<s>
Atrial	B-Application
fibrillation	I-Application
(	O
AF	O
or	O
A-fib	B-Application
)	O
is	O
an	O
abnormal	B-Application
heart	I-Application
rhythm	I-Application
(	O
arrhythmia	B-Application
)	O
characterized	O
by	O
rapid	B-Application
and	I-Application
irregular	I-Application
beating	I-Application
of	O
the	O
atrial	O
chambers	O
of	O
the	O
heart	O
.	O
</s>
<s>
It	O
may	O
also	O
start	O
as	O
other	O
forms	O
of	O
arrhythmia	B-Application
such	O
as	O
atrial	O
flutter	O
that	O
then	O
transform	O
into	O
AF	O
.	O
</s>
<s>
Symptomatic	O
episodes	O
may	O
involve	O
heart	B-Algorithm
palpitations	I-Algorithm
,	O
fainting	O
,	O
lightheadedness	O
,	O
shortness	O
of	O
breath	O
,	O
or	O
chest	O
pain	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
is	O
associated	O
with	O
an	O
increased	O
risk	O
of	O
heart	O
failure	O
,	O
dementia	O
,	O
and	O
stroke	O
.	O
</s>
<s>
It	O
is	O
a	O
type	O
of	O
supraventricular	B-Algorithm
tachycardia	I-Algorithm
.	O
</s>
<s>
Healthcare	O
professionals	O
might	O
suspect	O
AF	O
after	O
feeling	O
the	O
pulse	O
and	O
confirm	O
the	O
diagnosis	O
by	O
interpreting	O
an	O
electrocardiogram	B-Application
(	O
ECG	B-Application
)	O
.	O
</s>
<s>
A	O
typical	O
ECG	B-Application
in	O
AF	O
shows	O
irregularly	O
spaced	O
QRS	B-Algorithm
complexes	I-Algorithm
without	O
P	B-Algorithm
waves	I-Algorithm
.	O
</s>
<s>
Electrical	B-Application
cardioversion	O
can	O
convert	O
AF	O
to	O
normal	O
heart	B-Algorithm
rhythm	I-Algorithm
and	O
is	O
often	O
necessary	O
for	O
emergency	O
use	O
if	O
the	O
person	O
is	O
unstable	O
.	O
</s>
<s>
Ablation	B-Algorithm
may	O
prevent	O
recurrence	O
in	O
some	O
people	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
is	O
the	O
most	O
common	O
serious	O
abnormal	B-Application
heart	I-Application
rhythm	I-Application
and	O
,	O
as	O
of	O
2020	O
,	O
affects	O
more	O
than	O
33	O
million	O
people	O
worldwide	O
.	O
</s>
<s>
A-fib	B-Application
and	O
atrial	O
flutter	O
resulted	O
in	O
193,300	O
deaths	O
in	O
2015	O
,	O
up	O
from	O
29,000	O
in	O
1990	O
.	O
</s>
<s>
Thomas	O
Lewis	O
was	O
the	O
first	O
doctor	O
to	O
document	O
this	O
by	O
ECG	B-Application
in	O
1909	O
.	O
</s>
<s>
AF	O
is	O
usually	O
accompanied	O
by	O
symptoms	O
related	O
to	O
a	O
rapid	B-Application
heart	I-Application
rate	I-Application
.	O
</s>
<s>
Rapid	O
and	O
irregular	B-Application
heart	I-Application
rates	I-Application
may	O
be	O
perceived	O
as	O
the	O
sensation	O
of	O
the	O
heart	O
beating	O
too	O
fast	O
,	O
irregularly	O
,	O
or	O
skipping	O
beats	O
(	O
palpitations	B-Algorithm
)	O
or	O
exercise	O
intolerance	O
and	O
occasionally	O
may	O
produce	O
anginal	O
chest	O
pain	O
(	O
if	O
the	O
high	B-Application
heart	I-Application
rate	I-Application
causes	O
the	O
heart	O
's	O
demand	O
for	O
oxygen	O
to	O
increase	O
beyond	O
the	O
supply	O
of	O
available	O
oxygen	O
)	O
.	O
</s>
<s>
The	O
abnormal	B-Application
heart	I-Application
rhythm	I-Application
(	O
arrhythmia	B-Application
)	O
is	O
sometimes	O
only	O
identified	O
with	O
the	O
onset	O
of	O
a	O
stroke	O
or	O
a	O
transient	O
ischemic	O
attack	O
(	O
TIA	O
)	O
.	O
</s>
<s>
It	O
is	O
not	O
uncommon	O
for	O
a	O
person	O
to	O
first	O
become	O
aware	O
of	O
AF	O
from	O
a	O
routine	O
physical	O
examination	O
or	O
electrocardiogram	B-Application
,	O
as	O
it	O
often	O
does	O
not	O
cause	O
symptoms	O
.	O
</s>
<s>
Presentation	O
is	O
similar	O
to	O
other	O
forms	O
of	O
rapid	B-Application
heart	I-Application
rate	I-Application
and	O
may	O
be	O
asymptomatic	O
.	O
</s>
<s>
Palpitations	B-Algorithm
and	O
chest	O
discomfort	O
are	O
common	O
complaints	O
.	O
</s>
<s>
Common	O
symptoms	O
of	O
uncontrolled	O
atrial	B-Application
fibrillation	I-Application
may	O
include	O
shortness	O
of	O
breath	O
,	O
shortness	O
of	O
breath	O
when	O
lying	O
flat	O
,	O
dizziness	O
,	O
and	O
sudden	O
onset	O
of	O
shortness	O
of	O
breath	O
during	O
the	O
night	O
.	O
</s>
<s>
By	O
definition	O
,	O
the	O
heart	O
rate	O
will	O
be	O
greater	B-Application
than	I-Application
100	I-Application
beats	I-Application
per	I-Application
minute	I-Application
.	O
</s>
<s>
Many	O
of	O
the	O
symptoms	O
associated	O
with	O
uncontrolled	O
atrial	B-Application
fibrillation	I-Application
are	O
a	O
manifestation	O
of	O
congestive	O
heart	O
failure	O
due	O
to	O
the	O
reduced	O
cardiac	O
output	O
.	O
</s>
<s>
Congenital	O
heart	O
disease	O
is	O
a	O
strong	O
risk	O
factor	O
for	O
developing	O
atrial	B-Application
fibrillation	I-Application
—	O
a	O
20-year-old	O
adult	O
with	O
congenital	O
heart	O
disease	O
has	O
a	O
comparable	O
lifetime	O
risk	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
when	O
compared	O
to	O
a	O
55-year-old	O
adult	O
with	O
no	O
history	O
of	O
congenital	O
heart	O
disease	O
.	O
</s>
<s>
People	O
with	O
congenital	O
heart	O
disease	O
tend	O
to	O
develop	O
atrial	B-Application
fibrillation	I-Application
at	O
a	O
younger	O
age	O
,	O
that	O
is	O
more	O
likely	O
to	O
be	O
of	O
right	O
atrial	O
origin	O
(	O
atypical	O
)	O
than	O
of	O
left	O
origin	O
,	O
and	O
have	O
a	O
greater	O
risk	O
of	O
progressing	O
to	O
permanent	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Sepsis	O
also	O
increases	O
the	O
risk	O
of	O
developing	O
new-onset	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Caffeine	B-Application
