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\begin{document}

\title{The value of STE-LDDSE to detect viable myocardium}



\author[1]{Wei Qian}%
\author[1]{Ran Zhou}%
\author[1]{Tao Chen}%
\author[1]{Xueshan Zhang}%
\author[1]{Yanfeng Ma}%
\affil[1]{Xuzhou Medical University Affiliated Hospital Department of Cardiology}%


\vspace{-1em}



  
  \date{June 02, 2024}


\begingroup
\let\center\flushleft
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\selectlanguage{english}
\begin{abstract}
\textbf{Objective} To explore the value of speckle tracking
echocardiography (STE) with low dose dobutamine stress echocardiography
(LDDSE) for evaluation of viable myocardium (VM) in the acute
ST-elevation myocardial infarction (STEMI) patients with or without type
2 diabetes mellitus (DM). \textbf{Methods} Eighty-five hospitalized
patients with regional wall motion abnormalities (RWMA) according to
routine echocardiography in STEMI, thirty patients with type 2 DM. All
of them were underwent STE associated with LDDSE (STE-LDDSE) prior to
coronary angiography and percutaneous coronary intervention (PCI). Every
segment image was acquired and evaluated by wall-motion analysis. The
images of STE-LDDSE were analyzed quantitatively for peak-systolic
strain (S) and strain rate (Sr), the short axis of radial strain (RS),
radial strain rate (RSr), circumferential strain (CS), circumferential
strain rate (CSr) and the long axis of longitudinal strain (LS),
longitudinal strain rate (LSr) by using the QLAB software. All patients
underwent PCI within one week after completing STE-LDDSE examination,
and echocardiograms were reviewed at 1, 3, and 6 months after surgery.
\textbf{Results} A total of 183 regional wall motion abnormalities
(RWMA) were detected in the DM group, of which 117 (63.93\%) segments
were viable myocardium; 357 RWMA were detected in non DM patients, of
which 248 (69.47\%) segments of viable myocardium were detected by
echocardiography. The sensitivity, accuracy, and specificity of
STE-LDDSE in detecting viable myocardium in DM group were
70.94\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}77.45\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}87.88\% ; 92.31\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}72.73\% and 85.25\% for LS and LSr.
In the non DM group, the sensitivity, specificity, and accuracy of LS
and LSr were 68.95\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}92.66\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}76.19\% ; 77.42\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}88.07\% and 80.67\%,
respectively. Further parallel diagnostic tests were conducted on LS and
LSr parameters. The sensitivity, specificity, and accuracy of detecting
viable myocardium in the DM and non DM groups were
84.62\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}45.45\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}70.49\%, 66.53\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}63.30\% and 65.55\%, respectively,
at rest; They were 84.62\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}45.45\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}70.49\%, 66.53\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}63.30\% and
65.55\%, respectively, during low dose dobutamine stress.
\textbf{Conclusion} STE-LDDSE has a high value of detecting VM. Parallel
diagnostic test for LS and LSr is the best choice in detecting VM in the
patients with STEMI and is more sensitive for the patients with type 2
DM. It will be more effectively to guide the further treatment and to
evaluate the prognosis of the STEMI patients.%
\end{abstract}%



\sloppy


\textbf{The value of STE-LDDSE to detect viable myocardium}

Wei Qian\textsuperscript{a,1}, Ran Zhou\textsuperscript{a}, Tao
Chen\textsuperscript{a,}, Xueshan Zhang\textsuperscript{a}, and Yanfeng
Ma\textsuperscript{a,2}

\textsuperscript{a}Department of Cardiology, The Affiliated Hospital of
Xuzhou Medical University, Xuzhou 221004, China;

\textsuperscript{1}These authors contribute equally

\textsuperscript{2}Corresponding author: Yanfeng Ma

Email:qianw6033@163.com

\textbf{Abstract}

\textbf{Objective}

To explore the value of speckle tracking echocardiography (STE) with low
dose dobutamine stress echocardiography (LDDSE) for evaluation of viable
myocardium (VM) in the acute ST-elevation myocardial infarction (STEMI)
patients with or~without type~2 diabetes mellitus (DM).

