<s>
ST	B-Algorithm
depression	I-Algorithm
refers	O
to	O
a	O
finding	O
on	O
an	O
electrocardiogram	B-Application
,	O
wherein	O
the	O
trace	O
in	O
the	O
ST	B-Algorithm
segment	I-Algorithm
is	O
abnormally	O
low	O
below	O
the	O
baseline	B-Application
.	O
</s>
<s>
Other	O
ischemic	O
heart	O
diseases	O
causing	O
ST	B-Algorithm
depression	I-Algorithm
include	O
:	O
</s>
<s>
Depressed	O
but	O
upsloping	O
ST	B-Algorithm
segment	I-Algorithm
generally	O
rules	O
out	O
ischemia	O
as	O
a	O
cause	O
.	O
</s>
<s>
Also	O
,	O
it	O
can	O
be	O
a	O
normal	O
variant	O
or	O
artifacts	B-Algorithm
,	O
such	O
as	O
:	O
</s>
<s>
Intraventricular	O
conduction	O
abnormalities	O
(	O
e.g.	O
,	O
right	B-Algorithm
or	O
left	O
bundle	B-Algorithm
branch	I-Algorithm
block	I-Algorithm
,	O
WPW	O
,	O
etc	O
.	O
)	O
</s>
<s>
A	O
mnemonic	O
can	O
be	O
used	O
for	O
some	O
causes	O
of	O
ST	B-Algorithm
depression	I-Algorithm
,	O
namely	O
DEPRESSED	O
ST	O
:	O
</s>
<s>
D	O
-	O
Drooping	O
valve	O
(	O
mitral	O
valve	O
prolapse	O
)	O
E	O
-	O
Enlargement	O
of	O
the	O
left	O
ventricle	O
P	O
-	O
Potassium	O
loss	O
R	O
-	O
Reciprocal	O
ST	B-Algorithm
depression	I-Algorithm
(	O
e.g.	O
</s>
<s>
The	O
current	O
flows	O
from	O
the	O
more	O
positive	O
subepicardium	O
to	O
the	O
less	O
positive	O
subendocardium	O
during	O
phase	O
2	O
of	O
the	O
fast	O
fiber	O
type	O
depolarization	O
,	O
which	O
on	O
ECG	B-Application
occurs	O
during	O
ST	B-Algorithm
segment	I-Algorithm
.	O
</s>
<s>
The	O
positive	O
electrodes	O
on	O
the	O
anterior	O
chest	O
wall	O
detect	O
the	O
movement	O
of	O
positive	O
charge	O
away	O
from	O
the	O
electrode	O
and	O
record	O
it	O
as	O
a	O
downward	O
deflection	O
on	O
the	O
ECG	B-Application
paper	O
.	O
</s>
<s>
ST	B-Algorithm
segment	I-Algorithm
depression	O
may	O
be	O
determined	O
by	O
measuring	O
the	O
vertical	O
distance	O
between	O
the	O
patient	O
's	O
trace	O
and	O
the	O
isoelectric	B-Application
line	I-Application
at	O
a	O
location	O
2-3	O
millimeters	O
from	O
the	O
QRS	B-Algorithm
complex	I-Algorithm
.	O
</s>
<s>
In	O
a	O
cardiac	O
stress	O
test	O
,	O
an	O
ST	B-Algorithm
depression	I-Algorithm
of	O
at	O
least	O
1mm	O
after	O
adenosine	O
administration	O
indicates	O
a	O
reversible	O
ischaemia	O
,	O
while	O
an	O
exercise	O
stress	O
test	O
requires	O
an	O
ST	B-Algorithm
depression	I-Algorithm
of	O
at	O
least	O
2mm	O
to	O
significantly	O
indicate	O
reversible	O
ischaemia	O
.	O
</s>
