<s>
Ectopic	B-Algorithm
beat	I-Algorithm
is	O
a	O
disturbance	O
of	O
the	O
cardiac	B-Algorithm
rhythm	I-Algorithm
frequently	O
related	O
to	O
the	O
electrical	B-Algorithm
conduction	I-Algorithm
system	I-Algorithm
of	I-Algorithm
the	I-Algorithm
heart	I-Algorithm
,	O
in	O
which	O
beats	O
arise	O
from	O
fibers	O
or	O
group	O
of	O
fibers	O
outside	O
the	O
region	O
in	O
the	O
heart	O
muscle	O
ordinarily	O
responsible	O
for	O
impulse	O
formation	O
(	O
i.e.	O
,	O
the	O
sinoatrial	O
node	O
)	O
.	O
</s>
<s>
An	O
ectopic	B-Algorithm
beat	I-Algorithm
can	O
be	O
further	O
classified	O
as	O
either	O
a	O
premature	B-Error_Name
ventricular	I-Error_Name
contraction	I-Error_Name
(	O
PVC	O
)	O
,	O
or	O
a	O
premature	B-Algorithm
atrial	I-Algorithm
contraction	I-Algorithm
(	O
PAC	O
)	O
.	O
</s>
<s>
Ectopic	B-Algorithm
beats	I-Algorithm
are	O
more	O
common	O
during	O
periods	O
of	O
psychological	O
stress	O
,	O
exercise	O
or	O
debility	O
;	O
they	O
may	O
also	O
be	O
triggered	O
by	O
consumption	O
of	O
some	O
food	O
like	O
carbohydrates	O
,	O
strong	O
cheese	O
,	O
or	O
chocolate	O
.	O
</s>
<s>
It	O
is	O
a	O
form	O
of	O
cardiac	B-Application
arrhythmia	I-Application
in	O
which	O
ectopic	B-Algorithm
foci	I-Algorithm
within	O
either	O
ventricular	O
or	O
atrial	O
myocardium	O
,	O
or	O
from	O
finer	O
branches	O
of	O
the	O
electric	O
transduction	O
system	O
,	O
cause	O
additional	O
beats	O
of	O
the	O
heart	O
.	O
</s>
<s>
Ectopic	B-Algorithm
beats	I-Algorithm
are	O
considered	O
normal	O
and	O
are	O
not	O
indicative	O
of	O
cardiac	O
pathology	O
.	O
</s>
<s>
Ectopic	B-Algorithm
beats	I-Algorithm
often	O
remain	O
undetected	O
and	O
occur	O
as	O
part	O
of	O
minor	O
errors	O
in	O
the	O
heart	B-Algorithm
conduction	I-Algorithm
system	I-Algorithm
.	O
</s>
<s>
Ectopic	B-Algorithm
beats	I-Algorithm
are	O
a	O
type	O
of	O
cardiac	B-Application
arrhythmias	I-Application
,	O
which	O
is	O
a	O
variety	O
of	O
cardiac	O
abnormalities	O
relating	O
to	O
rate	O
or	O
rhythm	O
of	O
the	O
cardiac	O
cycle	O
.	O
</s>
<s>
Ectopic	B-Algorithm
beats	I-Algorithm
may	O
become	O
more	O
frequent	O
during	O
anxiety	O
,	O
panic	O
attack	O
,	O
and	O
the	O
fight-or-flight	O
response	O
due	O
to	O
the	O
increase	O
in	O
sympathetic	O
nervous	O
activity	O
or	O
due	O
to	O
parasympathetic	O
failure	O
,	O
stimulating	O
either	O
more	O
frequent	O
or	O
more	O
vigorous	O
contractions	O
and	O
increasing	O
stroke	O
volume	O
.	O
</s>
<s>
The	O
consumption	O
of	O
nicotine	B-Operating_System
,	O
alcohol	O
,	O
epinephrine	O
and	O
caffeine	B-Application
may	O
also	O
increase	O
the	O
incidence	O
of	O
ectopic	B-Algorithm
beats	I-Algorithm
,	O
due	O
to	O
their	O
influence	O
on	O
the	O
action	O
of	O
cardiomyocytes	O
.	O
</s>