\textbf{Methods}

Eighty-five hospitalized patients with regional wall motion
abnormalities (RWMA) according to routine echocardiography in STEMI,
thirty patients with type~2 DM. All of them were underwent STE
associated with LDDSE (STE-LDDSE) prior to coronary angiography and
percutaneous coronary intervention (PCI). Every segment image was
acquired and evaluated by wall-motion analysis. The images of STE-LDDSE
were analyzed quantitatively for peak-systolic strain (S) and strain
rate (Sr), the short axis of radial strain (RS), radial strain rate
(RSr), circumferential strain (CS), circumferential strain rate (CSr)
and the long axis of longitudinal strain (LS), longitudinal strain rate
(LSr) by using the QLAB software. All patients underwent PCI within one
week after completing STE-LDDSE examination, and echocardiograms were
reviewed at 1, 3, and 6 months after surgery.

\textbf{Results}

A total of 183 regional wall motion abnormalities (RWMA) were detected
in the DM group, of which 117 (63.93\%) segments were viable myocardium;
357 RWMA were detected in non DM patients, of which 248 (69.47\%)
segments of viable myocardium were detected by echocardiography. The
sensitivity, accuracy, and specificity of STE-LDDSE in detecting viable
myocardium in DM group were 70.94\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}77.45\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}87.88\% ; 92.31\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}72.73\%
and 85.25\% for LS and LSr. In the non DM group, the sensitivity,
specificity, and accuracy of LS and LSr were 68.95\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}92.66\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}76.19\% ;
77.42\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}88.07\% and 80.67\%, respectively.

Further parallel diagnostic tests were conducted on LS and LSr
parameters. The sensitivity, specificity, and accuracy of detecting
viable myocardium in the DM and non DM groups were
84.62\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}45.45\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}70.49\%, 66.53\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}63.30\% and 65.55\%, respectively,
at rest; They were 84.62\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}45.45\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}70.49\%, 66.53\%\begin{CJK}{UTF8}{gbsn}、\end{CJK}\selectlanguage{english}63.30\% and
65.55\%, respectively, during low dose dobutamine stress.

\textbf{Conclusion}

STE-LDDSE has a high value of detecting VM. Parallel diagnostic test for
LS and LSr is the best choice in detecting VM in the patients with STEMI
and is more sensitive for the patients with type 2 DM. It will be more
effectively to guide the further treatment and to evaluate the prognosis
of the STEMI patients.

\textbf{Key words} speckle tracking echocardiography; low dose
dobutamine stress echocardiography; ST-elevation myocardial infarction;
diabetes mellitus; viable myocardium

\textbf{Introduction}

DM is a systemic metabolic disorder, and more than 70\% of diabetic
patients develop coronary heart disease (CHD), which exhibits a wider
range and faster progression of coronary artery disease compared to
non-diabetic individuals. The main lesions in CHD occur in the
epicardium, whereas in DM, the primary lesions involve the myocardium
and microvasculature. When both conditions coexist, the aforementioned
lesions may be more extensive and severe. Clinical observations have
shown that DM patients with concomitant CHD have a higher prevalence and
severity of multi-vessel and diffuse coronary lesions compared to
non-diabetic patients\textsuperscript{{[}1-2{]}}

Studies have confirmed that after acute myocardial infarction (AMI), the
region of RWMA comprises not only necrotic myocardium but also viable
myocardium, including stunned myocardium and hibernating
myocardium\textsuperscript{{[}3-4{]}}. So far, there are three main
approaches used to identify viable myocardium\textsuperscript{{[}4{]}}:
(1) Assessment of myocardial cellular metabolism, including oxidative
metabolism, glucose metabolism, and fatty acid metabolism; (2)
Evaluation of myocardial perfusion; (3) Monitoring of myocardial
contractile reserve. Among these, dobutamine stress echocardiography
(DSE) is internationally recognized as the standard method for
monitoring myocardial contractile reserve and is widely employed.

