Regional wall thickening
| View | Parasternal short axis at the papillary-muscle level (circular ventricle, papillary muscles not wobbling) plus apical views with the sector reduced to the ventricles; each segment in more than one view. |
|---|---|
| Timing | Systolic thickening and endocardial excursion compared across the cycle. |
| Caliper / trace | Visual grading per segment: normal/hyperkinetic (1), hypokinetic (2), akinetic (3), dyskinetic (4); WMSI = mean of scored segments. |
Correct example
Judgement is based on wall thickening rather than endocardial motion alone, with settings adjusted to show thickening; contrast is used when two or more contiguous segments are poorly seen.
Common error
Scoring motion that is really tethering or whole-heart translation, scoring segments that are not visualized, or attributing septal motion abnormalities from LBBB, pacing or RV overload to ischaemia.
Effect on interpretation
Passive deformation can mimic contraction and tethering can mimic dysfunction; regional abnormalities also occur without coronary disease, and septal patterns such as bounce or apical rocking are reported as conduction-related rather than scored as ischaemic.
Why
The wall motion score index averages the scores of visualized segments using the 17-segment model; its validity depends on each segment being seen well enough to judge thickening.