LV 17 Segment Model

 
Editor's Note
 
The 17 segment model is new accepted and supercedes the 16 segement model. The 17 segment model is more consistent with other imaging modalities (MRI, CT, etc). The new segment is the apical segment that is not in the 16 segment model. Also, the posterior wall has been renamed the inferolateral wall, the septal wall has been renamed the infroseptal wall, and the septal wall has been renamed the inferoseptal wall.
 
Introduction
 
The 17 segment model adds an apical segment to the left ventricle.  In absence of a 17th segment, ischemia of the apical portion of the left ventricle was disproportionately represented in the wall motion index score.  With a 17th segment, the apical or distal segments of the left ventricular walls can also be represented in the wall motion index score if they are involved, and not represented if only the apical segment is involved.  Also, the 17th segment is also consistent with other imaging techniques of the left ventricle, where an apical segment is defined.
Walls of the Left Ventricle
The right and the left ventricles are divided into six walls.  The left ventricular walls are anterior, anteroseptal, inferoseptal, inferior, inferolateral and anterolateral.  The right ventricle has a free wall and a septal wall (left ventricular septal wall). 
 
Left Ventricular Walls Right Ventricular Walls
  • Anterior
  • Anteroseptal
  • Inferoseptal
  • Inferior
  • Inferolateral
  • Lateral
  • Free Wall
  • Septal Wall
 
The Walls of the Heart & Apical Segment
Anterior Inferior Inferolateral
Anteroseptal Inferoseptal
Anterolateral Apical Segment
 
Segments of the Heart (Apical View)
 
The segments close the the base of the heart, the basal segments are named for the wall to which they belong.  There are six segments, numbered 1 thru 6, starting with the basal anteroseptal segment(1) and, going in a counter-clockwise direction, passing thru the basal anterior segment(2), basal anterolateral segment(3), basal inferolateral segment(4), basal inferior segment(5), and ending with the basal inferoseptal segment(6).  All basal segments will include views of the base of the heart and the mitral valve.

The mid segments also number six segments.  Again, starting with the mid anteroseptal segment(7) and traveling in a counter clockwise direction thru the mid anterior segment(8), mid anterolateral segment(9), mid inferolateral segment(10), mid inferior segment(11), and ending in a mid inferoseptal segment(12).  All views of mid segments will include or be at the level of the papillary muscles.

The apical segments only number four segments.  The inferolateral wall and anteroseptal wall do not have apical segments.  The segments rotate thru the apical anterior segment(13), apical lateral segment(14), apical inferior segment(15), and end with the apical septal segment(16). The 17th segment is called the apical (17) segment.  All apical segments will not include and be distal to the level of the papillary muscles.
Basal Mid Apical Segments
Segments
Segments of the Heart (Midesophageal Views)
 
From the midesophageal acoustic window, all 16 segments can be seen in the various views.  The 4 chamber view has the basal, mid and apical segments of the septum and the lateral wall.  The 2 chamber view has the basal, mid, and apical segments of the inferior and anterior wall.  The long axis of the left ventricle has the basal and mid segments of the anteroseptal and posterior wall.  All views, if not foreshortened, contain the apical (17) segment.
1 2 3 4 5 6
7 8 9 10 11 12
  13 14 15 16 17
Major Segments of the Heart
Segments of the Heart (All Views)
 
Below, the segments are named and numbered in standard midesophageal and transgastric views.  Also, if the left ventricle was view from it's apex, the segmentation number and naming system becomes evident.  Move your mouse over a segment to reveal its name.
 
  • 1.   Basal Anteroseptal
  • 2.   Basal Anterior
  • 3.   Basal Anterolateral
  • 4.   Basal Inferolateral
  • 5.   Basal Inferior
  • 6.   Basal Inferoseptal
  • 7.   Mid Anteroseptal
  • 8.   Mid Anterior
  • 9.   Mid Anterolateral
  • 10. Mid Inferolateral
  • 11. Mid Inferior
  • 12. Mid Inferoseptal
  • 13. Apical Anterior
  • 14. Apical Lateral
  • 15. Apical Inferior
  • 16. Apical Septal
  • 17. Apical
Apical View Transgastric LVLAX View
ME 4CV ME 2CV ME AVLAX
TG Basal LVSAX TG Mid LVSAX TG Apical LVSAX