Pitfalls	Impact on GLS
Poor endocardial definition	Suboptimal speckle tracking causing error in GLS measurement
Foreshortened apex	Can cause overestimation of apical strain
Not including all LV segments in the sector	Missing strain for the LV segments not included or inadequate tracking of partially included segments
Images captured at different heart rates	Precludes integration of the 3 apical views to derive GLS
Low frame rate (<40 frames/s)	Decreases the quality of the tracking: beware when using compressed DICOM cine loops
Use of contrast	Strain images should be obtained before use of contrast. Use of contrast decreases reliability of the tracking algorithms. There is currently no commercially available software that reliably tracks speckles in the presence of echo contrast, although software is currently under development. Until approved software is available, strain values should not be reported in the presence of echo contrast.