Download Clinical Slide Set. Atrial Fibrillation

In the Clinic
Atrial Fibrillation
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Who is at risk for atrial fibrillation?
 <1% of individuals aged 60 to 65 years
 8% to 10% of individuals aged >80 years
 Men more than women
 White persons more than black persons
 Presence and severity of underlying heart disease
increases risk
 Sleep-disordered breathing
 Hypertension
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What symptoms and signs should cause
clinicians to suspect atrial fibrillation?
 Palpitations and chest pains (younger patients)
 Fatigue and shortness of breath (elderly)
 Faster-than-expected heart rate
 “Irregularly irregular” time between heart sounds
 Peripheral pulses that vary irregularly in rate, amplitude
 Atrial fibrillation may be asymptomatic
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Is a single electrocardiogram sufficient to
diagnose or exclude atrial fibrillation?
 Yes, a diagnosis is possible if the ECG is recorded
during the arrhythmia, but no, a normal rhythm doesn’t
exclude AF
 If AF suspected, monitor longer with
 Holter monitor
 Patch monitor
 Electrocardiographic loop recorder
 Other ways to identify atrial fibrillation
 Implanted pacemakers
 Implantable defibrillator-cardioverters with atrial leads
 Subcutaneous implanted monitors
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Atrial fibrillation with rapid ventricular rate
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What is the role of history and physical
examination?
 To identify symptom frequency, severity, and duration
 To identify underlying causes
 Structural heart disease
 Other causes and risk factors
 Pulmonary disease, hyperthyroidism
 Use of adrenergic drugs, other stimulants, alcohol
 Diabetes, obesity, sleep-disordered breathing
 Family history of first-degree relatives with atrial
fibrillation
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What other electrocardiographic arrhythmias
can be confused with atrial fibrillation?
 Sinus rhythm with frequent premature atrial contractions
 Atrial flutter
 Atrial tachycardia
 The following electrocardiographic findings identify
atrial fibrillation and help distinguish it from other
arrhythmias
 Irregular ventricular rhythm without recurring pattern
 Absence of P waves
 If the diagnosis is uncertain, examine long recordings from
multiple leads
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Sinus rhythm with frequent premature
atrial contractions
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Atrial flutter
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
How should clinicians classify atrial
fibrillation?
 Paroxysmal: Episodes spontaneously terminate within 7
days (often within 24 hours)
 Persistent: Episodes last >7 days and require an
intervention to restore sinus rhythm
 Long-standing persistent: Continuous atrial fibrillation
for >12 months
 Permanent: Interventions to restore sinus rhythm have
either failed or have not been attempted
 Same patient may be classified into different categories
at different times
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What laboratory studies should clinicians
obtain in patients newly diagnosed with
atrial fibrillation?
 Serum electrolytes and TSH
 Blood tests for renal and hepatic function
 Fecal occult stool test (before starting anticoagulation)
 Transthoracic echocardiography
 Identify structural heart disease
 Identify cardiomyopathy
 Transesophageal echocardiography can rule out atrial
clot when transthoracic images are inadequate and
cardioversion is planned
 Tests may be warranted for PE, acute MI, acute HF
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What underlying conditions should
clinicians look for?
 Structural heart disease
 Atrial fibrosis
 Predisposing conditions
 Acute illness, such as acute MI, PE, thyrotoxicosis
 Use of adrenergic drugs, other stimulants, alcohol
 Recent cardiac or thoracic surgery
 Other types of major surgery, severe illness
 Obesity and sleep apnea
 Family history of first-degree relatives with atrial fibrillation
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
CLINICAL BOTTOM LINE: Diagnosis...
 Typical symptoms
 Palpitations, shortness of breath, exercise intolerance
 Some patients are asymptomatic
 ECG during episode: only way to confirm diagnosis
 Longer monitoring may be helpful (loop recorder)
 Labs: to r/o underlying disorders or contraindications to
therapies
 Echocardiogram: to look for structural heart disease
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Why should atrial fibrillation be treated?
 To reduce symptoms
 Although some patients are asymptomatic
 Other patients have disabling symptoms
 To prevent thromboembolism
 Stroke is the most important event
 Especially in older patients with nonvalvular atrial fibrillation
 To prevent cardiomyopathy
 Persistent tachycardia can lead to cardiomyopathy
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
When should clinicians consider
immediate cardioversion?
 Most patients do not require immediate cardioversion
 Cardioversion can be useful in select circumstances
 Decompensated HF, severe angina, acute infarction,
hypotension, high risk for acute stroke
 Patients with atrial fibrillation and extreme tachycardia, for
example, with Wolff-Parkinson-White syndrome
 Duration <48h in new-onset atrial fibrillation, because clot
is less likely
 Cardioversion can make anticoagulation unnecessary
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Which patients should clinicians consider
hospitalizing?
