Atrial Fibrillation Atrial Fibrillation Assessment and Management in the ED Joseph R. Cline MD FACEP...
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Atrial Fibrillation 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
Atrial Fibrillation Atrial Fibrillation Assessment and Management in the ED Joseph R. Cline MD FACEP Associate Professor (CHS) Section of Emergency Medicine
Atrial Fibrillation 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
Slide 2
Atrial Fibrillation Objectives 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
Slide 3
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; 285:2370. Atrial Fibrillation -- Prevalence --
Slide 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 < 55 yrs < 0.1% > 55 yrs = 5% >
80 yrs > 9% Life-time risk = 25% for age > 40 yrs (M or F)
Accounts for 15% of all strokes AF increases risk of stroke 5
X
Slide 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
Slide 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; 36;1223) 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
Slide 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
Slide 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 > 4 cm reduced
left ventricular fractional shortening Triggering event majority
related to atrial premature beat minority related to atrial flutter
or atrial tachycardia
Slide 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
Slide 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
Slide 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 S 1 is
diagnostic of atrial fibrillation
Slide 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
Slide 13
Atrial Fibrillation -- ECG -- Aeschmann beats aberrently
conducted beats following a shorter R-R interval than the previous
R-R interval
Atrial Fibrillation -- Lab -- Standard electrolytes assess for
hypokalemia TSH and free T 4 For all cases of new onset Atrial
fibrillation Patients with low TSH and normal free T 4 have
subclinical hyperthyroidism INR Most patients with AF will need
anticoagulation Patients currently anticoagulated need confirmation
of theraputic level
Slide 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
Slide 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
Slide 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 2004;44:
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 388 stable AF encounters (10.5%) Mean age =
61 +/- 13 yrs 332 successful (86%) 56 unsuccessful (14%) 91%
discharged 55% discharged 9% admitted 45% admitted
Slide 19
Atrial Fibrillation -- Management and Disposition -- Urgent or
Emergent cardioversion in the ED What are the indications? What are
the contraindications?
Slide 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 >
48hrs or uncertain duration Associated mitral valve disease,
cardiomyopathy or CHF (known EF < 50%) Prior history of
thromboembolic event
Slide 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 1:1 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
Slide 22
Atrial Fibrillation -- Antiarrhythmic agents --
Slide 23
Fast Channel (Na + ) Action Potential Purkinje fibers Slow
Channel (Ca ++ ) Action Potential Sinus / A-V Nodes 0 1 23 4 2 0
Myocardial Cellular Electrophysiology 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
Slide 24
-- Antiarrythmic Agent Classification Vaughn-Williams
Classification (Journal of Clinical Pharmacology, 1984) Class 1-
depression of Na + conductance 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- -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
Slide 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.
Slide 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
> 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 Rate control as needed ECV if no
thrombi seen
Slide 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
Slide 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, > 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 < 65 yrs
Slide 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
2002;347:1834-40 522 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 Primary endpoint: Rhythm control =
23% Rate control = 17% Follow up period of at least 2 yrs Rhythm
controlRate control Entry: ECV + Sotolol 1 st recurrence: ECV +
Flecanide or Propafenone 2 nd recurrence: Amiodarone load + ECV +
Amiodarone main. Target HR < 100 Digoxin, Diltiazem, blocker
alone or In combination All patients anticoagulated: could be
discontinued if In NSR 4 weeks after ECV
Slide 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
2002;347:1834-40 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
Slide 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, 2000;342:913-920 403
patients; 19 centers 201 Amiodarone202 Propafenone ; Sotolol 101
Propafenone101 Sotolol Mean 16 month follow-up 35% recurrence for
Amiodarone 63% recurrence for Propafenone or Sotolol
Slide 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 blockade or Ca ++ channel blocker to prevent 1:1 AV
conduction if Atrial flutter occurs Class 1c Extended dosing
Amiodarone particularly with patients with pre-existing heart
disease
Slide 33
Atrial Fibrillation -General Management Principles- --
Maintenance of Sinus Rhythm after Chemical or Electrical
Cardioversion ACC / AHA / ESC anticoagulation recommendations
Slide 34
Atrial Fibrillation -General Management Principles- Assessment
of Thromboembolic Risk
Slide 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 > 75 (1)
Diabetes mellitus (1) Stroke, TIA or systemic embolic event
(2)
Atrial Fibrillation -- Prevention of Thromboembolism -- ACC /
AHA / ESC anticoagulation recommendations Age < 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 > 75:Warfarin
Men > 75: Warfarin or Aspirin Age > 65 with CHF:Warfarin EF
< 35% + HypertensionWarfarin
Slide 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 T 4 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