Title: Atrial Fibrillation Assessment and Management in the ED Joseph R. Cline MD FACEP Associate Professor (CHS) Section of Emergency Medicine University of Wisconsin School of Medicine and Public Health
1Atrial FibrillationAssessment and Management in
the EDJoseph R. Cline MD FACEPAssociate
Professor (CHS)Section of Emergency
MedicineUniversity of Wisconsin School of
Medicine and Public Health
2Atrial FibrillationObjectives
- Review prevalence and associated and confounding
conditions - Review clinical assessment and categorization
- Review management strategy
- Discuss classification of antiarrhythmics and the
use in AF - Discuss thromboembolic risk in AF
3Atrial Fibrillation-- Prevalence --
In a cross-sectional study of almost 1.9 million
men and women, the prevalence of atrial
fibrillation increases with age, ranging from
0.1 for those less than 55 years of age to over
9 percent in those 85 years of age. At all
ages, the prevalence is higher in men than women.
Data from Go, AS, Hylek, EM, Phillips, K, et al,
JAMA 2001 2852370.
4Atrial Fibrillation-- Incidence and Prevalence --
- Overall prevalence 0.4 of U.S. population
- From 1996-2001, primary hospital discharge
diagnosis of Atrial fibrillation increased by 34
- Most common arrhythmia in the ED setting 1 3
of ED visits overall - Prevalence age lt 55 yrs lt 0.1
- gt 55 yrs 5
- gt 80 yrs gt 9
- Life-time risk 25 for age gt 40 yrs (M or F)
- Accounts for 15 of all strokes
- AF increases risk of stroke 5 X
5Atrial Fibrillation-- Classification --
- Paroxysmal AF duration less than 7 days and may
be recurrent - Persistent AF fails to self-terminate duration
greater than 7 days can be terminated by
cardioversion - Permanent AF duration more than 1 year
cardioversion either failed or has not been
attempted - Lone AF paroxysmal, persistent, or permanent
AF without structural heart disease
6Atrial Fibrillation -- Prevalence in associated
diseases --
- Hypertension increased relative risk of only
1.42 however prevalence of hypertension accounts
for the high association - CAD AF is transient in 6-10 of MI patients
however it is almost never in isolation to other
ECG findings of ACS (Zimetbaum et al. Incidence
and predictors of myocardial infarction among
patients with atrial fibrillation. J Am Coll
Cardiol 2000 361223) - Incidence in chronic, stable CHD is 0.6
- Valvular heart disease
- High prevalence with Rheumatic heart disease
- MS MR 52
- MS alone 29
- MR alone - 16
- AS alone 1
- Degenerative MR incidence 5 per year
7Atrial Fibrillation-- Prevalence in associated
diseases, cont. --
- Heart Failure 10-30
- Pulmonary embolism 10-14 (rarely the only
sign or symptom) - Hyperthyroidism low TSH in 5.4 clinical
hyperthyroidism present in 1 - COPD
- Post cardiac surgery
- Pericarditis
- Obstructive sleep apnea ( for patients with AF
and OSA, incidence of AF recurrence is 2X for
those not treated with CPAP) - Congenital heart disease
- Peripartum cardiomyopathy
- Holiday Heart
8Atrial Fibrillation-- Pathogenesis --
- Underlying heart disease of any cause that is
complicated by - heart failure
- atrial enlargement
- elevated atrial pressure
- inflammation or infiltration of the atria
- Echocardiographic risk factors
- increased left ventricular wall thickness
- left atrial diameter gt 4 cm
- reduced left ventricular fractional shortening
- Triggering event
- majority related to atrial premature beat
- minority related to atrial flutter or atrial
tachycardia
9Atrial Fibrillation-- History and Physical Exam
--
- Define symptoms
- Define pattern
- Paroxysmal
- Persistent
- Recurrent
- Permanent
- Onset or date of discovery
- Frequency and duration of episodes
- Precipitating causes and modes of termination
10Atrial Fibrillation-- History --
- Symptoms
- Palpitations, weakness, dizziness, reduced
exercise capacity, dyspnea - Angina, CHF symptoms, syncope (hypotension)
relate to underlying heart disease - Up to 90 of episodes are asymptomatic with
approximately 20 of such episodes longer than 48
hrs - 90 of AF patients have recurrent episodes
11Atrial Fibrillation-- Exam --
- ABCs
- Vital signs
- Rate / BP to assess perfusion and guide decision
for urgent / emergent ECV - Assess for signs of CHF
- Heart tones variable intensity of S1 is
diagnostic of atrial fibrillation
12Atrial Fibrillation-- ECG --
- Verification of diagnosis
- irregularly irregular
- No discernable P waves
- Identify associated findings or complications
- MI
- LVH
- Bundle branch block
- Pre-excitation
13Atrial Fibrillation-- ECG --
- Aeschmann beats aberrently conducted beats
following a shorter R-R interval than the
previous R-R interval
14Atrial Fibrillation-- Chest X-ray --
- Identify heart size, vasculature
- Assess for additional complicating diseases
- COPD
- Pneumonia
15Atrial Fibrillation-- Lab --
- Standard electrolytes assess for hypokalemia
- TSH and free T4
- For all cases of new onset Atrial fibrillation
- Patients with low TSH and normal free T4 have
subclinical hyperthyroidism - INR
- Most patients with AF will need anticoagulation
- Patients currently anticoagulated need
confirmation of theraputic level
16Atrial Fibrillation-- Management and Disposition
--
- Which category?
