<s>
Sinoatrial	B-Algorithm
arrest	I-Algorithm
is	O
a	O
medical	O
condition	O
wherein	O
the	O
sinoatrial	O
node	O
of	O
the	O
heart	O
transiently	O
ceases	O
to	O
generate	O
the	O
electrical	O
impulses	O
that	O
normally	O
stimulate	O
the	O
myocardial	O
tissues	O
to	O
contract	O
and	O
thus	O
the	O
heart	O
to	O
beat	O
.	O
</s>
<s>
This	O
condition	O
can	O
be	O
detected	O
on	O
an	O
electrocardiogram	B-Application
(	O
ECG	B-Application
)	O
as	O
a	O
brief	O
period	O
of	O
irregular	O
length	O
with	O
no	O
electrical	O
activity	O
before	O
either	O
the	O
sinoatrial	O
node	O
resumes	O
normal	O
pacing	O
,	O
or	O
another	O
pacemaker	O
begins	O
pacing	O
.	O
</s>
<s>
If	O
a	O
pacemaker	O
other	O
than	O
the	O
sinoatrial	O
node	O
is	O
pacing	O
the	O
heart	O
,	O
this	O
condition	O
is	O
known	O
as	O
an	O
escape	B-Algorithm
rhythm	I-Algorithm
.	O
</s>
<s>
If	O
no	O
other	O
pacemaker	O
begins	O
pacing	O
during	O
an	O
episode	O
of	O
sinus	B-Algorithm
arrest	I-Algorithm
it	O
becomes	O
a	O
cardiac	O
arrest	O
.	O
</s>
<s>
This	O
condition	O
is	O
sometimes	O
confused	O
with	O
sinoatrial	B-Algorithm
block	I-Algorithm
,	O
a	O
condition	O
in	O
which	O
the	O
pacing	O
impulse	O
is	O
generated	O
,	O
but	O
fails	O
to	O
conduct	O
through	O
the	O
myocardium	O
.	O
</s>
<s>
Junctional	B-Algorithm
escape	I-Algorithm
(	O
rate	O
40	O
–	O
60	O
)	O
:	O
originates	O
near	O
the	O
AV	O
node	O
;	O
a	O
normal	O
P	B-Algorithm
wave	I-Algorithm
is	O
not	O
seen	O
,	O
may	O
occasionally	O
see	O
a	O
retrograde	O
P	B-Algorithm
wave	I-Algorithm
.	O
</s>
<s>
Ventricular	B-Algorithm
escape	I-Algorithm
(	O
rate	O
20	O
–	O
40	O
)	O
:	O
originates	O
in	O
ventricular	O
conduction	B-Algorithm
system	I-Algorithm
;	O
no	O
P	B-Algorithm
wave	I-Algorithm
,	O
wide	O
,	O
abnormal	O
QRS	B-Algorithm
.	O
</s>
