Introduction
Cardiotoxicity, defined by a left ventricular ejection fraction (LVEF)
reduction, is a well-documented side effect of chemotherapeutic
treatment regimens, in particular when anthracycline (ANT) agents are
used [1]. Echocardiography has been proven to be a useful tool in
evaluating the systolic function by LVEF among patients with cancer
[2]. However, using standard echocardiography alone as a measurement
for overall function is not a sensitive tool for detecting subclinical
changes that occur before the development of significant irreversible
myocardial damage [3]. Therefore, the need for early myocardial
injury detection has become critical in managing patients treated with
cancer therapy. Recently, the use of 2D
speckle-tracking echocardiography,
specifically assessment of Global
longitudinal strain (GLS), as a measurement of subtle changes in left
ventricular systolic function, has been shown to be associated with
early diagnosis of cardiotoxicity [4, 5]. Furthermore, both systolic
and diastolic function is essential for normal cardiac function [6].
Diastolic dysfunction development is considered common among patients
with cancer [7], however, no clear evidence has shown that it can
predict future systolic dysfunction and its relationship to early signs
of cardiotoxicity is limited. Currently, diastolic function is evaluated
by a number of parameters including e’, E/e’ ratio, E/A ratio,
deceleration time (DT) and left atrium volume index (LAVI) [8, 9,
10], however, these conventional measurements do not assess the direct
relaxation of LV and have limitations (e.g. angle dependency) [11].
Strain imaging for the evaluation of diastolic function, using global
diastolic strain rate (Dsr), has been shown to have prognostic
information regarding cardiovascular morbidity and mortality [12].
Moreover, Dsr has been used in predicting outcomes in cohorts with heart
failure and acute myocardial infarction, strengthening evidence of its
clinical relevance in these specific populations [13, 14]. However,
the use of longitudinal diastolic strain time (Dst), measuring the time
of lengthening of the myocardium and specifically the change in Dst
during cancer therapies has not been documented yet.
The aim of this study was to evaluate the correlation of Dst with the
routine echocardiography diastolic parameters and to estimate the role
of Dst change for early detection of cardiotoxicity in a breast cancer
patients.