- Recent onset AF
- Recurrent paroxysmal AF
- Recurrent persistent AF
- Permanent (Chronic) AF
- and patient condition, determines
- Which primary option
- Rate control
- Urgent cardioversion
- Delayed cardioversion
- Rhythm control / maintenance if converted
- Systemic embolization prevention
17Atrial Fibrillation-- Management and Disposition
--
- Elective cardioversion in the ED
- duration clearly identified less than 48 hrs
- No reversible cause
- low risk of intra-cardiac thrombus formation
18Atrial Fibrillation-- ED Cardioversion in the
stable patient --
- Burton, John H. et al. Electrical cardioversion
of ED patients with Atrial Fibrillation. Annals
of Emergency Medicine 200444 22-30
Retrospective, consecutive cohort 42 months, Oct
1998 March 2002 4 institutions 3,688 AF
encounters
Excluded Cardioversion for unstable
patients hypotension, dyspnea, ischemic chest
pain, altered consciousness, CHF, acute MI
No standardized protocol at any of the study sites
91 discharged
332 successful (86)
9 admitted
388 stable AF encounters (10.5) Mean age 61
/- 13 yrs
55 discharged
56 unsuccessful (14)
45 admitted
19Atrial Fibrillation-- Management and Disposition
--
- Urgent or Emergent cardioversion in the ED
- What are the indications?
- What are the contraindications?
20Atrial Fibrillation-- Management and Disposition
--
- Urgent cardioversion
- Restoration of sinus rhythm takes precedence
over mitigation of thromboembolic risk - Indicated if any of the following is present
- Active ischemia
- Significant hypotension where LV dysfunction
(systolic or diastolic) or valvular disease is a
factor - Severe CHF
- Pre-excitation syndrome (eg WPW)
- Relative Contraindications to urgent
cardioversion - Duration of episode gt 48hrs or uncertain duration
- Associated mitral valve disease, cardiomyopathy
or CHF (known EF lt 50) - Prior history of thromboembolic event
-
21Atrial Fibrillation-- Management and Disposition
--
- Rate control
- indicated if starting Class 1a or 1c
antiarrhythmic drug due to possible recurrence
with Atrial flutter with 11 conduction - Necessary for prevention of tachycaria-induced
left venticular dysfunction - Agents for rate control
- Beta blockers
- IV therapy Metoprolol, Esmolol
- Oral therapy Atenolol
- Calcium channel blockers
- Diltiazem
- Verapamil
- Digoxin
- Useful only in CHF patients or as second/third
line agent
22Atrial Fibrillation-- Antiarrhythmic agents --
23Myocardial Cellular Electrophysiology
Fast Channel (Na) Action Potential Purkinje
fibers
Slow Channel (Ca) Action Potential Sinus / A-V
Nodes
1
2
0
2
3
0
4
Class 1 antiarrhythmics -Slowing of
conductance -Phase 0 is determined by Na
channel -Slowing of conduction velocity and
decreased excitability
Class 4 antiarrhythmics -Slowing of AV nodal
conductance -Phase 0 is determined by Ca
channel -Slowing of conduction velocity in
sinus and AV nodes
24-- Antiarrythmic Agent ClassificationVaughn-Will
iams Classification (Journal of Clinical
Pharmacology, 1984)
- Class 1- depression of Naconductance during
phase 0 slowed conduction velocity and decreased
excitability - 1a moderate depression of Na conductance in
resting and depolarized tissue depression
of K currents and prolongation of repolarization - Quinidine, Procainamide, Disopyramide
- 1b depression of Na conductance in depolarized
fibers only - Lidocaine, Tocainide, Phenytoin
- 1c marked depression in Na conduction no
effect on repolarization - Encainide, Flecainide, Propafenone
- Class 2- ß-adrenergic receptor blockers
- Atenolol, Metoprolol
- Class 3- prolongation of action potential
duration by varied effects - Bretylium, Sotolol, Amiodarone, Ibutilide,
Dofetilide - Class 4- depression of Ca-dependent slow
channels - Diltiazem, Verapamil
25Atrial Fibrillation-- Management and Disposition
--
- Delayed cardioversion
- AF duration of 48 hours or duration unknown
- Associated mitral valve disease, cardiomyopathy
or CHF - Prior history of thromboembolic event
- Anticoagulate with a goal INR of 2.0 to 3.0 for
at least three weeks before and four weeks after
either electrical or pharmacologic cardioversion.
