Previous Topic

Next Topic

Book Contents

Book Index

17-Segment Model (AHA)

Left Ventricle Segmentation Procedure

The muscle and cavity of the left ventricle can be divided into a variable number of segments. Based on autopsy data the AHA recommends a division into 17 segments for the regional analysis of left ventricular function or myocardial perfusion:

PCARD 17-Segment Model Anatomical

Polar Plots

If functional values have been obtained in the 17 cardiac segments by some quantification method, they can be arranged as a polar plot with the

Such an arrangement makes it easy to compare the outcome in different conditions (eg. rest/stress) or between patients. The arrangement together with numbers identifying the cardiac segments is illustrated below.

PCARD 17-segment Model Polar Plot

 

Basal Segments

 

Mid-cavity Segments

 

Apical Segments

1.

basal anterior

7.

mid anterior

13.

apical anterior

2.

basal anteroseptal

8.

mid anteroseptal

14.

apical septal

3.

basal inferoseptal

9.

mid inferoseptal

15.

apical inferior

4.

basal inferior

10.

mid inferior

16.

apical lateral

5.

basal inferolateral

11.

mid inferolateral

17.

apex

6.

basal anterolateral

12.

mid anterolateral

 

 

The relative contribution of the basal, mid-cavity, and apical segments are 35% (6/17), 35% (6/17), and 30% (5/17), respectively.

Coronary Artery Territories

The AHA guidelines emphasize that there is a "tremendous variability in the coronary artery blood supply to myocardial segments". The greatest variability occurs at the apical cap, which can be supplied by any of the three arteries. With the recognition of the anatomic variability the individual segments may be assigned to specific coronary artery territories as follows.

Coronary Artery:

Segments

Left Anterior Descending (LAD)

1, 2, 7, 8, 13, 14, 17

Right Coronary Artery (RCA)

3, 4, 9, 10, 15

Left Circumflex (LCX)

5, 6, 11, 12, 16