consumption	O
does	O
not	O
appear	O
to	O
be	O
associated	O
with	O
AF	O
;	O
excessive	O
alcohol	O
consumption	O
(	O
"	O
binge	O
drinking	O
"	O
or	O
"	O
holiday	O
heart	O
syndrome	O
"	O
)	O
is	O
linked	O
to	O
AF	O
.	O
</s>
<s>
Low-to-moderate	O
alcohol	O
consumption	O
also	O
appears	O
to	O
be	O
associated	O
with	O
an	O
increased	O
risk	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
,	O
although	O
the	O
increase	O
in	O
risk	O
associated	O
with	O
drinking	O
less	O
than	O
two	O
drinks	O
daily	O
appears	O
to	O
be	O
small	O
.	O
</s>
<s>
Tobacco	O
smoking	O
and	O
secondhand	O
tobacco	O
smoke	O
exposure	O
are	O
associated	O
with	O
an	O
increased	O
risk	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Long-term	O
endurance	O
exercise	O
that	O
far	O
exceeds	O
the	O
recommended	O
amount	O
of	O
exercise	O
(	O
e.g.	O
,	O
long-distance	O
cycling	O
or	O
marathon	B-Application
running	O
)	O
appears	O
to	O
be	O
associated	O
with	O
a	O
modest	O
increase	O
in	O
the	O
risk	O
of	O
atrial	B-Application
fibrillation	I-Application
in	O
middle-aged	O
and	O
elderly	O
people	O
.	O
</s>
<s>
Four	O
types	O
of	O
genetic	O
disorder	O
are	O
associated	O
with	O
atrial	B-Application
fibrillation	I-Application
:	O
</s>
<s>
All	O
of	O
these	O
mutations	O
affect	O
the	O
processes	O
of	O
polarization-depolarization	O
of	O
the	O
myocardium	O
,	O
cellular	O
hyper-excitability	O
,	O
shortening	O
of	O
effective	B-Algorithm
refractory	I-Algorithm
period	I-Algorithm
favoring	O
re-entries	O
.	O
</s>
<s>
Other	O
mutations	O
in	O
genes	O
,	O
such	O
as	O
GJA5	O
,	O
affect	O
gap	O
junctions	O
,	O
generating	O
a	O
cellular	O
uncoupling	O
that	O
promotes	O
re-entries	O
and	O
a	O
slow	O
conduction	B-Algorithm
velocity	O
.	O
</s>
<s>
In	O
these	O
loci	O
there	O
are	O
SNPs	O
associated	O
with	O
a	O
30%	O
increase	O
in	O
risk	O
of	O
recurrent	O
atrial	O
tachycardia	B-Application
after	O
ablation	B-Algorithm
.	O
</s>
<s>
They	O
are	O
associated	O
with	O
genes	O
that	O
encode	O
transcription	O
factors	O
,	O
such	O
as	O
TBX3	O
and	O
TBX5	O
,	O
NKX2-5	O
or	O
PITX2	O
,	O
involved	O
in	O
the	O
regulation	O
of	O
cardiac	O
conduction	B-Algorithm
,	O
modulation	O
of	O
ion	O
channels	O
and	O
in	O
cardiac	O
development	O
.	O
</s>
<s>
Have	O
been	O
also	O
identified	O
new	O
genes	O
involved	O
in	O
tachycardia	B-Application
(	O
CASQ2	O
)	O
or	O
associated	O
with	O
an	O
alteration	O
in	O
cardiomyocyte	O
communication	O
(	O
PKP2	O
)	O
.	O
</s>
<s>
It	O
is	O
due	O
to	O
a	O
remodeling	O
of	O
cardiac	O
tissue	O
,	O
and	O
an	O
increase	O
in	O
vagal	O
tone	O
,	O
which	O
shortens	O
the	O
effective	B-Algorithm
refractory	I-Algorithm
period	I-Algorithm
(	O
ERP	O
)	O
favoring	O
re-entries	O
from	O
the	O
pulmonary	O
veins	O
.	O
</s>
<s>
Acute	O
alcohol	O
consumption	O
can	O
directly	O
trigger	O
an	O
episode	O
of	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Regular	O
alcohol	O
consumption	O
also	O
increases	O
the	O
risk	O
of	O
atrial	B-Application
fibrillation	I-Application
in	O
several	O
ways	O
.	O
</s>
<s>
The	O
long-term	O
use	O
of	O
alcohol	O
alters	O
the	O
physical	O
structure	O
and	O
electrical	B-Application
properties	O
of	O
the	O
atria	O
.	O
</s>
<s>
The	O
aforementioned	O
structural	O
changes	O
increase	O
the	O
risk	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
when	O
paired	O
with	O
the	O
harmful	O
changes	O
in	O
how	O
the	O
left	O
atrium	O
conducts	O
electricity	O
.	O
</s>
<s>
All	O
atrial	O
remodeling	O
is	O
related	O
to	O
heterogeneous	O
conduction	B-Algorithm
and	O
the	O
formation	O
of	O
re-entrant	O
electric	O
conduction	B-Algorithm
from	O
the	O
pulmonary	O
veins	O
.	O
</s>
<s>
Several	O
medications	O
are	O
associated	O
with	O
an	O
increased	O
risk	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Few	O
studies	O
have	O
examined	O
this	O
phenomenon	O
,	O
and	O
the	O
exact	O
incidence	O
of	O
medication-induced	O
atrial	B-Application
fibrillation	I-Application
is	O
unknown	O
.	O
</s>
<s>
Medications	O
that	O
are	O
commonly	O
associated	O
with	O
an	O
increased	O
risk	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
include	O
dobutamine	O
and	O
the	O
chemotherapy	O
agent	O
cisplatin	O
.	O
</s>
<s>
Other	O
medications	O
that	O
rarely	O
increase	O
the	O
risk	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
include	O
adenosine	O
,	O
aminophylline	O
,	O
corticosteroids	O
,	O
ivabradine	O
,	O
ondansetron	O
,	O
and	O
antipsychotics	O
.	O
</s>
<s>
This	O
form	O
of	O
atrial	B-Application
fibrillation	I-Application
occurs	O
in	O
people	O
of	O
all	O
ages	O
but	O
is	O
most	O
common	O
in	O
the	O
elderly	O
,	O
in	O
those	O
with	O
other	O
atrial	B-Application
fibrillation	I-Application
risk	O
factors	O
,	O
and	O
after	O
heart	O
surgery	O
.	O
</s>
<s>
The	O
normal	O
electrical	B-Algorithm
conduction	I-Algorithm
system	I-Algorithm
of	I-Algorithm
the	I-Algorithm
heart	I-Algorithm
allows	O
electrical	B-Application
impulses	O
generated	O
by	O
the	O
heart	O
's	O
own	O
pacemaker	O
(	O
the	O
sinoatrial	O
node	O
)	O
to	O
spread	O
to	O
and	O
stimulate	O
the	O
muscular	O
layer	O
of	O
the	O
heart	O
(	O
myocardium	O
)	O
in	O
both	O
the	O
atria	O
and	O
the	O
ventricles	O
.	O
</s>
<s>
In	O
AF	O
,	O
the	O