At present, STE-LDDSE offers significant advantages over traditional
methods for assessing viable myocardium\textsuperscript{{[}5-8{]}}. It
mainly tracks the speckles of high-frame-rate two-dimensional images
frame by frame, allowing for the calculation and delineation of
myocardial motion velocity and deformation. By observing myocardial
motion trajectories, it accurately measures myocardial fiber motion
strain, strain rate, and rotation angles. Due to its angle-independent
nature, STE can provide more accurate assessments of local and global
myocardial function, making it highly valuable for detecting viable
myocardium. The combination of STE and LDDSE further enhances the
sensitivity and specificity, maximizing the detection of viable
myocardium\textsuperscript{{[}9-12{]}}.

\textbf{Results}

\textbf{Basic Clinical Characteristics of Patients}

A total of 85 patients were included in the study, including 30 patients
in the DM group and 55 patients in the non-DM group. All patients
successfully completed the examinations, and satisfactory cardiac
ultrasound images were obtained (Fig. 1A and B). No malignant
arrhythmias or cardiovascular events occurred during the entire
examination process.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

\textbf{Figure 1 STE method for measuring LSr}

(A) represents the pre-LDDSE condition, while (B) shows the post-LDDSE
condition. Arrow 1 indicates the apical region of the interventricular
septum, and arrow 2 represents the time curve of peak LS during systole
in the apical region of the interventricular septum

\textbf{Changes in Hemodynamic Parameters pre/post LDDSE}

The comparison of heart rate and blood pressure pre/post LDDSE in the 85
patients (Table S1). The results showed an increase in heart rate after
medication, while blood pressure did not show significant changes.

\textbf{Analysis of Echocardiographic Wall Motion}

A total of 1,445 segments from the 85 patients were included in the
study, including 540 segments with RWMA. After LDDSE in the DM group,
119 segments were classified as viable myocardium, and 64 segments were
classified as non-viable myocardium. In the non-DM group, 189 segments
were classified as viable myocardium, and 168 segments were classified
as non-viable myocardium (Table S2).

Follow-up echocardiography was performed at 1, 3, and 6 months after
PCI. Based on the ''gold standard'', 540 segments were followed up,
which 365 segments classified as viable myocardium and 175 segments
classified as non-viable myocardium. Among the 183 segments followed up
in the DM group, which 117 segments were classified as viable myocardium
and 66 segments were classified as non-viable myocardium. In the non-DM
group, 357 segments were followed up, which 248 segments classified as
viable myocardium and 109 segments classified as non-viable myocardium
(Table S3).

Comparison with the ''gold standard'' showed that the sensitivity,
specificity, and accuracy of LDDSE semi-quantitative visual assessment
for evaluating viable myocardium in the DM group were 70.09\%, 43.94\%,
and 60.66\%, respectively. In the non-DM group, the sensitivity,
specificity, and accuracy were 55.65\%, 53.21\%, and 54.90\%,
respectively. The DM group had higher sensitivity and accuracy compared
to the non-DM group, with statistically significant differences
(\emph{P} \textless{} 0.05). However, the specificity was lower in the
DM group compared to the non-DM group, with statistically significant
differences (\emph{P} \textless{} 0.05).

\textbf{The Value of STE-LDDSE in Evaluating Viable Myocardium}

It involves quantitative analysis of S and Sr parameters in 540 segments
with RWMA by QLAB 8.1 software. Binary logistic regression analysis was
performed to evaluate the value of different S and Sr parameters at rest
for detecting viable myocardium. The results showed that CS, LS, and LSr
had significant value (\emph{P} \textless{} 0.05) in detecting viable
myocardium (Table 1).\selectlanguage{english}
\begin{longtable}[]{@{}lll@{}}
\toprule
factor & B & \emph{P} value\tabularnewline
RSr\emph{\textsubscript{rest}} CS\emph{\textsubscript{rest}}
LS\emph{\textsubscript{rest}} LSr\emph{\textsubscript{rest}} & -1.310
0.223 0.155 0.941 & <0.001 <0.001 0.009 0.022\tabularnewline
\bottomrule
\end{longtable}

\textbf{Table 1: The value of using binary logistic stepwise regression
analysis to detect viable myocardium using different S and Sr parameters
in the resting state.}

Subsequently, LS, LSr and ROC curves were plotted to determine the
optimal cutoff points for detecting viable myocardium using STE.
Accordingly, sensitivity, specificity, and accuracy were calculated
(Fig. 2A-D, Table 2 and 3).

