**14. Unresolved issues**

Although strain analysis is been used with increasing frequency for the evaluation of cardiac function, there are still issues with reproducibility of deformation analysis data, particularly when different echocardiography machines or analysis software is used. Until this issue is resolved the current recommendation is to use the same machine and software when obtaining comparative studies.

The fidelity of the strain data sets is dependent on the quality of the echocardiographic data, unfortunately endocardial contrast enhancing agents cannot be used during strain analysis, therefore strain analysis sometimes has to be obtained with substandard images. The current recommendation is not to report strain values if the echocardiographic images are of poor quality. Hopefully work-around solutions will be found to permit strain analysis with endocardial enhancement agents use.

The current literature supports actionable interventions according to fairly welldefined values of decreased LV ejection fraction, this is not as developed on the characterization of LV dysfunction according to levels of decreased strain values.

Although the literature on strain is fairly robust in aortic stenosis, it is only moderately developed in aortic regurgitation and almost not existent in mixed aortic valve disease.
