Limitations
First, the subjectivity inherent to the echocardiogram exam can lead to
quantification bias. Small variations in the acquisition at LV apical
level, which do not have an anatomical marker, can result in distorted
values. Image was acquired as the maximum apical SAX view achieved with
still a clear visibility of the myocardial segments. Additionally, we
created another criterion to ratify the correct acquisition, which was
the visualization of at least a trend of a counterclockwise rotation of
these segments, which would be physiologically expected. Finally, it is
important to remind that the examiner was blinded to the patient’s group
allocation.
Second, in this study we used the 2D-STE technique, which would have the
limitation of detecting off-plane movement of the speckles, causing
eventual values underestimation. Theoretically, the use of the
three-dimensional methodology (3D-STE) would have the possibility to
correct this limitation.
Finally, the relatively small sample size, short duration of the
exercise program and the number of training sessions for patients
allocated to the TRAINING group (twice a week), with the aggravation of
low adherence of some patients to the program, may have decreased the
power of the study to demonstrate possible intergroup differences.