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, standard echocardiography alone 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
(2D-STE), specifically 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 routine measurements do not assess the direct
relaxation of the LV and have limitations (e.g. angle dependency)
[11]. Strain imaging for the evaluation of diastolic function, using
global diastolic strain rate, has been shown to have prognostic
information regarding cardiovascular morbidity and mortality [12, 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 pilot study was to evaluate the correlation of Dst with
the routine echocardiography diastolic parameters and to estimate the
role of Dst change during cancer therapy for the early detection of
cardiotoxicity in patients diagnosed with breast cancer.