<s>
Technicians	O
who	O
use	O
ultrasound	B-Application
to	O
examine	O
the	O
heart	O
chambers	O
,	O
valves	O
,	O
and	O
vessels	O
are	O
referred	O
to	O
as	O
cardiac	B-Algorithm
sonographers	I-Algorithm
.	O
</s>
<s>
They	O
use	O
ultrasound	B-Application
instrumentation	O
to	O
create	O
images	O
called	O
echocardiograms	B-Application
.	O
</s>
<s>
An	O
echocardiogram	B-Application
may	O
be	O
performed	O
while	O
the	O
patient	O
is	O
either	O
resting	O
or	O
physically	O
active	O
.	O
</s>
<s>
Cardiac	B-Algorithm
sonographers	I-Algorithm
also	O
may	O
assist	O
transesophageal	B-Algorithm
echocardiography	I-Algorithm
,	O
which	O
involves	O
placing	O
a	O
tube	O
in	O
the	O
patient	O
's	O
esophagus	O
to	O
obtain	O
ultrasound	B-Application
images	O
.	O
</s>
<s>
Then	O
they	O
perform	O
a	O
noninvasive	O
procedure	O
using	O
ultrasound	B-Application
instrumentation	O
to	O
record	O
vascular	O
information	O
such	O
as	O
vascular	O
blood	O
flow	O
,	O
blood	O
pressure	O
,	O
changes	O
in	O
limb	O
volume	O
,	O
oxygen	O
saturation	O
,	O
cerebral	O
circulation	O
,	O
peripheral	O
circulation	O
,	O
and	O
abdominal	O
circulation	O
.	O
</s>
<s>
Cardiovascular	O
technicians	O
who	O
obtain	O
EKGs	B-Application
are	O
known	O
as	O
electrocardiograph	B-Application
(	O
or	O
EKG	B-Application
)	O
technicians	O
.	O
</s>
<s>
To	O
take	O
a	O
basic	O
EKG	B-Application
,	O
which	O
traces	O
electrical	O
impulses	O
transmitted	O
by	O
the	O
heart	O
,	O
technicians	O
attach	O
electrodes	O
to	O
the	O
patient	O
's	O
chest	O
,	O
arms	O
,	O
and	O
legs	O
,	O
and	O
then	O
manipulate	O
switches	O
on	O
an	O
EKG	B-Application
machine	O
to	O
obtain	O
a	O
reading	O
.	O
</s>
<s>
An	O
EKG	B-Application
is	O
printed	O
out	O
for	O
interpretation	O
by	O
the	O
physician	O
.	O
</s>
<s>
EKG	B-Algorithm
technicians	I-Algorithm
with	O
advanced	O
training	O
setup	O
Holter	O
monitor	O
and	O
stress	O
testing	O
.	O
</s>
<s>
For	O
Holter	O
monitoring	O
,	O
technicians	O
place	O
electrodes	O
on	O
the	O
patient	O
's	O
chest	O
and	O
attach	O
a	O
portable	O
EKG	B-Application
monitor	O
to	O
the	O
patient	O
's	O
belt	O
.	O
</s>
<s>
Physicians	O
use	O
the	O
output	O
from	O
the	O
scanner	O
to	O
diagnose	O
heart	O
ailments	O
,	O
such	O
as	O
heart	O
rhythm	O
abnormalities	O
or	O
problems	O
with	O
pacemakers	B-Device
.	O
</s>
<s>
For	O
a	O
treadmill	O
stress	O
test	O
,	O
EKG	B-Algorithm
technicians	I-Algorithm
document	O
the	O
patient	O
's	O
medical	O
history	O
,	O
explain	O
the	O
procedure	O
,	O
connect	O
the	O
patient	O
to	O
an	O
EKG	B-Application
monitor	O
,	O
and	O
obtain	O
a	O
baseline	O
reading	O
and	O
resting	O
blood	O
pressure	O
.	O
</s>
<s>
The	O
position	O
is	O
generally	O
unlicensed	O
and	O
skills	O
are	O
learned	O
on	O
the	O
job	O
;	O
however	O
,	O
two	O
-	O
and	O
four-year	O
training	O
programs	O
to	O
learn	O
advanced	O
ECG	B-Application
technical	O
skills	O
are	O
available	O
at	O
junior	O
colleges	O
and	O
community	O
colleges	O
.	O
</s>