26Atrial Fibrillation-- Management and Disposition
for Delayed ECV --
- Strategy 1 (Conventional)
- Oral anticoagulation with Warfarin
- Target INR 2.0 3.0
- No antiarrythmics
- Rate control as needed hospitalization usually
necessary if rate control needed - Metoprolol
- Diltiazem
- Digoxin (useful only in presence of CHF)
- Scheduled ECV after minimum of 3 weeks of
anticoagulation - 4 weeks of anticoagulation after ECV
- Strategy 2
- Indication
- recent onset but gt 48 hrs
- useful for hospitalized patients (rate control,
associated complications) and stable patients for
which earlier timing is useful - Patients with increased risk of hemorrhage with
anticoagulation - Screening Transesophageal echocardiography (TEE)
- No anticoagulation
- No antiarrhythmics
27Atrial Fibrillation -- Indications for
hospitalization --
- For the treatment of an associated medical
problem, which is often the reason for the
arrhythmia - For elderly patients who are more safely treated
for AF in hospital - For patients with underlying heart disease who
have hemodynamic consequences from the AF or who
are at risk for a complication resulting from
therapy of the arrhythmia
28Atrial Fibrillation-- Rate control alone vs
rhythm control--
- Rhythm control strategy
- Advantages
- Better exertional capacity
- Improved cardiac function for CHF patients
- Mitigation of other arrhythmic related symptoms
(eg palpitations) - Disadvantages
- frequent recurrences of AF 50 of patient
recurr in 3-6 months - repeated need for electrical cardioversion
- adverse effects of prophylactic antiarrhythmic
drugs including life-threatening events related
to proarrhythmic effects - No clear benefit of either approach for patients
over 65 years of age trend for increased
mortality in rhythm control (AFFIRM trial, NEJM
2002, gt 4,000 patients) - Rate control with anticoagulation is acceptable
in patients 65 yrs or greater - Strategy is weighed for acutely symptomatic
patient with new onset of Atrial fibrillation,
particularly if lt 65 yrs
29Atrial Fibrillation-- Rate control alone vs
rhythm control --
- VanGelder, et al, A Comparison of Rate Control
and Rhythm Control in Patients with Recurrent
Persistent Atrial Fibrillation, NEJM
20023471834-40
Follow up period of at least 2 yrs
522 Patients with persistent AF after previous
electrical cardioversion Mean age
68 /- 8 Mean
duration of AF diagnosis 315 d Mean
duration of presenting episode 32 d No history
of heart disease 21
Primary Endpoints Death CHF TE event
Bleeding Pacer severe drug adverse event
Rhythm control
Rate control
Primary endpoint Rhythm control 23 Rate
control 17
Entry ECV Sotolol
Target HR lt 100 Digoxin, Diltiazem, ß blocker
alone or In combination
1st recurrence ECV Flecanide or Propafenone
2nd recurrence Amiodarone load ECV
Amiodarone main.