normal	O
regular	O
electrical	B-Application
impulses	O
generated	O
by	O
the	O
sinoatrial	O
node	O
are	O
overwhelmed	O
by	O
disorganized	O
electrical	B-Application
waves	O
,	O
usually	O
originating	O
from	O
the	O
roots	O
of	O
the	O
pulmonary	O
veins	O
.	O
</s>
<s>
These	O
disorganized	O
waves	O
conduct	O
intermittently	O
through	O
the	O
atrioventricular	B-Algorithm
node	O
,	O
leading	O
to	O
irregular	O
activation	O
of	O
the	O
ventricles	O
that	O
generate	O
the	O
heartbeat	O
.	O
</s>
<s>
The	O
primary	O
pathologic	O
change	O
seen	O
in	O
atrial	B-Application
fibrillation	I-Application
is	O
the	O
progressive	O
fibrosis	O
of	O
the	O
atria	O
.	O
</s>
<s>
Mutation	O
of	O
the	O
lamin	O
AC	O
gene	O
is	O
also	O
associated	O
with	O
fibrosis	O
of	O
the	O
atria	O
that	O
can	O
lead	O
to	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
This	O
process	O
occurs	O
gradually	O
,	O
and	O
experimental	O
studies	O
have	O
revealed	O
patchy	O
atrial	O
fibrosis	O
may	O
precede	O
the	O
occurrence	O
of	O
atrial	B-Application
fibrillation	I-Application
and	O
may	O
progress	O
with	O
prolonged	O
durations	O
of	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Fibrosis	O
is	O
not	O
limited	O
to	O
the	O
muscle	O
mass	O
of	O
the	O
atria	O
and	O
may	O
occur	O
in	O
the	O
sinus	O
node	O
(	O
SA	O
node	O
)	O
and	O
atrioventricular	B-Algorithm
node	O
(	O
AV	O
node	O
)	O
,	O
correlating	O
with	O
sick	B-Algorithm
sinus	I-Algorithm
syndrome	I-Algorithm
.	O
</s>
<s>
Prolonged	O
episodes	O
of	O
atrial	B-Application
fibrillation	I-Application
have	O
been	O
shown	O
to	O
correlate	O
with	O
prolongation	O
of	O
the	O
sinus	O
node	O
recovery	O
time	O
;	O
this	O
suggests	O
that	O
dysfunction	O
of	O
the	O
SA	O
node	O
is	O
progressive	O
with	O
prolonged	O
episodes	O
of	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Along	O
with	O
fibrosis	O
,	O
alterations	O
in	O
the	O
atria	O
that	O
predispose	O
to	O
atrial	B-Application
fibrillation	I-Application
affect	O
their	O
electrical	B-Application
properties	O
,	O
as	O
well	O
as	O
their	O
responsiveness	O
to	O
the	O
autonomic	O
nervous	O
system	O
.	O
</s>
<s>
There	O
are	O
multiple	O
theories	O
about	O
the	O
cause	O
of	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
An	O
important	O
theory	O
is	O
that	O
the	O
regular	O
impulses	O
produced	O
by	O
the	O
sinus	O
node	O
for	O
a	O
normal	O
heartbeat	O
are	O
overwhelmed	O
by	O
rapid	O
electrical	B-Application
discharges	O
produced	O
in	O
the	O
atria	O
and	O
adjacent	O
parts	O
of	O
the	O
pulmonary	O
veins	O
.	O
</s>
<s>
Sources	O
of	O
these	O
disturbances	O
are	O
either	O
automatic	O
foci	O
,	O
often	O
localized	O
at	O
one	O
of	O
the	O
pulmonary	O
veins	O
,	O
or	O
a	O
small	O
number	O
of	O
localized	O
sources	O
in	O
the	O
form	O
of	O
either	O
a	O
re-entrant	O
leading	O
circle	O
or	O
electrical	B-Application
spiral	O
waves	O
(	O
rotors	O
)	O
;	O
these	O
localized	O
sources	O
may	O
be	O
in	O
the	O
left	O
atrium	O
near	O
the	O
pulmonary	O
veins	O
or	O
in	O
a	O
variety	O
of	O
other	O
locations	O
through	O
both	O
the	O
left	O
or	O
right	O
atrium	O
.	O
</s>
<s>
Three	O
fundamental	O
components	O
favor	O
the	O
establishment	O
of	O
a	O
leading	O
circle	O
or	O
a	O
rotor	O
:	O
slow	O
conduction	B-Algorithm
velocity	O
of	O
the	O
cardiac	B-Algorithm
action	I-Algorithm
potential	I-Algorithm
,	O
a	O
short	O
refractory	O
period	O
,	O
and	O
a	O
small	O
wavelength	O
.	O
</s>
<s>
If	O
the	O
action	O
potential	O
has	O
fast	O
conduction	B-Algorithm
,	O
with	O
a	O
long	O
refractory	O
period	O
and/or	O
conduction	B-Algorithm
pathway	I-Algorithm
shorter	O
than	O
the	O
wavelength	O
,	O
an	O
AF	O
focus	O
would	O
not	O
be	O
established	O
.	O
</s>
<s>
This	O
reduces	O
the	O
duration	O
of	O
action	O
potential	O
and	O
the	O
refractory	O
period	O
,	O
thus	O
favoring	O
the	O
conduction	B-Algorithm
of	O
re-entrant	O
waves	O
.	O
</s>
<s>
The	O
abnormal	O
distribution	O
of	O
gap	O
junction	O
proteins	O
such	O
as	O
GJA1	O
(	O
also	O
known	O
as	O
Connexin	O
43	O
)	O
,	O
and	O
GJA5	O
(	O
Connexin	O
40	O
)	O
causes	O
non-uniformity	O
of	O
electrical	B-Application
conduction	B-Algorithm
,	O
thus	O
causing	O
the	O
arrhythmia	B-Application
.	O
</s>
<s>
AF	O
can	O
be	O
distinguished	O
from	O
atrial	O
flutter	O
(	O
AFL	O
)	O
,	O
which	O
appears	O
as	O
an	O
organized	O
electrical	B-Application
circuit	O
usually	O
in	O
the	O
right	O
atrium	O
.	O
</s>
<s>
AFL	O
produces	O
characteristic	O
saw-toothed	O
F-waves	O
of	O
constant	O
amplitude	O
and	O
frequency	O
on	O
an	O
ECG	B-Application
,	O
whereas	O
AF	O
does	O
not	O
.	O
</s>
<s>
Although	O
AF	O
and	O
atrial	O
flutter	O
are	O
distinct	O
arrhythmias	B-Application
,	O
atrial	O
flutter	O
may	O
degenerate	O
into	O
AF	O
,	O
and	O
an	O
individual	O
may	O
experience	O
both	O
arrhythmias	B-Application
at	O
different	O
times	O
.	O
</s>
<s>
Although	O
the	O
electrical	B-Application
impulses	O
of	O
AF	O
occur	O
at	O
a	O
high	O
rate	O
,	O
most	O
of	O
them	O
do	O
not	O
result	O
in	O
a	O
heartbeat	O
.	O
</s>
<s>
A	O
heartbeat	O
results	O
when	O
an	O
electrical	B-Application
impulse	O
from	O
the	O
atria	O
passes	O
through	O
the	O
atrioventricular	B-Algorithm
(	O
AV	O
)	O
node	O
to	O
the	O
ventricles	O
and	O
causes	O
them	O
to	O
contract	O
.	O
</s>
