Download Atrial Fibrillation

Atrial Fibrillation
Overview and Management
What is it?






Most commonly seen narrow complex arrythmia.
Most common irregularly irregular rhythm
Affects more than 10% of age >80.
Men > Women
Multiple impulses from different areas move toward
the AV node.
Produce an irregular ventricular response

Rate depends on # of impulses conducted.
Why is it important?

Can cause significant symptoms usually
secondary to RVR



Range from severe (pulm edema, palpitations,
angina, syncope) to none at all
Prolonged tachycardia may lead to
cardiomyopathy
May lead to clot formation and eventually a
embolic stroke.

Irregular contractions lead to stasis
Classification


Paroxysmal – end <7 days
Persistent – last > 7 days




May terminate on its own or by cardioversion
Permanent - > 1 year and cardioversion has not been
attempted or failed
Lone AF – any of the above without structural heart
disease
Only applies to AF unrelated to a reversible cause
Causes/Associations








Cardiac Surgery
Pericarditis
MI
Hyperthyroidism
PE
Pulmonary disease
Stress, Fever, Excessive EtOH intake, Dehydr.
Treat associated cause and the abnormal rhythm
Diagnosis

History and PE – onset, pattern, frequency,
symptoms, precipitating factors, other
diseases


Symptoms related to severity of underlying heart
disease
EKG – no p waves, irregularly irregular
rhythm, tachycardia
What do we do about it?
Four Issues
1.
2.
3.
4.
Rhythm control
Rate control
Choosing between the two
Prevention of emboli
۞ Choice depends on the type, patient
preference
AAFP/ACP Recommendations on 1st
diagnosed episode of AF





Rate control with chronic anticoagulation is
for the majority
Beta blockers and calcium channel blockers
for rate control
Anticoagulation – warfarin
For rhythm control – both DC and
pharmacologic cardioversion appropriate
After cardioversion – typically no
antiarrythmics
Rhythm Control






Synchronized DC cardioversion and pharmacologic
cardioversion
> 48 hours, or <48 hrs with mitral stenosis or hx of
emboli – you must anticoagulate
3-4 weeks of INR at 2-3
Unless – TEE has excluded thrombi
If unstable –DC cardioversion
If stable and correction of underlying problem does
not help – either choice
Compare Shock vs. Drugs

DC cardioversion – 75-93% successful


Depends on atrial size and duration of AF
Drugs – 30-60% successful


<7 days – dofetilide, flecainide, ibutilide,
propafenone
>7 days – dofetilide
Maintenance of NSR
Only 20-30 percent of patients stay in sinus for >1 year.
Consider Antiarrythmics




Don’t in patients with AF less than 1 year, no atrial
enlargement, reversible cause
Consider it in patients with high risk of recurrence
Risks generally outweigh benefits.
Amiodirone – good, but high toxicity profile, used in
patients with bad heart disease (significant systolic
dysfunction, hypertension with LVH)

Toxicity – pulmonary, photosensitivity, thyroid dysfxn, corneal
deposits, ECG changes, Liver dysfxn
Rate Control

RVR causes



Symptoms and Hemodynamic Instability
Tachycardia mediated cardiomyopathy
Rate control



Achieved by slowing AV conduction (beta
blockers, calcium channel blockers, dig, amio)
Digoxin only in hypotension and Heart Failure
Amiodirone – rarely but effective
AFFIRM trial

Heart Rate Targets – rest and exercise



Resting <80/min
24 hr avg of <100/min and no rate >110 percent
of predicted max for age
<110 beats/min in six minute walk
Essential component is absence of activities
during normal activities or exercise.
Rate vs. Rhythm control
AFFIRM and RACE trials: Two conclusions
1.
Embolic events are equal and occur with low INR
levels or after warfarin stopped
2.
Trend toward a lower incidence of the primary end
point (mortality and event free survival) in rate
control. There was no difference in the quality of
life or functional status.
۞ Rate control is therefore preferred in all except:


Persistent symptoms, Inability to attain rate control,
patient preference
Also consider cardioversion for young healthy
patients and first episodes with low risk of
recurrence. Antiarrythmics usually not used
following cardioversion.
Anticoagulation during reversion to
NSR

AF >48 hrs or unknown




Anticoagulate for >3 weeks, INR 2-3
Or, TEE to eval for clots in LA Appendage – if no
clots – convert.
After, anticoagulate for 4 weeks with warfarin
– “stunned atrium”
Consider chronic anticoagulation for those
with high risk for reversion.
Why chronic anticoagulation once
cardioverted and NSR?


Pt’s at high risk for recurrence –
asymptomatic periods of short AF – produce
thrombi – then embolize (90% of recurrent
episodes not noticed)
Some Pt’s with AF that is not associated with
reversible cause are at high risk for emboli
anyway (aortic plaque, LV systolic dysfxn)
Anticoagulation in Chronic AF







Stroke associated with AF is 3-5%/year without
anticoagulation
Many factors determine ASA vs. warfarin
Estimated risk of stroke is determined with a CHADS2 score
and therapy determined with this scale of 1-6. (CHF, HTN,
Age, DM, Secondary prevention)
0 get ASA because of 0.5%/year w/o coumadin
1-2 intermediate risk
> or = 3 warfarin
P.S. – ASA usually added to warfarin
New Onset Atrial Fibrillation

ER reversion - <48 hrs, uncomplicated, low risk –
convert them and get them out.


1.
2.
3.
4.
Safe and cost effective
Hospitalization Admission Indications
Rule out MI – ST elevation/depression
Treating associated medical problem
Elderly patients
Underlying heart disease with hemodynamic effects
from AF or could be at risk for complication from
therapy
New Onset Contd.

Search for cause – fixing the cause may cause
reversion by itself.


If fixing a cause start heparin as an inpatient and bridge
to coumadin for 3-4 weeks in anticpation of
cardioversion if pt. doesn’t spontaneously convert
Indications for immediate cardioversion
1.
2.
3.
Active ischemia
Hypotension
Severe HF
New Onset contd.

Start rate control – mild to moderate symptoms




Beta blockers, Calcium channel blockers ( verapamil and
diltiazem), and digoxin
Digoxin good for 2nd line or in HF
Can use both BB and Calcium Ch. Blocker together.
Elective Cardioversion


Immediate – if less than 48 hrs and no cardiac
abnormalities
Delayed – anticoagulate first 4 weeks.

Duration >48 hrs, assoc. mitral valve disease or
Cardiomyopathy/HF, prior stroke/TIA