE_content/standardviews.html#introduction
7. ASE Workflow & Lab Management Taskforce: David A. Orsinelli, MD, FASE (Chair), Alicia Armour, BS, MA, RDCS, FASE, Jeanne De Cara, MD, FASE, Brian Fey, RDCS, ACS, FASE, Peter Frommelt, MD, FASE, Juan Lopez-Mattei, MD, FASE, Jane Marshall, BS, RDCS, FASE, Athena Poppas, MD, FASE, Vandana Sachdev, MD, FASE, Liza Sanchez, RCS, FASE, and Timothy Woods, MD, FASE, Columbus, Ohio; Durham, North Carolina; Chicago, Illinois; Milwaukee, Wisconsin; Houston, Texas; Boston, Massachusetts; Providence, Rhode Island; Bethesda, Maryland; Memphis, Tennessee. 

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