<s>
During	O
AF	O
,	O
if	O
all	O
of	O
the	O
impulses	O
from	O
the	O
atria	O
passed	O
through	O
the	O
AV	O
node	O
,	O
there	O
would	O
be	O
severe	O
ventricular	B-Application
tachycardia	I-Application
,	O
resulting	O
in	O
a	O
severe	O
reduction	O
of	O
cardiac	O
output	O
.	O
</s>
<s>
This	O
dangerous	O
situation	O
is	O
prevented	O
by	O
the	O
AV	O
node	O
since	O
its	O
limited	O
conduction	B-Algorithm
velocity	O
reduces	O
the	O
rate	O
at	O
which	O
impulses	O
reach	O
the	O
ventricles	O
during	O
AF	O
.	O
</s>
<s>
The	O
evaluation	O
of	O
atrial	B-Application
fibrillation	I-Application
involves	O
a	O
determination	O
of	O
the	O
cause	O
of	O
the	O
arrhythmia	B-Application
,	O
and	O
classification	O
of	O
the	O
arrhythmia	B-Application
.	O
</s>
<s>
Diagnostic	O
investigation	O
of	O
AF	O
typically	O
includes	O
a	O
complete	O
history	O
and	O
physical	O
examination	O
,	O
ECG	B-Application
,	O
transthoracic	B-Algorithm
echocardiogram	I-Algorithm
,	O
complete	O
blood	O
count	O
,	O
and	O
serum	O
thyroid	O
stimulating	O
hormone	O
level	O
.	O
</s>
<s>
Numerous	O
guidelines	O
recommend	O
opportunistic	O
screening	O
for	O
atrial	B-Application
fibrillation	I-Application
in	O
those	O
65	O
years	O
and	O
older	O
.	O
</s>
<s>
•	O
European	O
Heart	B-Algorithm
Rhythm	I-Algorithm
Society	O
,	O
</s>
<s>
A	O
Scottish	O
inquiry	O
into	O
atrial	B-Application
fibrillation	I-Application
estimated	O
that	O
as	O
many	O
as	O
one-third	O
of	O
people	O
with	O
AF	O
are	O
undiagnosed	O
.	O
</s>
<s>
In	O
general	O
,	O
the	O
minimal	O
evaluation	O
of	O
atrial	B-Application
fibrillation	I-Application
should	O
be	O
performed	O
in	O
all	O
individuals	O
with	O
AF	O
.	O
</s>
<s>
The	O
history	O
of	O
the	O
individual	O
's	O
atrial	B-Application
fibrillation	I-Application
episodes	O
is	O
probably	O
the	O
most	O
important	O
part	O
of	O
the	O
evaluation	O
.	O
</s>
<s>
Distinctions	O
should	O
be	O
made	O
between	O
those	O
who	O
are	O
entirely	O
asymptomatic	O
when	O
they	O
are	O
in	O
AF	O
(	O
in	O
which	O
case	O
the	O
AF	O
is	O
found	O
as	O
an	O
incidental	O
finding	O
on	O
an	O
ECG	B-Application
or	O
physical	O
examination	O
)	O
and	O
those	O
who	O
have	O
gross	O
and	O
obvious	O
symptoms	O
due	O
to	O
AF	O
and	O
can	O
pinpoint	O
whenever	O
they	O
go	O
into	O
AF	O
or	O
revert	O
to	O
sinus	O
rhythm	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
is	O
diagnosed	O
on	O
an	O
electrocardiogram	B-Application
(	O
ECG	B-Application
)	O
,	O
an	O
investigation	O
performed	O
routinely	O
whenever	O
an	O
irregular	B-Application
heartbeat	I-Application
is	O
suspected	O
.	O
</s>
<s>
Characteristic	O
findings	O
are	O
the	O
absence	O
of	O
P	B-Algorithm
waves	I-Algorithm
,	O
with	O
disorganized	O
electrical	B-Application
activity	O
in	O
their	O
place	O
,	O
and	O
irregular	O
R	O
–	O
R	O
intervals	O
due	O
to	O
irregular	O
conduction	B-Algorithm
of	O
impulses	O
to	O
the	O
ventricles	O
.	O
</s>
<s>
At	O
very	O
fast	B-Application
heart	I-Application
rates	I-Application
,	O
atrial	B-Application
fibrillation	I-Application
may	O
look	O
more	O
regular	O
,	O
which	O
may	O
make	O
it	O
more	O
difficult	O
to	O
separate	O
from	O
other	O
supraventricular	B-Algorithm
tachycardias	I-Algorithm
or	O
ventricular	B-Application
tachycardia	I-Application
.	O
</s>
<s>
QRS	B-Algorithm
complexes	I-Algorithm
should	O
be	O
narrow	O
,	O
signifying	O
that	O
they	O
are	O
initiated	O
by	O
normal	O
conduction	B-Algorithm
of	O
atrial	O
electrical	B-Application
activity	O
through	O
the	O
intraventricular	B-Algorithm
conduction	I-Algorithm
system	I-Algorithm
.	O
</s>
<s>
Wide	O
QRS	B-Algorithm
complexes	I-Algorithm
are	O
worrisome	O
for	O
ventricular	B-Application
tachycardia	I-Application
,	O
although	O
,	O
in	O
cases	O
where	O
there	O
is	O
a	O
disease	O
of	O
the	O
conduction	B-Algorithm
system	I-Algorithm
,	O
wide	O
complexes	O
may	O
be	O
present	O
in	O
A-fib	B-Application
with	O
a	O
rapid	O
ventricular	O
response	O
.	O
</s>
<s>
If	O
paroxysmal	O
AF	O
is	O
suspected	O
,	O
but	O
an	O
ECG	B-Application
during	O
an	O
office	O
visit	O
shows	O
only	O
a	O
regular	O
rhythm	O
,	O
AF	O
episodes	O
may	O
be	O
detected	O
and	O
documented	O
with	O
the	O
use	O
of	O
ambulatory	O
Holter	O
monitoring	O
(	O
e.g.	O
,	O
for	O
a	O
day	O
)	O
.	O
</s>
<s>
In	O
general	O
,	O
a	O
non-invasive	O
transthoracic	B-Algorithm
echocardiogram	I-Algorithm
(	O
TTE	O
)	O
is	O
performed	O
in	O
newly	O
diagnosed	O
AF	O
,	O
as	O
well	O
as	O
if	O
there	O
is	O
a	O
major	O
change	O
in	O
the	O
person	O
's	O
clinical	O
state	O
.	O
</s>
<s>
Significant	O
enlargement	O
of	O
both	O
the	O
left	O
and	O
right	O
atria	O
is	O
associated	O
with	O
long-standing	O
atrial	B-Application
fibrillation	I-Application
and	O
,	O
if	O
noted	O
at	O
the	O
initial	O
presentation	O
of	O
atrial	B-Application
fibrillation	I-Application
,	O
suggests	O
that	O
the	O
atrial	B-Application
fibrillation	I-Application
is	O
likely	O
to	O
be	O
of	O
a	O
longer	O
duration	O
than	O
the	O
individual	O
's	O
symptoms	O
.	O
</s>
<s>
In	O
general	O
,	O
an	O
extended	O
evaluation	O
is	O
not	O
necessary	O
for	O
most	O
individuals	O
with	O
atrial	B-Application
fibrillation	I-Application
and	O
is	O
performed	O
only	O
if	O
abnormalities	O
are	O
noted	O
in	O
the	O
limited	O
