<s>
Atrioventricular	B-Algorithm
reentrant	I-Algorithm
tachycardia	I-Algorithm
(	O
AVRT	B-Algorithm
)	O
,	O
or	O
atrioventricular	B-Algorithm
reciprocating	I-Algorithm
tachycardia	I-Algorithm
,	O
is	O
a	O
type	O
of	O
abnormal	B-Application
fast	B-Application
heart	I-Application
rhythm	I-Application
and	O
is	O
classified	O
as	O
a	O
type	O
of	O
supraventricular	B-Algorithm
tachycardia	I-Algorithm
(	O
SVT	O
)	O
.	O
</s>
<s>
AVRT	B-Algorithm
is	O
most	O
commonly	O
associated	O
with	O
Wolff	O
–	O
Parkinson	O
–	O
White	O
syndrome	O
,	O
but	O
is	O
also	O
seen	O
in	O
permanent	O
junctional	O
reentrant	O
tachycardia	B-Application
(	O
PJRT	B-Algorithm
)	O
.	O
</s>
<s>
In	O
AVRT	B-Algorithm
,	O
an	O
accessory	B-Algorithm
pathway	I-Algorithm
allows	O
electrical	O
signals	O
from	O
the	O
heart	O
's	O
ventricles	O
to	O
enter	O
the	O
atria	O
and	O
cause	O
earlier	O
than	O
normal	O
contraction	O
,	O
which	O
leads	O
to	O
repeated	O
stimulation	O
of	O
the	O
atrioventricular	B-Algorithm
node	O
.	O
</s>
<s>
An	O
episode	O
of	O
SVT	O
may	O
present	O
with	O
palpitations	B-Algorithm
,	O
dizziness	O
,	O
shortness	O
of	O
breath	O
,	O
or	O
losing	O
consciousness	O
(	O
fainting	O
)	O
.	O
</s>
<s>
The	O
electrocardiogram	B-Application
(	O
ECG	B-Application
)	O
would	O
appear	O
as	O
a	O
narrow-complex	O
SVT	O
.	O
</s>
<s>
Between	O
episodes	O
of	O
tachycardia	B-Application
the	O
affected	O
person	O
is	O
likely	O
to	O
be	O
asymptomatic	O
;	O
however	O
,	O
the	O
ECG	B-Application
would	O
demonstrate	O
the	O
classic	O
delta	O
wave	O
in	O
Wolff	O
–	O
Parkinson	O
–	O
White	O
syndrome	O
.	O
</s>
<s>
Two	O
distinct	O
pathways	O
are	O
involved	O
:	O
the	O
normal	O
atrioventricular	B-Algorithm
conduction	B-Algorithm
system	I-Algorithm
,	O
and	O
an	O
accessory	B-Algorithm
pathway	I-Algorithm
.	O
</s>
<s>
During	O
AVRT	B-Algorithm
,	O
the	O
electrical	O
signal	O
passes	O
in	O
the	O
normal	O
manner	O
from	O
the	O
AV	O
node	O
into	O
the	O
ventricles	O
.	O
</s>
<s>
Then	O
,	O
the	O
electrical	O
impulse	O
pathologically	O
passes	O
back	O
into	O
the	O
atria	O
via	O
the	O
accessory	B-Algorithm
pathway	I-Algorithm
,	O
causing	O
atrial	O
contraction	O
,	O
and	O
returns	O
to	O
the	O
AV	O
node	O
to	O
complete	O
the	O
reentrant	O
circuit	O
(	O
see	O
figure	O
)	O
.	O
</s>
<s>
Initiation	O
of	O
AVRT	B-Algorithm
may	O
be	O
through	O
a	O
premature	B-Algorithm
impulse	I-Algorithm
of	O
atrial	O
,	O
junctional	O
,	O
or	O
ventricular	O
origin	O
.	O
</s>
<s>
Long-term	O
management	O
includes	O
beta	O
blocker	O
therapy	O
and	O
radiofrequency	O
ablation	O
of	O
the	O
accessory	B-Algorithm
pathway	I-Algorithm
.	O
</s>