In the DM group, the cutoff point for LS\textsubscript{rest} was
determined to be -13.27, with 46 out of 117 segments classified as
viable myocardium (LS\emph{\textsubscript{rest}} [?] -13.27) and 71
segments as non-viable myocardium
(LS\emph{\textsubscript{rest}}\textgreater{} -13.27) according to the
gold standard. Similarly, for LS\emph{\textsubscript{LDDSE}} in the DM
group, the cutoff point was -13.81, with 83 segments classified as
viable myocardium (LSLDDSE [?] -13.81) and 34 segments as non-viable
myocardium (LS\emph{\textsubscript{LDDSE}} \textgreater{} -13.81). In
terms of LSr\emph{\textsubscript{rest,}} the cutoff point was -0.875,
resulting in 98 segments classified as viable myocardium
(LSr\emph{\textsubscript{rest}} [?] -0.875) and 19 segments as non-viable
myocardium (LSr\emph{\textsubscript{rest}} \textgreater{} -0.875)
according to the gold standard. In the DM group,
LSr\emph{\textsubscript{LDDSE}} had a cutoff point of -1.12, with 108
segments classified as viable myocardium
(LSr\emph{\textsubscript{LDDSE}} [?] -1.12) and 9 segments as non-viable
myocardium (LSr\emph{\textsubscript{LDDSE}} \textgreater{} -1.12).

In the non-DM group, the cutoff point for
LS\emph{\textsubscript{rest}}was -12.33, with 123 out of 248 segments
classified as viable myocardium (LS\emph{\textsubscript{rest}} [?] -12.33)
and 125 segments as non-viable myocardium (LS\emph{\textsubscript{rest}}
\textgreater{} -12.33) according to the gold standard. Similarly, for
LSLDDSE in the non-DM group, the cutoff point was -14.075, with 171
segments classified as viable myocardium (LS\emph{\textsubscript{LDDSE}}
[?] -14.075) and 77 segments as non-viable myocardium
(LS\emph{\textsubscript{LDDSE}}\textgreater{} -14.075). Regarding
LSr\emph{\textsubscript{rest}} , the cutoff point was -1.075, resulting
in 156 segments classified as viable myocardium
(LSr\emph{\textsubscript{rest}} [?] -1.075) and 92 segments as non-viable
myocardium (LSr\emph{\textsubscript{rest}} \textgreater{} -1.075)
according to the gold standard. In the non-DM group,
LSr\emph{\textsubscript{LDDSE}} had a cutoff point of -1.305, with 192
segments classified as viable myocardium
(LSr\emph{\textsubscript{LDDSE}} [?] -1.305) and 56 segments as non-viable
myocardium (LSr\emph{\textsubscript{LDDSE}} \textgreater{} -1.305)
according to the gold ststandard.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

\textbf{Figure 2 ROC curve for detecting viable myocardium}

and (B) display the ROC curves of LS and LSr in the DM group for
detecting viable myocardium during resting and LDDSE. (C) and (D) show
the ROC curves of LS and LSr in the non-DM group for detecting viable
myocardium during resting and LDDSE.\selectlanguage{english}
\begin{longtable}[]{@{}lllllll@{}}
\toprule
status & sensibility (\%) & sensibility (\%) & specificity (\%) &
specificity (\%) & accuracy (\%) & accuracy (\%)\tabularnewline
& DM & non-DM & DM & non-DM & DM & non-DM\tabularnewline
LS\emph{\textsubscript{rest}} & 39.32\textsuperscript{\$} & 49.60 &
89.39\textsuperscript{\$} & 77.98 & 57.38\selectlanguage{greek}\textsuperscript{Δ} &
58.26\tabularnewline
LS\emph{\textsubscript{LDDSE}} & 70.94\selectlanguage{greek}\textsuperscript{Δ} & 68.95 &
87.88\textsuperscript{\$} & 92.66 & 77.45\selectlanguage{greek}\textsuperscript{Δ} &
76.19\tabularnewline
McNemar's \textsuperscript{2} & 28.8 & 30.681 & 0 & 14.062 & 26.327 &
10.92\tabularnewline
\emph{P} & 8.025e-08 & 3.042e-08 & 1 & 0.0001768 & 2.882e-07 &
0.0009511\tabularnewline
\bottomrule
\end{longtable}