evaluation	O
,	O
if	O
a	O
reversible	O
cause	O
of	O
the	O
atrial	B-Application
fibrillation	I-Application
is	O
suggested	O
,	O
or	O
if	O
further	O
evaluation	O
may	O
change	O
the	O
treatment	O
course	O
.	O
</s>
<s>
In	O
general	O
,	O
a	O
chest	O
X-ray	O
is	O
performed	O
only	O
if	O
a	O
pulmonary	O
cause	O
of	O
atrial	B-Application
fibrillation	I-Application
is	O
suggested	O
,	O
or	O
if	O
other	O
cardiac	O
conditions	O
are	O
suspected	O
(	O
in	O
particular	O
congestive	O
heart	O
failure	O
)	O
.	O
</s>
<s>
In	O
particular	O
,	O
if	O
underlying	O
pneumonia	O
is	O
suggested	O
,	O
then	O
treatment	O
of	O
the	O
pneumonia	O
may	O
cause	O
the	O
atrial	B-Application
fibrillation	I-Application
to	O
terminate	O
on	O
its	O
own	O
.	O
</s>
<s>
A	O
regular	O
echocardiogram	B-Application
(	O
transthoracic	B-Algorithm
echo/TTE	I-Algorithm
)	O
has	O
a	O
low	O
sensitivity	O
for	O
identifying	O
blood	O
clots	O
in	O
the	O
heart	O
.	O
</s>
<s>
If	O
this	O
is	O
suspected	O
(	O
e.g.	O
,	O
when	O
planning	O
urgent	O
electrical	B-Application
cardioversion	O
)	O
,	O
a	O
transesophageal	B-Algorithm
echocardiogram/TEE	I-Algorithm
(	O
or	O
TOE	O
where	O
British	O
spelling	O
is	O
used	O
)	O
is	O
preferred	O
.	O
</s>
<s>
The	O
TEE	O
has	O
much	O
better	O
visualization	O
of	O
the	O
left	O
atrial	O
appendage	O
than	O
transthoracic	B-Application
echocardiography	I-Application
.	O
</s>
<s>
This	O
structure	O
,	O
located	O
in	O
the	O
left	O
atrium	O
,	O
is	O
the	O
place	O
where	O
a	O
blood	O
clot	O
forms	O
in	O
more	O
than	O
90%	O
of	O
cases	O
in	O
non-valvular	O
(	O
or	O
non-rheumatic	O
)	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
A	O
Holter	O
monitor	O
is	O
a	O
wearable	O
ambulatory	O
heart	O
monitor	O
that	O
continuously	O
monitors	O
the	O
heart	O
rate	O
and	O
heart	B-Algorithm
rhythm	I-Algorithm
for	O
a	O
short	O
duration	O
,	O
typically	O
24	O
hours	O
.	O
</s>
<s>
In	O
individuals	O
with	O
symptoms	O
of	O
significant	O
shortness	O
of	O
breath	O
with	O
exertion	O
or	O
palpitations	B-Algorithm
regularly	O
,	O
a	O
Holter	O
monitor	O
may	O
be	O
of	O
benefit	O
to	O
determine	O
whether	O
rapid	B-Application
heart	I-Application
rates	I-Application
(	O
or	O
unusually	O
slow	O
heart	O
rates	O
)	O
during	O
atrial	B-Application
fibrillation	I-Application
are	O
the	O
cause	O
of	O
the	O
symptoms	O
.	O
</s>
<s>
Some	O
individuals	O
with	O
atrial	B-Application
fibrillation	I-Application
do	O
well	O
with	O
normal	O
activity	O
but	O
develop	O
shortness	O
of	O
breath	O
with	O
exertion	O
.	O
</s>
<s>
It	O
may	O
be	O
unclear	O
whether	O
the	O
shortness	O
of	O
breath	O
is	O
due	O
to	O
a	O
blunted	O
heart	O
rate	O
response	O
to	O
exertion	O
caused	O
by	O
excessive	O
atrioventricular	B-Algorithm
node-blocking	O
agents	O
,	O
a	O
very	O
rapid	B-Application
heart	I-Application
rate	I-Application
during	O
exertion	O
,	O
or	O
other	O
underlying	O
conditions	O
such	O
as	O
chronic	O
lung	O
disease	O
or	O
coronary	O
ischemia	O
.	O
</s>
<s>
Valvular	O
AF	O
refers	O
to	O
AF	O
attributable	O
to	O
moderate	O
to	O
severe	O
mitral	O
valve	O
stenosis	O
or	O
atrial	B-Application
fibrillation	I-Application
in	O
the	O
presence	O
of	O
a	O
mechanical	O
artificial	O
heart	O
valve	O
.	O
</s>
<s>
Prevention	O
of	O
atrial	B-Application
fibrillation	I-Application
focuses	O
primarily	O
on	O
preventing	O
or	O
controlling	O
its	O
risk	O
factors	O
.	O
</s>
<s>
Several	O
healthy	O
lifestyle	O
behaviors	O
are	O
associated	O
with	O
a	O
lower	O
likelihood	O
of	O
developing	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Consistent	O
moderate-intensity	O
aerobic	O
exercise	O
,	O
defined	O
as	O
achieving	O
3.0-5.9	O
METs	O
of	O
intensity	O
,	O
for	O
at	O
least	O
150	O
minutes	O
per	O
week	O
may	O
reduce	O
the	O
risk	O
of	O
developing	O
new-onset	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Few	O
studies	O
have	O
examined	O
the	O
role	O
of	O
specific	O
dietary	O
changes	O
and	O
how	O
it	O
relates	O
to	O
the	O
prevention	O
of	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
If	O
cardiovascularly	O
unstable	O
due	O
to	O
uncontrolled	O
tachycardia	B-Application
,	O
immediate	O
cardioversion	O
is	O
indicated	O
.	O
</s>
<s>
Many	O
antiarrhythmics	B-Algorithm
,	O
when	O
used	O
long	O
term	O
,	O
increase	O
the	O
risk	O
of	O
death	O
without	O
any	O
meaningful	O
benefit	O
.	O
</s>
<s>
An	O
integrated	O
management	O
approach	O
,	O
which	O
includes	O
stroke	O
prevention	O
,	O
symptoms	O
control	O
and	O
management	O
of	O
associated	O
comorbidities	O
was	O
associated	O
with	O
better	O
outcomes	O
in	O
patients	O
with	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Regular	O
aerobic	O
exercise	O
improves	O
atrial	B-Application
fibrillation	I-Application
symptoms	O
and	O
AF-related	O
quality	O
of	O
life	O
.	O
</s>
<s>
The	O
effect	O
of	O
high-intensity	O
interval	O
training	O
on	O
reducing	O
atrial	B-Application
fibrillation	I-Application
burden	O
is	O
unclear	O
.	O
</s>
<s>
Weight	O
loss	O
of	O
at	O
least	O
10%	O
is	O
associated	O
with	O
reduced	O
atrial	B-Application
fibrillation	I-Application
burden	O
in	O
people	O
who	O
are	O
overweight	O
or	O
obese	O
.	O
</s>
<s>
For	O
people	O
who	O
have	O
both	O
atrial	B-Application
fibrillation	I-Application
and	O
obstructive	O
