<s>
Premature	B-Algorithm
junctional	I-Algorithm
contractions	I-Algorithm
(	O
PJCs	O
)	O
,	O
also	O
called	O
atrioventricular	O
junctional	O
premature	O
complexes	O
or	O
junctional	O
extrasystole	O
,	O
are	O
premature	O
cardiac	O
electrical	O
impulses	O
originating	O
from	O
the	O
atrioventricular	O
node	O
of	O
the	O
heart	O
or	O
"	O
junction	O
"	O
.	O
</s>
<s>
This	O
area	O
is	O
not	B-Algorithm
the	I-Algorithm
normal	I-Algorithm
but	O
only	O
a	O
secondary	O
source	O
of	O
cardiac	B-Algorithm
electrical	I-Algorithm
impulse	I-Algorithm
formation	I-Algorithm
.	O
</s>
<s>
If	O
more	O
than	O
two	O
such	O
beats	O
are	O
seen	O
,	O
then	O
the	O
condition	O
is	O
termed	O
junctional	B-Algorithm
rhythm	I-Algorithm
.	O
</s>
<s>
On	O
the	O
surface	O
ECG	B-Application
,	O
premature	B-Algorithm
junctional	I-Algorithm
contractions	I-Algorithm
will	O
appear	O
as	O
a	O
normally	O
shaped	O
ventricular	O
complex	O
or	O
QRS	B-Algorithm
complex	I-Algorithm
,	O
not	O
preceded	O
by	O
any	O
atrial	O
complex	O
or	O
P	B-Algorithm
wave	I-Algorithm
or	O
preceded	O
by	O
an	O
abnormal	O
P	B-Algorithm
wave	I-Algorithm
with	O
a	O
shorter	O
PR	B-Algorithm
interval	I-Algorithm
.	O
</s>
<s>
Rarely	O
,	O
the	O
abnormal	O
P	B-Algorithm
wave	I-Algorithm
can	O
follow	O
the	O
QRS	B-Algorithm
.	O
</s>