\textsuperscript{\$}DM compared with non-DM, \emph{P}
\textless{}0.05,\selectlanguage{greek}\textsuperscript{Δ} \selectlanguage{english}Compare with resting, \emph{P}
\textgreater{}0.05

\textbf{Table 2:The value of detecting LS parameters in STE for
diagnosing viable myocardium.}\selectlanguage{english}
\begin{longtable}[]{@{}lllllll@{}}
\toprule
status & sensibility (\%) & sensibility (\%) & specificity (\%) &
specificity (\%) & accuracy (\%) & accuracy (\%)\tabularnewline
& DM & non-DM & DM & non-DM & DM & non-DM\tabularnewline
LSr\emph{\textsubscript{rest}} & 83.76\textsuperscript{\$} & 62.90 &
45.45\textsuperscript{\$} & 66.06 & 69.95\textsuperscript{\$} &
63.87\tabularnewline
LSr\emph{\textsubscript{LDDSE}} & 92.31\textsuperscript{\$} & 77.42 &
72.73\textsuperscript{\$} & 88.07 & 85.25\textsuperscript{\$} &
80.67\tabularnewline
McNemar's \textsuperscript{2} & 22.042 & 16.118 & 12.042 & 22.042 &
1.0652 & 1.21\tabularnewline
\emph{P} & 2.668e-06 & 5.95e-05 & 0.0005202 & 2.668e-06 & 0.302 &
0.2713\tabularnewline
\bottomrule
\end{longtable}

\textsuperscript{\$}DM compared with non-DM, \emph{P}
\textless{}0.05,\selectlanguage{greek}\textsuperscript{Δ} \selectlanguage{english}Compare with resting, \emph{P}
\textgreater{}0.05

\textbf{Table 3:The value of detecting LSr parameters in STE for
diagnosing viable myocardium.}

Further parallel diagnostic testing was performed on the LS and LSr
parameters at rest. In the DM group, the sensitivity, specificity, and
accuracy were found to be 84.62\%, 45.45\%, and 70.49\%, respectively.
In the non-DM group, the sensitivity, specificity, and accuracy were
66.53\%, 63.30\%, and 65.55\%, respectively. The DM group showed higher
sensitivity and accuracy compared to the non-DM group, with
statistically significant differences. However, the DM group had lower
specificity compared to the non-DM group, also with statistically
significant differences (Table 4 and 6).Parallel diagnostic testing was
also conducted on the LS and LSr parameters under stress conditions. In
the DM group, the sensitivity, specificity, and accuracy were 92.31\%,
60.70\%, and 84.15\%, respectively. In the non-DM group, the
sensitivity, specificity, and accuracy were 84.27\%, 81.65\%, and
83.47\%, respectively (Table 5 and 6). The DM group exhibited higher
sensitivity and accuracy compared to the non-DM group, with
statistically significant differences. However, the DM group had lower
specificity compared to the non-DM group, also with statistically
significant differences. The accuracy was higher in the DM group, but
the difference was not statistically significant.