sleep	O
apnea	O
,	O
observational	O
studies	O
suggest	O
that	O
continuous	O
positive	O
airway	O
pressure	O
(	O
CPAP	O
)	O
treatment	O
appears	O
to	O
lower	O
the	O
risk	O
of	O
atrial	B-Application
fibrillation	I-Application
recurrence	O
after	O
undergoing	O
ablation	B-Algorithm
.	O
</s>
<s>
Randomized	O
controlled	O
trials	O
examining	O
the	O
role	O
of	O
obstructive	O
sleep	O
apnea	O
treatment	O
on	O
atrial	B-Application
fibrillation	I-Application
incidence	O
and	O
burden	O
are	O
lacking	O
.	O
</s>
<s>
Guideline-recommended	O
lifestyle	O
and	O
medical	O
interventions	O
are	O
recommended	O
for	O
people	O
with	O
atrial	B-Application
fibrillation	I-Application
and	O
coexisting	O
conditions	O
such	O
as	O
hyperlipidemia	O
,	O
diabetes	O
mellitus	O
,	O
or	O
hypertension	O
without	O
specific	O
blood	O
sugar	O
or	O
blood	O
pressure	O
targets	O
for	O
people	O
with	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Bariatric	O
surgery	O
may	O
reduce	O
the	O
risk	O
of	O
new-onset	O
atrial	B-Application
fibrillation	I-Application
in	O
people	O
with	O
obesity	O
without	O
AF	O
and	O
may	O
reduce	O
the	O
risk	O
of	O
a	O
recurrence	O
of	O
AF	O
after	O
an	O
ablation	B-Algorithm
procedure	O
in	O
people	O
with	O
coexisting	O
obesity	O
and	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
It	O
is	O
important	O
for	O
all	O
people	O
with	O
atrial	B-Application
fibrillation	I-Application
to	O
optimize	O
the	O
control	O
of	O
all	O
coexisting	O
medical	O
conditions	O
that	O
can	O
worsen	O
their	O
atrial	B-Application
fibrillation	I-Application
,	O
such	O
as	O
hyperthyroidism	O
,	O
diabetes	O
,	O
congestive	O
heart	O
failure	O
,	O
high	O
blood	O
pressure	O
,	O
chronic	O
obstructive	O
pulmonary	O
disease	O
,	O
stimulant	O
use	O
(	O
e.g.	O
,	O
methamphetamine	O
dependence	O
)	O
,	O
and	O
excessive	O
alcohol	O
consumption	O
.	O
</s>
<s>
Oral	O
anticoagulation	O
is	O
underused	O
in	O
atrial	B-Application
fibrillation	I-Application
,	O
while	O
aspirin	O
is	O
overused	O
in	O
many	O
who	O
should	O
be	O
treated	O
with	O
a	O
direct	O
oral	O
anticoagulant	O
(	O
DOAC	O
)	O
or	O
warfarin	O
.	O
</s>
<s>
Guidelines	O
from	O
the	O
American	O
College	O
of	O
Chest	O
Physicians	O
,	O
Asia-Pacific	O
Heart	B-Algorithm
Rhythm	I-Algorithm
Society	O
,	O
Canadian	O
Cardiovascular	O
Society	O
,	O
European	O
Society	O
of	O
Cardiology	O
,	O
Japanese	O
Circulation	O
Society	O
,	O
Korean	O
Heart	B-Algorithm
Rhythm	I-Algorithm
Society	O
,	O
and	O
the	O
National	O
Institute	O
for	O
Health	O
and	O
Care	O
Excellence	O
recommend	O
the	O
use	O
of	O
novel	O
oral	O
anticoagulants	O
or	O
warfarin	O
with	O
a	O
CHA2DS2-VASc	O
score	O
of	O
one	O
over	O
aspirin	O
and	O
some	O
directly	O
recommend	O
against	O
aspirin	O
.	O
</s>
<s>
Experts	O
generally	O
advocate	O
for	O
most	O
people	O
with	O
atrial	B-Application
fibrillation	I-Application
with	O
CHA2DS2-VASc	O
scores	O
of	O
one	O
or	O
more	O
receiving	O
anticoagulation	O
though	O
aspirin	O
is	O
sometimes	O
used	O
for	O
people	O
with	O
a	O
score	O
of	O
one	O
(	O
moderate	O
risk	O
for	O
stroke	O
)	O
.	O
</s>
<s>
There	O
is	O
little	O
evidence	O
to	O
support	O
the	O
idea	O
that	O
the	O
use	O
of	O
aspirin	O
significantly	O
reduces	O
the	O
risk	O
of	O
stroke	O
in	O
people	O
with	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
For	O
those	O
with	O
non-valvular	B-Application
atrial	I-Application
fibrillation	I-Application
,	O
DOACs	O
are	O
at	O
least	O
as	O
effective	O
as	O
warfarin	O
for	O
preventing	O
strokes	O
and	O
blood	O
clots	O
embolizing	O
to	O
the	O
systemic	O
circulation	O
(	O
if	O
not	O
more	O
so	O
)	O
and	O
are	O
generally	O
preferred	O
over	O
warfarin	O
.	O
</s>
<s>
Dual	O
antiplatelet	O
therapy	O
with	O
aspirin	O
and	O
clopidogrel	O
is	O
inferior	O
to	O
warfarin	O
for	O
preventing	O
strokes	O
and	O
has	O
comparable	O
bleeding	O
risk	O
in	O
people	O
with	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Warfarin	O
is	O
the	O
recommended	O
anticoagulant	O
choice	O
for	O
persons	O
with	O
valvular	O
atrial	B-Application
fibrillation	I-Application
(	O
atrial	B-Application
fibrillation	I-Application
in	O
the	O
presence	O
of	O
a	O
mechanical	O
heart	O
valve	O
and/or	O
moderate-severe	O
mitral	O
valve	O
stenosis	O
)	O
.	O
</s>
<s>
The	O
exception	O
to	O
this	O
recommendation	O
is	O
in	O
people	O
with	O
valvular	O
atrial	B-Application
fibrillation	I-Application
who	O
are	O
unable	O
to	O
maintain	O
a	O
therapeutic	O
INR	O
on	O
warfarin	O
therapy	O
;	O
in	O
such	O
cases	O
,	O
treatment	O
with	O
a	O
DOAC	O
is	O
then	O
recommended	O
.	O
</s>
<s>
There	O
are	O
two	O
ways	O
to	O
approach	O
atrial	B-Application
fibrillation	I-Application
using	O
medications	O
:	O
rate	O
control	O
and	O
rhythm	O
control	O
.	O
</s>
<s>
Rhythm	O
control	O
tries	O
to	O
restore	O
a	O
normal	O
heart	B-Algorithm
rhythm	I-Algorithm
in	O
a	O
process	O
called	O
cardioversion	O
and	O
maintains	O
the	O
normal	O
rhythm	O
with	O
medications	O
.	O
</s>
<s>
Cardioversion	O
is	O
the	O
attempt	O
to	O
switch	O
an	O
irregular	B-Application
heartbeat	I-Application
to	O
a	O
normal	O
heartbeat	O
using	O
electrical	B-Application
or	O
chemical	O
means	O
.	O
</s>
<s>
Electrical	B-Application
cardioversion	O
involves	O
the	O
restoration	O
