Regional Systolic Function
Evaluation of regional systolic function is particularly useful in order to detect coronary artery diseases at rest or during stress (exercise or pharmacological) although other cardiac diseases might be associated with abnormal regional systolic function. The most common assessment of regional systolic function is usually based on a qualitative or semi-quantitative visual evaluation of the myocardial thickening. However, techniques based on Doppler (tissue Doppler imaging) or more recently based on the tracking of the speckles (speckle tracking imaging) allow a quantitative evaluation of regional systolic function.
Left ventricular segmentation
16 and 17 segment modelIn order to assess regional systolic function, the left ventricle is artificially divided into different segments. The currently recommended segmentation is a 17-segment model as described in the figure. 
Coronary flow distribution and left ventricular segmentation
Anatomic variability regarding coronary artery blood supply is important. However, based on the most common anatomy, current guidelines assigned each segment to one coronary artery as follows:
- Segments 1, 2, 7, 8, 13, 14, and 17 to the left anterior descending coronary artery;
- Segments 3, 4, 9, 10, and 15 are assigned to the right coronary artery;
- Segments 5, 6, 11, 12, and 16 generally are assigned to the left circumflex artery.
- However, the following variations are common:
- The segment 9 (mid inferoseptal): right coronary artery or left anterior descending artery;
- The segments 5 (basal inferolateral) and 11 (mid inferolateral): right coronary artery or circumflex;
- The segments 6 (basal anterolateral), 12 (mid anterolateral),and 16 (apical anterolateral) : left anterior descending artery or circumflex.
Right ventricular segmentation
The right ventricle is divided into 3 walls: anterior, lateral (also called right ventricular free wall) and posterior wall and share the septal wall with the left ventricle. Each wall is divided into a basal, mid and apical segment.  The right coronary artery is the primary coronary supply to the right ventricle via acute marginal branches.
Visual Wall motion analysis
Visualization of left ventricular walls
The classical echocardiographic views allow assessment of the 6 walls with the 17 left ventricular segments as follows:
- The parasternal long axis view and 3-apical chamber views assessing the anteroseptal and posterolateral walls;
- The short axis views assessing the 6 walls at the basal, mid and apical levels;
- The apical 4-chamber view assessing the inferoseptal and anterolateral walls;
- The apical 2-chamber view assessing the inferior and anterior walls.
Endocardial motion and myocardial thickening
Echocardiography can overestimate the amount of ischemic or infarcted myocardium, as wall motion of adjacent regions may be affected by tethering, disturbance of regional loading conditions and stunning. Therefore, wall thickening appears more precise than motion in order to evaluate the extent of regional systolic abnormalities. Regional wall motion abnormalities may occur in the absence of coronary artery disease.
- Hyperkinesis= increase in thickening. This phenomenon may be observed for example in the remote segments of a myocardial infarction.
- Normokinesis= normal thickening of the myocardial segment
- Hypokinesis= decrease in thickening
- Akinesis= absence of thickening
- Dyskinesis= paradoxical systolic motion
- Aneurysm= diastolic deformation
Wall motion score index
Wall motion score index is a semi-quantitative analysis of regional systolic function. Each segment is analyzed individually and scored on the basis of its motion and systolic thickening. Ideally, the function of each segment should be confirmed in multiple views. This score is a 5-level score defines as follows:
- score 1= normokinesis or hyperkinesis
- score 2= hypokinesis
- score 3= akinesis
- score 4= dyskinesis
- score 5= aneurysm
- Wall motion score index is derived as a sum of all scores divided by the number of segments visualized.
Regional systolic function abnormalities in coronary artery diseases
Although regional wall motion abnormalities at rest may not be seen until the luminal diameter stenosis exceeds 85%, analysis of regional systolic function during stress (pharmacological or exercise) is useful to unmask significant coronary lesion.  (See Basic Principles of stress echocardiography)
Opacification of the left ventricle
Analysis of regional systolic function requires good endocardial border definition. In patients with suboptimal acoustic windows, contrast administration improves image quality through improvement of endocardial border definition and enhances detection of regional systolic function abnormalities.  (See Contrast Agents)
Quantitative techniques: Tissue Doppler and speckle tracking imaging
Although assessment of regional systolic function is commonly based on visual analysis of myocardial thickening, more recent techniques allow quantitative evaluation of regional systolic function. Those techniques are based on Doppler (Technique of Tissue Doppler Imaging) or on the tracking of the speckles (Technique of Speckle Tracking imaging).