In the DM group, STE demonstrated higher sensitivity, specificity, and
accuracy for detecting viable myocardium under stress conditions
compared to rest. Additionally, STE at rest showed higher sensitivity
and accuracy compared to the semi-quantitative visual assessment of
LDDSE, with statistically significant differences. The specificity of
STE at rest was higher than that of LDDSE, but the difference was not
statistically significant. In the non-DM group, STE at stress showed
higher sensitivity, specificity, and accuracy for detecting viable
myocardium compared to rest, with statistically significant differences.
STE at rest also exhibited higher sensitivity, specificity, and accuracy
compared to LDDSE, with statistically significant differences (Table 6).\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
LS\emph{\textsubscript{rest}} +LSr\emph{\textsubscript{rest}} & gold
standard & gold standard & total & total\tabularnewline
& viable myocardium & Non-viable myocardium & &\tabularnewline
viable myocardium\textsuperscript{a} & 99 & 36 & 36 & 135\tabularnewline
viable myocardium\textsuperscript{b} & 165 & 40 & 40 &
205\tabularnewline
Non-viable myocardium\textsuperscript{a} & 18 & 30 & 30 &
48\tabularnewline
Non-viable myocardium\textsuperscript{b} & 83 & 69 & 69 &
152\tabularnewline
total\textsuperscript{a} & 117 & 66 & 66 & 183\tabularnewline
total\textsuperscript{b} & 248 & 109 & 109 & 357\tabularnewline
\bottomrule
\end{longtable}

\textsuperscript{a} DM, \textsuperscript{b} non-DM

\textbf{Table 4:Conducting parallel diagnostic trials using
LS\emph{\textsubscript{rest}} and LSr\emph{\textsubscript{rest}} in
combination to detect viable myocardium.}\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
LS\emph{\textsubscript{LDDSE}}+LSr\emph{\textsubscript{LDDSE}} & gold
standard & gold standard & gold standard & total\tabularnewline
& viable myocardium & viable myocardium & Non-viable myocardium
&\tabularnewline
viable myocardium\textsuperscript{a} & 108 & 20 & 20 &
128\tabularnewline
viable myocardium\textsuperscript{b} & 209 & 20 & 20 &
229\tabularnewline
Non-viable myocardium\textsuperscript{a} & 9 & 46 & 46 &
55\tabularnewline
Non-viable myocardium\textsuperscript{b} & 39 & 89 & 89 &
128\tabularnewline
total\textsuperscript{a} & 117 & 66 & 66 & 183\tabularnewline
total\textsuperscript{b} & 248 & 109 & 109 & 357\tabularnewline
\bottomrule
\end{longtable}

\textsuperscript{a}DM, \textsuperscript{b} non-DM

\textbf{Table 5:Conducting parallel diagnostic trials using
LS\emph{\textsubscript{LDDSE}} and LS\emph{\textsubscript{LDDSE}} in
combination to detect viable myocardium.}\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
status & sensibility (\%) & specificity (\%) & accuracy
(\%)\tabularnewline
LDDSE semi-quantitative\textsuperscript{a} LDDSE
semi-quantitative\textsuperscript{b} & 70.09\textsuperscript{\$} 55.69 &
43.94\textsuperscript{\$} 53.21 & 60.66 54.90\tabularnewline
Resting STE\textsuperscript{a} Resting STE\textsuperscript{b} &
84.62\textsuperscript{*\$} 66.53\textsuperscript{*} &
45.45\textsuperscript{\#\$} 63.30\textsuperscript{*} & 70.49*
65.55*\tabularnewline
STE+LDDSE\textsuperscript{a} STE+LDDSE\textsuperscript{b} &
92.31\selectlanguage{greek}\textsuperscript{*Δ\$}\selectlanguage{english} 84.27\selectlanguage{greek}\textsuperscript{*Δ} &
60.70\selectlanguage{greek}\textsuperscript{*Δ\$}\selectlanguage{english} 81.65\selectlanguage{greek}\textsuperscript{*Δ} &
84.15\selectlanguage{greek}\textsuperscript{*Δ} \selectlanguage{english}83.47\selectlanguage{greek}\textsuperscript{*Δ}\selectlanguage{english}\tabularnewline
\bottomrule
\end{longtable}

\textsuperscript{a} DM, \textsuperscript{*} compared with LDDSE
semi-quantitative, \emph{P} \textless{}0.05,
\textsuperscript{\#}compared with LDDSE semi-quantitative, \emph{P}
\textgreater{}0.05, \selectlanguage{greek}\textsuperscript{Δ}\selectlanguage{english}\emph{P} \textless{}0.05 compared
to resting time; \textsuperscript{b}non-DM, \textsuperscript{*} compared
with LDDSE semi-quantitative,\emph{P} \textless{}0.05,
\selectlanguage{greek}\textsuperscript{Δ} \selectlanguage{english}\emph{P} \textless{}0.05 compared to resting time