of	O
normal	O
heart	B-Algorithm
rhythm	I-Algorithm
through	O
the	O
application	O
of	O
a	O
DC	O
electrical	B-Application
shock	O
.	O
</s>
<s>
Chemical	O
cardioversion	O
is	O
performed	O
with	O
medications	O
,	O
such	O
as	O
amiodarone	O
,	O
dronedarone	O
,	O
procainamide	O
(	O
especially	O
in	O
pre-excited	O
atrial	B-Application
fibrillation	I-Application
)	O
,	O
dofetilide	O
,	O
ibutilide	O
,	O
propafenone	O
,	O
or	O
flecainide	O
.	O
</s>
<s>
Catheter	O
ablation	B-Algorithm
(	O
CA	O
)	O
is	O
a	O
procedure	O
performed	O
by	O
an	O
electrophysiologist	B-Algorithm
,	O
a	O
cardiologist	O
who	O
specializes	O
in	O
heart	B-Algorithm
rhythm	I-Algorithm
problems	O
,	O
to	O
restore	O
the	O
heart	O
's	O
normal	O
rhythm	O
by	O
destroying	O
,	O
or	O
electrically	O
isolating	O
,	O
specific	O
parts	O
of	O
the	O
atria	O
.	O
</s>
<s>
A	O
group	O
of	O
cardiologists	O
led	O
by	O
Dr	O
Haïssaguerre	O
from	O
Bordeaux	O
University	O
Hospital	O
noted	O
in	O
1998	O
that	O
the	O
pulmonary	O
veins	O
are	O
an	O
important	O
source	O
of	O
ectopic	O
beats	O
,	O
initiating	O
frequent	O
paroxysms	O
of	O
atrial	B-Application
fibrillation	I-Application
,	O
with	O
these	O
foci	O
responding	O
to	O
treatment	O
with	O
radio-frequency	O
ablation	B-Algorithm
.	O
</s>
<s>
Most	O
commonly	O
,	O
CA	O
electrically	O
isolates	O
the	O
left	O
atrium	O
from	O
the	O
pulmonary	O
veins	O
,	O
where	O
most	O
of	O
the	O
abnormal	O
electrical	B-Application
activity	O
promoting	O
atrial	B-Application
fibrillation	I-Application
originates	O
.	O
</s>
<s>
CA	O
is	O
a	O
form	O
of	O
rhythm	O
control	O
that	O
restores	O
normal	O
sinus	O
rhythm	O
and	O
reduces	O
AF-associated	O
symptoms	O
more	O
reliably	O
than	O
antiarrhythmic	B-Algorithm
medications	I-Algorithm
.	O
</s>
<s>
Electrophysiologists	B-Application
generally	O
use	O
two	O
forms	O
of	O
catheter	O
ablation	B-Algorithm
—	O
radiofrequency	O
ablation	B-Algorithm
,	O
or	O
cryoablation	O
.	O
</s>
<s>
In	O
young	O
people	O
with	O
little-to-no	O
structural	O
heart	O
disease	O
where	O
rhythm	O
control	O
is	O
desired	O
and	O
cannot	O
be	O
maintained	O
by	O
medication	O
or	O
cardioversion	O
,	O
radiofrequency	O
catheter	O
ablation	B-Algorithm
or	O
cryoablation	O
may	O
be	O
attempted	O
and	O
may	O
be	O
preferred	O
over	O
several	O
years	O
of	O
medical	O
therapy	O
.	O
</s>
<s>
Although	O
radiofrequency	O
ablation	B-Algorithm
has	O
become	O
an	O
accepted	O
intervention	O
in	O
selected	O
younger	O
people	O
and	O
may	O
be	O
more	O
effective	O
than	O
medication	O
at	O
improving	O
symptoms	O
and	O
quality	O
of	O
life	O
,	O
there	O
is	O
no	O
evidence	O
that	O
ablation	B-Algorithm
reduces	O
all-cause	O
mortality	O
,	O
stroke	O
,	O
or	O
heart	O
failure	O
.	O
</s>
<s>
An	O
alternative	O
to	O
catheter	O
ablation	B-Algorithm
is	O
surgical	O
ablation	B-Algorithm
.	O
</s>
<s>
The	O
Maze	O
procedure	O
,	O
first	O
performed	O
in	O
1987	O
,	O
is	O
an	O
effective	O
invasive	O
surgical	O
treatment	O
that	O
is	O
designed	O
to	O
create	O
electrical	B-Application
blocks	O
or	O
barriers	O
in	O
the	O
atria	O
of	O
the	O
heart	O
.	O
</s>
<s>
The	O
idea	O
is	O
to	O
force	O
abnormal	O
electrical	B-Application
signals	O
to	O
move	O
along	O
one	O
,	O
uniform	O
path	O
to	O
the	O
lower	O
chambers	O
of	O
the	O
heart	O
(	O
ventricles	O
)	O
,	O
thus	O
restoring	O
the	O
normal	O
heart	B-Algorithm
rhythm	I-Algorithm
.	O
</s>
<s>
Concomitant	O
AF	O
surgery	O
is	O
more	O
likely	O
to	O
lead	O
to	O
the	O
person	O
being	O
free	O
from	O
atrial	B-Application
fibrillation	I-Application
and	O
off	O
medications	O
long-term	O
after	O
surgery	O
and	O
Cox-Maze	O
IV	O
procedure	O
is	O
the	O
gold	O
standard	O
treatment	O
.	O
</s>
<s>
Postoperative	O
pericardial	O
effusion	O
is	O
also	O
suspected	O
to	O
be	O
the	O
cause	O
of	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
After	O
catheter	O
ablation	B-Algorithm
,	O
people	O
are	O
moved	O
to	O
a	O
cardiac	O
recovery	O
unit	O
,	O
intensive	O
care	O
unit	O
,	O
or	O
cardiovascular	O
intensive	O
care	O
unit	O
where	O
they	O
are	O
not	O
allowed	O
to	O
move	O
for	O
46	O
hours	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
increases	O
the	O
risk	O
of	O
heart	O
failure	O
by	O
11	O
per	O
1000	O
,	O
kidney	O
problems	O
by	O
6	O
per	O
1000	O
,	O
death	O
by	O
4	O
per	O
1000	O
,	O
stroke	O
by	O
3	O
per	O
1000	O
,	O
and	O
coronary	O
heart	O
disease	O
by	O
1	O
per	O
1000	O
.	O
</s>
<s>
Evidence	O
increasingly	O
suggests	O
that	O
atrial	B-Application
fibrillation	I-Application
is	O
independently	O
associated	O
with	O
a	O
higher	O
risk	O
of	O
developing	O
dementia	O
.	O
</s>
<s>
Both	O
the	O
CHADS2	O
and	O
the	O
CHA2DS2-VASc	O
score	O
predict	O
future	O
stroke	O
risk	O
in	O
people	O
with	O
A-fib	B-Application
with	O
CHA2DS2-VASc	O
score	O
being	O
more	O
accurate	O
.	O
</s>
<s>
In	O
atrial	B-Application
fibrillation	I-Application
,	O
the	O
lack	O
of	O
an	O
organized	O
atrial	O
contraction	O
can	O
result	O
in	O
some	O
stagnant	O
blood	O
in	O
the	O
left	O
atrium	O
(	O
LA	O
)	O
or	O
left	O
atrial	O
appendage	O
(	O
LAA	O
)	O
.	O
</s>
<s>
More	O
than	O
90%	O
of	O
cases	O
of	O
thrombi	O
associated	O
with	O
non-valvular	B-Application
atrial	I-Application
fibrillation	I-Application
evolve	O
in	O
the	O
left	O
atrial	O
