Apical Anatomy (2)

SAIT School of Health and Public Safety DMST 253 Echocardiography 1: Apical Anatomy

Apical 4 Chamber (A4C)

• A4C is an essential echocardiographic view that provides a comprehensive understanding of the heart's anatomy from the apex perspective.

• Visualized structures include:
    - 1) Left Ventricle (LV)
    - 2) Interventricular Septum (IVS) - specifically the LV inferoseptal wall
    - 3) LV anterolateral wall
    - 4) Mitral Valve (MV) anterior leaflet
    - 5) MV posterior leaflet
    - 6) Left Atrium (LA)
    - 7) Left Atrial Appendage (LAA) which may or may not be visible
    - 8) Interatrial Septum (IAS)
    - 9) Right Upper Pulmonary Vein (RUPV) which may or may not be visible
    - 10) Ductus Arteriosus (DA)
    - 11) Right Ventricle (RV)
    - 12) RV Free Wall
    - 13) Tricuspid Valve (TV)
    - 14) Right Atrium (RA)

Additional Visible Structures in A4C

• In addition to the primary structures, the following may also be visualized in A4C:
    - RV, Moderator band, Specific RV features.
    - TV leaflets:
      - Anterior leaflet
      - Septal leaflet

• Right Atrium (RA): Includes the following features:
    - 1) Eustachian Valve - A membranous flap
    - 2) Chiari network - A delicate membranous structure
    - 3) Crista Terminalis - A crescent-shaped ridge
    - 4) Coronary sinus - Involved in coronary venous return

A4C Viewing Technique

• To achieve the A4C view:
    1) Start with the probe at the apex.
    2) Angle the probe anteriorly to transition to the Apical 5 Chamber (A5C).
    3) Return to center for A4C view.
    4) Angle posteriorly to obtain an off-axis view of the coronary sinus.

Apical 5 Chamber (A5C)

• The A5C is obtained from the same position as A4C, but the transducer is angled anteriorly.

• Visualized structures include:
    - 1) Left Ventricle (LV)
    - 2) Interventricular Septum (IVS)
    - 3) LV anterolateral wall
    - 4) Mitral Valve (MV) +/- visibility
    - 5) Left Atrium (LA) +/- visibility
    - 6) Left Ventricular Outflow Tract (LVOT)
    - 7) Aortic Valve (AV)
    - 8) Ascending Aorta
    - 9) Right Ventricle (RV)
    - 10) RV Free Wall

A5C Technical Specifications

• Two different A5C configurations noted:
    - Configuration 1:
      - Frequency: 64-2
      - Hz: 7
      - Depth: 7 cm
      - Quality: 72%
      - Heart Rate: 75 bpm
    - Configuration 2:
      - Frequency: S4-2
      - Hz: 47
      - Depth: 17 cm
      - Quality: 70%
      - Heart Rate: 71 bpm

Apical 2 Chamber (A2C)

• The A2C view displays the following structures:
    - 1) Left Ventricle (LV)
    - 2) LV inferior wall
    - 3) LV anterior wall
    - 4) Anterior MV leaflet
    - 5) Posterior MV leaflet
    - 6) Papillary muscle (PM)
    - 7) Left Atrium (LA)
    - 8) Left Atrial Appendage (LAA) +/- visibility
    - 9) Coronary sinus +/- visibility
    - 10) Length of the descending aorta which is visualized with lateral or posterior angulation

A2C Technical Specifications

• A2C Example Configuration:
    - Frequency: S4-2
    - Hz: 42
    - Depth: 20 cm
    - Quality: 74%
    - Heart Rate: 69 bpm

Apical 3 Chamber (A3C)

• The A3C view visualizes the following anatomical structures:
    - 1) Left Ventricle (LV)
    - 2) LV inferolateral wall
    - 3) LV anteroseptal wall (IVS)
    - 4) Anterior MV leaflet
    - 5) Posterior MV leaflet
    - 6) Left Atrium (LA)
    - 7) Aortic Valve (AV) - Right Coronary Cusp (RCC)
    - 8) Aortic Valve (AV) - Non-coronary Cusp (NCC)
    - 9) Ascending Aorta
    - 10) Right Ventricle (RV)

MV Leaflets Anatomy by View

• Comprehension of MV leaflets requires understanding their anatomy through various views:
    - A4C, A2C, and A3C
    - Reference: Chazal, Sami, The Book of Echo. 2019. Fig 10-29/30/31

Apical LV Wall Segments – Overview

• Breakdown of LV wall segments at different anatomical levels:
    - 1) Anteroseptal
    - 2) Inferolateral
    - 3) Anterior
    - 4) Inferior
    - 5) Anterolateral
    - 6) Inferoseptal
    - Apex Level: Pap muscle denotes mid-level
  
  

LV Perfusion Territories

• Distribution of blood supply through coronary arteries:
    - Anterior heart:
      - Anterior
      - Anteroseptal
      - +/- Anterolateral
      - Apex
      - Septum
    - Right heart:
      - Inferior walls:
      - Inferior
      - Inferoseptal
      - Inferolateral
    - Lateral heart:
      - May include segments perfused by either Anterolateral or Inferolateral branches of left anterior descending (LAD), right coronary artery (RCA), or circumflex artery (CX)

Comprehension Questions

• Key questions for review and understanding:
    1. Can I identify and name the LV walls in each of the apical views?
    2. Can I identify the two MV leaflets in each apical view?
    3. In which view is the coronary sinus seen? What is the coronary sinus and which chamber does it empty into?
    4. Which approximate areas of the heart are supplied by the LAD, CX, and RCA?

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