\textsuperscript{\$}DM compared with non-DM, \emph{P} \textless{}0.05

\textbf{Table 6:The value of different diagnostic methods in diagnosing
viable myocardium}

\textbf{Reproducibility Test}

To assess inter-observer variability, two experienced ultrasound
examiners analyzed S and Sr parameters for 39 RWMA segments in 6
randomly selected subjects, resulting in an inter-observer variability
of 5.3\%. Intra-observer variability was assessed by having the same
ultrasound examiner analyze S and Sr parameters for 50 RWMA segments in
8 randomly selected subjects, resulting in an intra-observer variability
of 4.9\%. These findings indicate good reproducibility of the STE
measurements.

\textbf{Discussion}

Recent studies have highlighted the presence of viable myocardium,
including stunned and hibernating myocardium, within areas of RWMA after
AMI. Viable myocardium refers to myocardial tissue that can recover its
function, either partially or completely, upon restoration of blood
supply. Effective revascularization can lead to functional recovery of
viable myocardium, improving clinical symptoms and prognosis. On the
other hand, non-viable myocardium does not regain its function even with
successful revascularization. Therefore, the assessment of myocardial
viability is crucial for guiding treatment decisions in patients with
STEMI. The improvement of RWMA contraction function after PCI is widely
regarded as the ''gold standard'' for determining viable
myocardium\textsuperscript{{[}13{]}}.

It is important to note that this study had a small sample size and
focused solely on RWMA, which may have limited the detection of viable
myocardium in segments with normal wall motion. To enhance the study's
validity and generalizability, it is recommended to expand the sample
size in future research. Additionally, the follow-up echocardiography
assessed improvement in wall motion compared to baseline, considering an
improvement of [?]1 grade as indicative of viable myocardium. However,
further analysis comparing improvements of [?]1 grade to improvements of
[?]2 grades or more was not conducted due to the limited number of
eligible segments.

Future studies should consider including segments with normal wall
motion to avoid potential underdiagnosis of viable myocardium.
Additionally, exploring more comprehensive criteria for assessing viable
myocardium, such as improvements of [?]2 grades or more, could provide
further insights into the extent of functional recovery. These
considerations would contribute to a more comprehensive understanding of
myocardial viability assessment and its implications for clinical
decision-making.

STE can track the movement of the myocardeum by recognizing the
echo-speckle signal of the myocardeum in the image. This technology can
evaluate the myocardial segmental strain from multiple directions
without angle dependence, and can evaluate the local or global
myocardial function changes . The research showed that longitudinal peak
strain decreased during the acute phase and LS increased after
contraction in patients with ST segment elevation myocardial infarction.
It was concluded that the best indexes for evaluating transmural
infarction in cardiac myotameric segments were longitudinal peak strain
and post-systolic LS, with truncation values of -13\% (AUC=0.86) and 8\%
(AUC=0.84), respectively, and these two indexes could well predict the
improvement of myocardial function 6 months
later\textsuperscript{{[}14{]}}. Meanwhile, some scholars have applied
three-dimensional speckle tracking imaging to evaluate the viable
myocardium of myocardial infarction patients, and found that the cutoff
value, sensitivity, and specificity of segmental radial strain detection
for survival myocardium were 11.1\%, 0.951, and 0.534, respectively. The
cutoff value, sensitivity, and specificity of LS were 14.3\%, 0.652, and
0.657, respectively. The cutoff value, sensitivity, and specificity of
area strain were 23.2\%, 0.915, and 0.828, respectively. Among them, the
sensitivity and specificity of area strain were
higher\textsuperscript{{[}15{]}}. However, the current frame rate of 3D
strain imaging is still not high enough, and some useful information may
be lost.