appendage	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
has	O
been	O
independently	O
associated	O
with	O
a	O
higher	O
risk	O
of	O
developing	O
cognitive	O
impairment	O
,	O
vascular	O
dementia	O
,	O
and	O
Alzheimer	O
disease	O
and	O
with	O
elevated	O
levels	O
of	O
neurofilament	O
light	O
chain	O
in	O
blood	O
,	O
a	O
biomarker	O
indicating	O
neuroaxonal	O
injury	O
.	O
</s>
<s>
Tentative	O
evidence	O
suggests	O
that	O
effective	O
anticoagulation	O
with	O
direct	O
oral	O
anticoagulants	O
or	O
warfarin	O
may	O
be	O
somewhat	O
protective	O
against	O
AF-associated	O
dementia	O
and	O
evidence	O
of	O
silent	O
ischemic	O
strokes	O
on	O
MRI	B-Algorithm
but	O
this	O
remains	O
an	O
active	O
area	O
of	O
investigation	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
is	O
the	O
most	O
common	O
arrhythmia	B-Application
and	O
affects	O
more	O
than	O
33	O
million	O
people	O
worldwide	O
.	O
</s>
<s>
It	O
also	O
accounts	O
for	O
one-third	O
of	O
hospital	O
admissions	O
for	O
cardiac	B-Algorithm
rhythm	I-Algorithm
disturbances	O
,	O
and	O
the	O
rate	O
of	O
admissions	O
for	O
AF	O
has	O
risen	O
in	O
recent	O
years	O
.	O
</s>
<s>
After	O
a	O
transient	O
ischemic	O
attack	O
or	O
stroke	O
,	O
about	O
11%	O
are	O
found	O
to	O
have	O
a	O
new	O
diagnosis	O
of	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
As	O
of	O
2001	O
,	O
it	O
was	O
anticipated	O
that	O
in	O
developed	O
countries	O
,	O
the	O
number	O
of	O
people	O
with	O
atrial	B-Application
fibrillation	I-Application
was	O
likely	O
to	O
increase	O
during	O
the	O
following	O
50years	O
,	O
due	O
to	O
the	O
growing	O
proportion	O
of	O
elderly	O
people	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
is	O
more	O
common	O
in	O
men	O
than	O
in	O
women	O
when	O
reviewed	O
in	O
European	O
and	O
North	O
American	O
populations	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
is	O
an	O
uncommon	O
condition	O
in	O
children	O
but	O
sometimes	O
occurs	O
in	O
association	O
with	O
certain	O
inherited	O
and	O
acquired	O
conditions	O
.	O
</s>
<s>
Congenital	O
heart	O
disease	O
and	O
rheumatic	O
fever	O
are	O
the	O
most	O
common	O
causes	O
of	O
atrial	B-Application
fibrillation	I-Application
in	O
children	O
.	O
</s>
<s>
Other	O
inherited	O
heart	O
conditions	O
associated	O
with	O
the	O
development	O
of	O
atrial	B-Application
fibrillation	I-Application
in	O
children	O
include	O
Brugada	O
syndrome	O
,	O
short	O
QT	O
syndrome	O
,	O
Wolff	O
Parkinson	O
White	O
syndrome	O
,	O
and	O
other	O
forms	O
of	O
supraventricular	B-Algorithm
tachycardia	I-Algorithm
(	O
e.g.	O
,	O
AV	B-Algorithm
nodal	I-Algorithm
reentrant	I-Algorithm
tachycardia	I-Algorithm
)	O
.	O
</s>
<s>
Because	O
the	O
diagnosis	O
of	O
atrial	B-Application
fibrillation	I-Application
requires	O
measurement	O
of	O
the	O
electrical	B-Application
activity	O
of	O
the	O
heart	O
,	O
atrial	B-Application
fibrillation	I-Application
was	O
not	O
truly	O
described	O
until	O
1874	O
,	O
when	O
Edmé	O
Félix	O
Alfred	O
Vulpian	O
observed	O
the	O
irregular	O
atrial	O
electrical	B-Application
behavior	O
that	O
he	O
termed	O
"	O
fremissement	O
fibrillaire	O
"	O
in	O
dog	O
hearts	O
.	O
</s>
<s>
The	O
irregular	O
pulse	O
associated	O
with	O
AF	O
was	O
first	O
recorded	O
in	O
1876	O
by	O
Carl	O
Wilhelm	O
Hermann	O
Nothnagel	O
and	O
termed	O
"	O
delirium	O
cordis	O
"	O
,	O
stating	O
that	O
"[I]n	O
this	O
form	O
of	O
arrhythmia	B-Application
the	O
heartbeats	O
follow	O
each	O
other	O
in	O
complete	O
irregularity	O
.	O
</s>
<s>
Willem	O
Einthoven	O
published	O
the	O
first	O
ECG	B-Application
showing	O
AF	O
in	O
1906	O
.	O
</s>
<s>
The	O
connection	O
between	O
the	O
anatomic	O
and	O
electrical	B-Application
manifestations	O
of	O
AF	O
and	O
the	O
irregular	O
pulse	O
of	O
delirium	O
cordis	O
was	O
made	O
in	O
1909	O
by	O
Carl	O
Julius	O
Rothberger	O
,	O
Heinrich	O
Winterberg	O
,	O
and	O
Sir	O
Thomas	O
Lewis	O
.	O
</s>
<s>
Atrial	B-Application
fibrillation	I-Application
occurs	O
in	O
other	O
animals	O
,	O
including	O
cats	O
,	O
dogs	O
,	O
and	O
horses	O
.	O
</s>
<s>
Cats	O
rarely	O
develop	O
atrial	B-Application
fibrillation	I-Application
but	O
appear	O
to	O
have	O
a	O
higher	O
risk	O
of	O
thromboembolic	O
complications	O
than	O
dogs	O
.	O
</s>
<s>
Cats	O
and	O
dogs	O
with	O
atrial	B-Application
fibrillation	I-Application
often	O
have	O
underlying	O
structural	O
heart	O
disease	O
that	O
predisposes	O
them	O
to	O
the	O
condition	O
.	O
</s>
<s>
The	O
medications	O
used	O
in	O
animals	O
for	O
atrial	B-Application
fibrillation	I-Application
are	O
largely	O
similar	O
to	O
those	O
used	O
in	O
humans	O
.	O
</s>
<s>
Electrical	B-Application
cardioversion	O
is	O
occasionally	O
performed	O
in	O
these	O
animals	O
,	O
but	O
the	O
need	O
for	O
general	O
anesthesia	O
limits	O
its	O
use	O
.	O
</s>
<s>
Standardbred	O
horses	O
appear	O
to	O
be	O
genetically	O
susceptible	O
to	O
developing	O
atrial	B-Application
fibrillation	I-Application
.	O
</s>
<s>
Horses	O
that	O
develop	O
atrial	B-Application
fibrillation	I-Application
often	O
have	O
minimal	O
or	O
no	O
underlying	O
heart	O
disease	O
,	O
and	O
the	O
presence	O
of	O
atrial	B-Application
fibrillation	I-Application
in	O
horses	O
can	O
adversely	O
affect	O
physical	O
performance	O
.	O
</s>
