Newer echocardiographic measures of left ventricle
(LV) systolic and diastolic function using myocardial
deformation imaging, strain and strain rate,
may be more sensitive in detecting early or subclinical
cardiac dysfunction before changes are seen in
ejection fraction [16–20]. Strain imaging is assessed
by a speckle tracking technique, which follows the
movement of speckles, natural acoustic markers
within the myocardium in each cardiac cycle
(Fig. 1). Speckles are tracked with automated software,
which allows for rapid and reproducible
assessment of myocardial deformation in three
directions: longitudinal, circumferential and radial.
Clinical studies have shown that strain may be
used to accurately predict cardiotoxicity related to anthracycline and trastuzumab therapy. A study of breast cancer patients receiving
epirubicin showed that a decrease in longitudinal
strain after cycle 3 had the best predictive value for
cardiotoxicity after cycle 6 (sensitivity 84% and
specificity 80%). Longitudinal strain rate increased
the specificity to 90% [24&&]. In patients treated with
trastuzumab, risk prediction with use of global
longitudinal strain, clinical risk factors and LVEF
helped reclassify 29% of patients without events
into a low-risk category and 48% of patients with
events into a high-risk category (area under the
curve¼0.84)