LDDSE is currently internationally recognized as the standard method for
detecting the reserve of viable myocardial contractile function. The
improvement of RWMA segments in resting echocardiography after LDDSE
indicates the presence of viable myocardium in that segment. Dobutamine
(dobu) is a synthetic catecholamine, which has a relative excitatory
effect on \selectlanguage{greek}β\selectlanguage{english}1 receptor, but a weak excitatory effect on \selectlanguage{greek}β\selectlanguage{english}2 receptor and \selectlanguage{greek}α
\selectlanguage{english}receptor. Small dose of dobu([?]10 ug/kg/min) mainly excitates \selectlanguage{greek}β\selectlanguage{english}1
receptor, has little effect on blood pressure and heart rate, enhances
myocardial contractility and induces myocardial ischemia, which has
important value in evaluating myocardial survival. In 1997, the using of
LDDSE to detect myocardial viability in patients with acute myocardial
infarction has been reported to have objective sensitivity and
accuracy\textsuperscript{{[}16{]}}.

The development of imaging technology has provided an important method
for evaluating the viable myocardium of myocardial infarction patients.
Currently, there are many methods available, and combined with clinical
research, a single method has limited diagnostic value. Therefore,
clinical practice is gradually inclined towards joint diagnostic
evaluation. Both of these methods are non-invasive and highly feasible
methods for detecting viable myocardial muscle. The sensitivity,
specificity and accuracy of SET-LDDSE were significantly improved
compared with the resting state. Studies have demonstrated that STE is
accurate, reliable, and reproducible, with little intra-observer and
inter-observer variation. Compare the diagnostic results with the ''gold
standard'', the study results showed that STE-LDDSE had great value in
the diagnostic accuracy, specificity and sensitivity of viable
myocardium in patients with myocardial infarction, suggesting that
STE-LDDSE should be the first choice in the evaluation of viable
myocardium in patients with myocardial infarction.

In summary, compared to traditional and single examination methods,
STE-LDDSE has higher sensitivity, specificity, and accuracy, which is
more helpful in guiding patients to effectively evaluate viable
myocardium before PCI, and has a certain guiding role in blood vessel
reconstruction and prognosis.

\textbf{Conclusion}

STE-LDDSE detection has certain clinical value in assessing the
viability of myocardium in STEMI patients, superior to semi-quantitative
visual estimation of LDDSE and resting STE.

STE-LDDSE detection is more sensitive in assessing the viability of
myocardium in DM patients with concurrent STEMI compared to non-DM
patients.

3. Preoperative STE-LDDSE detection in STEMI patients is safe and
feasible for assessing the viability of myocardium before coronary
revascularization, providing certain guidance for reestablishing blood
flow.

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\textbf{Materials and Methods}

\textbf{Reagents}

Dobutamine: Shanghai First Biochemical Pharmaceutical Co., Ltd.,
20mg:2ml*10 vials, National Drug Approval Number H3102190.

\textbf{Statistical Analysis}

SPSS 16.0 statistical analysis software was used for statistical
analysis. All continuous data were expressed as mean \selectlanguage{ngerman}± standard
deviation (±S). Paired data following a normal distribution were
analyzed using t-tests, while independent samples were analyzed using
independent sample t-tests. Binary logistic regression analysis was
performed to select valuable S and Sr parameters for detecting viable
myocardium. Receiver operating characteristic (ROC) curves were used to
calculate the area under the curve (AUC) and determine the optimal
cutoff points, sensitivity, specificity, and accuracy for diagnosing
viable myocardium. Chi-square test was used for intergroup comparison of
rates. A p-value \selectlanguage{english}[?]0.05 was considered statistically significant, with a
significance level of \selectlanguage{greek}α\selectlanguage{english}=0.05.

Additional methods can be found in SI Appendix, SI Materials and
Methods.

\textbf{ACKNOWLEDGEMENTS}

This work is not supported by funds

\textbf{AUTHOR CONTRIBUTIONS}

Author contributions: W.Q., and Y.M. designed research; W.Q., R.Z., T.C.
and Y.M.; provided samples; X.Z., and Y.M.; performed research; W.Q.,
and Y.M. analyzed data; W.Q., and Y.M. wrote the paper.

\textbf{COMPETING INTERESTS}

The authors declare no competing interests.

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