All patients anticoagulated could be
discontinued if In NSR 4 weeks after ECV
30Atrial Fibrillation-- Rate control alone vs
rhythm control --
- VanGelder, et al, A Comparison of Rate Control
and Rhythm Control in Patients with Recurrent
Persistent Atrial Fibrillation, NEJM
20023471834-40
- Factors related to lack of risk reduction with
rhythm control strategy - Tachycardia induced cardiomyopathy and heart
failure also are - likely reduced with rate control (incidence of
CHF similar in - the two arms of the study)
- Patients with risk factors for stroke are still
at risk for stroke even - when sinus rhythm is maintained (17 of the
thromboembolic - events occurred after cessation of anticoagulant
therapy and in - 5 of 6 cases the patient was in sinus rhythm at
the time of the event) - Senescent conduction disease is occasionally
unmasked by rhythm - control strategy
31Atrial Fibrillation-- Maintenance of Sinus
Rhythm after Chemical or Electrical Cardioversion
--
- Canadian Trial of Atrial Fibrillation
Investigators - Roy, et al Amiodarone to Prevent Recurrence of
Atrial Fibrillation, NEJM, 2000342913-920
403 patients 19 centers
201 Amiodarone
202 Propafenone Sotolol
101 Propafenone
101 Sotolol
Mean 16 month follow-up
35 recurrence for Amiodarone
63 recurrence for Propafenone or Sotolol
32Atrial Fibrillation-General Management
Principles--- Pharmacologic Cardioversion --
- Semi urgent (hospitalization or Obs Unit)
- Class 1c
- used only if no pre-existant heart disease
- monitoring for rapid conducting At. Flutter
- Flecainide
- Propafenone
- Class 3
- monitoring for QT prolongation Torsade
- Dofetilide
- Ibutilide
- Out-patient / Ambulatory scenario
- Class 1c Pill-in-the-Pocket
- Flecainide
- Propafenone
- Used only when demonstrated effective under as
in-patient - Must have AV nodal blockade with ß blockade or
Ca channel blocker to prevent 11 AV conduction
if Atrial flutter occurs - Class 1c Extended dosing
- Amiodarone particularly with patients with
pre-existing heart disease
33Atrial Fibrillation-General Management
Principles--- Maintenance of Sinus Rhythm after
Chemical or Electrical Cardioversion ACC / AHA
/ ESC anticoagulation recommendations
34Atrial Fibrillation-General Management
Principles-
- Assessment of Thromboembolic Risk
35Atrial Fibrillation-- Risk for Thromboembolism --
- Go, AS, Hylek, EM, Chang, Y, et al, JAMA 2003
- Risk assessment CHADS2
- CHF any history
(1) - Hypertension prior history (1)
- Age gt 75
(1) - Diabetes mellitus
(1) - Stroke, TIA or systemic embolic event (2)
-
36Atrial Fibrillation-- Risk for Thromboembolism --
- Risk assessment CHADS2
- Go, AS, Hylek, EM, Chang, Y, et al, JAMA 2003
- Score (risk) Event rate ( /
yr) - Warfarin Without Warfarin
NNT - 0 (low) 0.25 0.49 417
- 1 (interm) 0.72 1.52 125
- 2 (interm) 1.27 2.50 81
- 3 (high) 2.2 5.27 33
- 4 (high) 2.35 6.02 27
- 5,6 (high) 4.6 6.88
-
37Atrial Fibrillation-- Prevention of
Thromboembolism --
- ACC / AHA / ESC anticoagulation recommendations
- Age lt 60 heart disease but no other risks
Aspirin - Age 60 75 with no risks Aspirin
- Age 65 75 with heart disease or DM
Warfarin - Women gt 75 Warfarin
- Men gt 75 Warfarin or Aspirin
- Age gt 65 with CHF Warfarin
- EF lt 35 Hypertension Warfarin
-
38Atrial Fibrillation-- Summary
- Patients with new onset atrial fibrillation of
less than 48 hrs duration, who have normal
ventricular function, no known mitral valvular
disease and no history of thromboembolic event
can be considered for cardioversion in the ED - Up to 90 of atrial fibrillation episodes are
asymptomatic with approximately 20 of such
episodes longer than 48 hrs (Select your
cardioversion cases carefully!) - If the episode is greater than 48hrs, rate
control, anticoagulate and refer for delayed
cardioversion - TSH and free T4 are essential in the evaluation
of initial onset - AF is transient in 6-10 of MI patients however
it is almost never in isolation to other ECG
findings of ACS - CHAD2 scheme is extremely helpful in assessing
thromboembolic risk and need for anticoagulation - In patients greater than age 65, rhythm control
strategy is very appropriate - AF is transient in 6-10 of MI patients however
it is almost never in isolation to other ECG
findings of ACS