<s>
In	O
electrocardiography	B-Application
,	O
the	O
ST	B-Algorithm
segment	I-Algorithm
connects	O
the	O
QRS	B-Algorithm
complex	I-Algorithm
and	O
the	O
T	B-Algorithm
wave	I-Algorithm
and	O
has	O
a	O
duration	O
of	O
0.005	O
to	O
0.150	O
sec	O
(	O
5	O
to	O
150	O
ms	O
)	O
.	O
</s>
<s>
It	O
starts	O
at	O
the	O
J	O
point	O
(	O
junction	O
between	O
the	O
QRS	B-Algorithm
complex	I-Algorithm
and	O
ST	B-Algorithm
segment	I-Algorithm
)	O
and	O
ends	O
at	O
the	O
beginning	O
of	O
the	O
T	B-Algorithm
wave	I-Algorithm
.	O
</s>
<s>
However	O
,	O
since	O
it	O
is	O
usually	O
difficult	O
to	O
determine	O
exactly	O
where	O
the	O
ST	B-Algorithm
segment	I-Algorithm
ends	O
and	O
the	O
T	B-Algorithm
wave	I-Algorithm
begins	O
,	O
the	O
relationship	O
between	O
the	O
ST	B-Algorithm
segment	I-Algorithm
and	O
T	B-Algorithm
wave	I-Algorithm
should	O
be	O
examined	O
together	O
.	O
</s>
<s>
The	O
typical	O
ST	B-Algorithm
segment	I-Algorithm
duration	O
is	O
usually	O
around	O
0.08	O
sec	O
(	O
80	O
ms	O
)	O
.	O
</s>
<s>
The	O
ST	B-Algorithm
segment	I-Algorithm
represents	O
the	O
isoelectric	O
period	O
when	O
the	O
ventricles	O
are	O
in	O
between	O
depolarization	O
and	O
repolarization	O
.	O
</s>
<s>
The	O
normal	O
ST	B-Algorithm
segment	I-Algorithm
has	O
a	O
slight	O
upward	O
concavity	O
.	O
</s>
<s>
Flat	O
,	O
downsloping	O
,	O
or	O
depressed	O
ST	B-Algorithm
segments	I-Algorithm
may	O
indicate	O
coronary	O
ischemia	O
.	O
</s>
<s>
ST	B-Algorithm
elevation	I-Algorithm
may	O
indicate	O
transmural	O
myocardial	O
infarction	O
.	O
</s>
<s>
ST	B-Algorithm
depression	I-Algorithm
may	O
be	O
associated	O
with	O
subendocardial	O
myocardial	O
infarction	O
,	O
hypokalemia	O
,	O
or	O
digitalis	O
toxicity	O
.	O
</s>
<s>
In	O
fetal	O
electrocardiography	B-Application
,	O
ST	O
waveform	O
analysis	O
(	O
sometimes	O
abbreviated	O
STAN	O
)	O
is	O
used	O
to	O
get	O
an	O
indication	O
of	O
increasing	O
levels	O
of	O
fetal	O
base	O
deficit	O
.	O
</s>
