<s>
Bifascicular	B-Algorithm
block	I-Algorithm
is	O
a	O
conduction	B-Algorithm
abnormality	O
in	O
the	O
heart	O
where	O
two	O
of	O
the	O
three	O
main	O
fascicles	O
of	O
the	O
His/Purkinje	B-Algorithm
system	I-Algorithm
are	O
blocked	O
.	O
</s>
<s>
Most	O
commonly	O
,	O
it	O
refers	O
to	O
a	O
combination	O
of	O
right	B-Algorithm
bundle	I-Algorithm
branch	I-Algorithm
block	I-Algorithm
(	O
RBBB	B-Algorithm
)	O
and	O
either	O
left	O
anterior	O
fascicular	O
block	O
(	O
LAFB	O
)	O
or	O
left	B-Algorithm
posterior	I-Algorithm
fascicular	I-Algorithm
block	I-Algorithm
(	O
LPFB	B-Algorithm
)	O
,	O
with	O
the	O
former	O
being	O
more	O
common	O
.	O
</s>
<s>
Some	O
authors	O
consider	O
left	O
bundle	O
branch	O
block	O
(	O
LBBB	O
)	O
to	O
be	O
a	O
technical	O
bifascicular	B-Algorithm
block	I-Algorithm
,	O
since	O
the	O
block	O
occurs	O
above	O
the	O
bifurcation	O
of	O
the	O
left	O
anterior	O
and	O
left	O
posterior	O
fascicles	O
of	O
the	O
left	O
bundle	O
branch	O
.	O
</s>
<s>
Clinically	O
,	O
bifascicular	B-Algorithm
block	I-Algorithm
presents	O
with	O
one	O
of	O
two	O
ECG	B-Application
patterns	O
:	O
</s>
<s>
Right	B-Algorithm
bundle	I-Algorithm
branch	I-Algorithm
block	I-Algorithm
(	O
RBBB	B-Algorithm
)	O
with	O
left	O
anterior	O
fascicular	O
block	O
(	O
LAFB	O
)	O
,	O
manifested	O
as	O
left	O
axis	O
deviation	O
(	O
LAD	O
)	O
.	O
</s>
<s>
RBBB	B-Algorithm
and	O
left	B-Algorithm
posterior	I-Algorithm
fascicular	I-Algorithm
block	I-Algorithm
(	O
LPFB	B-Algorithm
)	O
,	O
manifested	O
as	O
right	O
axis	O
deviation	O
(	O
RAD	O
)	O
in	O
the	O
absence	O
of	O
other	O
causes	O
.	O
</s>
<s>
In	O
those	O
with	O
bifascicular	B-Algorithm
block	I-Algorithm
and	O
no	O
symptoms	O
,	O
little	O
with	O
respect	O
to	O
treatment	O
is	O
needed	O
.	O
</s>
<s>
In	O
those	O
with	O
syncope	O
,	O
a	O
pacemaker	B-Device
is	O
recommended	O
.	O
</s>
