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 - PowerPoint PPT Presentation

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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

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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


1
Atrial FibrillationAssessment and Management in
the EDJoseph R. Cline MD FACEPAssociate
Professor (CHS)Section of Emergency
MedicineUniversity of Wisconsin School of
Medicine and Public Health
2
Atrial 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

3
Atrial 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.
4
Atrial 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

5
Atrial 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

6
Atrial 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

7
Atrial 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

8
Atrial 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

9
Atrial 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

10
Atrial 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

11
Atrial 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

12
Atrial Fibrillation-- ECG --
  • Verification of diagnosis
  • irregularly irregular
  • No discernable P waves
  • Identify associated findings or complications
  • MI
  • LVH
  • Bundle branch block
  • Pre-excitation

13
Atrial Fibrillation-- ECG --
  • Aeschmann beats aberrently conducted beats
    following a shorter R-R interval than the
    previous R-R interval

14
Atrial Fibrillation-- Chest X-ray --
  • Identify heart size, vasculature
  • Assess for additional complicating diseases
  • COPD
  • Pneumonia

15
Atrial 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

16
Atrial 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

17
Atrial 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

18
Atrial 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
19
Atrial Fibrillation-- Management and Disposition
--
  • Urgent or Emergent cardioversion in the ED
  • What are the indications?
  • What are the contraindications?

20
Atrial 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

21
Atrial 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

22
Atrial Fibrillation-- Antiarrhythmic agents --
23
Myocardial 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

25
Atrial 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.

26
Atrial 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

27
Atrial 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

28
Atrial 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

29
Atrial 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
30
Atrial 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

31
Atrial 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
32
Atrial 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

33
Atrial Fibrillation-General Management
Principles--- Maintenance of Sinus Rhythm after
Chemical or Electrical Cardioversion ACC / AHA
/ ESC anticoagulation recommendations
34
Atrial Fibrillation-General Management
Principles-
  • Assessment of Thromboembolic Risk

35
Atrial 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)

36
Atrial 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

37
Atrial 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

38
Atrial 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
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