 Uncertain or unstable underlying arrhythmia
 Acute MI, altered mental status, decompensated HF, or
hypotension
 Intolerable symptoms despite hemodynamic stability
 For elective cardioversion when a monitored, outpatient
setting is not availabl)
 For acute anticoagulation if very-high risk for stroke
 Telemetry monitoring during initiation of certain drugs
 Procedures such as electrophysiological studies, cardiac
catheterization, and catheter or surgical ablation and
placement of pacemakers or implantable defibrillators
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Should clinicians attempt rate control or
rhythm control?
 Rhythm control
 Clinicians traditionally have preferred
 Does not improve mortality, frequency of stroke or
hospitalization, or QOL compared to rate control
 May be useful in patients with severe symptoms and in
younger patients without structural heart disease
 Rate control
 Easier to accomplish
 Prevents exposure to potential adverse effects of
antiarrhythmic agents
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What strategies should clinicians consider
for rate control in patients with rapid atrial
fibrillation?
 Drug therapy: to control ventricular rate in all patients,
even if rhythm control is ultimately the goal
 Traditional target: 60 to 80 beats/min at rest and 90 to 115
beats/min during moderate exercise
 To decrease AV nodal conduction (first-line): β-blockers,
nondihydropyridine calcium-channel antagonists
 To slow conduction through AV node (but not first-line
monotherapy for rate control): digitalis, amiodarone
 To reduce ventricular response if other agents have failed:
amiodarone (difficult to justify due to associated toxicities)
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What strategies should clinicians consider
for rhythm control?
 Electrical cardioversion
 When patient is hemodynamically unstable
 Drug therapy
 Side effects should guide choice of antiarrhythmic drugs
 When atrial fibrillation >48h in duration
 Achieve rate control and adequate anticoagulation first
 Serum potassium should be >4.0, serum magnesium >1.0,
and ionized calcium levels >0.5 mg/dL
(Continued)
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
 Class Ic drugs, such as flecainide and propafenone, are
useful in patients without significant structural heart
disease
 Other class I drugs are used infrequently because of
noncardiac side effects and concern for proarrhythmia
 Class III drugs, such as sotalol and dofetilide, can
prolong the QT interval and cause torsades de pointes
 Amiodarone: permanent liver and lung toxicity is doseand duration-dependent
 Dronedarone: similar in structure to amiodarone but
without iodine and with less antiarrhythmic efficacy
 Contraindicated for decompensated CHF and for
permanent atrial fibrillation
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Drug Therapy for Rate and Rhythm Control
in Atrial Fibrillation
Rate-Controlling Agents
Antiarrhythmic agents Class Ia
Beta-Blockers
oProcainamide
o Metoprolol
oQuinidine gluconate
o Propranolol
oDisopyramide
o Esmolol
Antiarrhythmic agents Class Ic
o Pindolol
oFlecainide
o Atenolol
oPropafenone
o Nadolol
Antiarrhythmic agents Class III
Calcium-channel blockers
oIbutilide
o Verapamil
oAmiodarone
o Diltiazem
oSotalol
Cardiac glycoside
oDofetilide
o Digoxin
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
When should clinicians use antiarrhythmic
drugs to prevent recurrence?
 Only modestly effective in prolonging the time to
recurrence
 One study found amiodarone reduced recurrence more
effectively than sotalol or propafenone
 Therapy considered effective if it
 Reduces the frequency of episodes
 Reduces the frequency of symptoms
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
When is anticoagulation indicated?
 When the risk for thromboembolism exceeds the risk for
serious bleeding from anticoagulation
 When the CHA2DS2-VASc is ≥2
 Guidelines recommend anticoagulation for all patients with
documented atrial fibrillation (symptomatic or
asymptomatic) and ≥2 CHA2DS2-VASc risk factors
 Anticoagulation considered reasonable but not mandatory
when the score is 1
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
CHA2DS2 VASc Score
Characteristic, Points
oCongestive heart failure, 1
oHypertension, 1
oAge ≥ 75 y, 2
oDiabetes mellitus, 1
oStroke/transient ischemic
attack, 2
Guidelines for
Thromboembolic
Prophylaxis
CHA2DS2-VASc Score,
Recommendation
o0, No therapy required
o1, No therapy required but
treatment with aspirin or an
anticoagulant is also
reasonable
o≥ 2, Anticoagulate with
warfarin, dibagatrin,
rivoxaraban, or edoxaban
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What anticoagulation regimens should
clinicians use?
 Warfarin is the traditional choice
 Warfarin reduces strokes better than antiplatelet therapy
and is noninferior to the newer non-vitamin K-dependent
anticoagulants
 When the risk for thromboembolism is lower, start warfarin
without loading dose or concurrent heparin
 When the risk for thromboembolism is higher, hospitalize
and give unfractionated heparin until warfarin target levels
are achieved
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Cardioversion
 Give warfarin for ≥3-4 weeks before to achieve INR 2.03.0 if the duration of atrial fibrillation is undetermined or
≥48h, and continue for ≥4 weeks after cardioversion
 If non-vitamin K-dependent oral anticoagulants are used
instead, give for 3-4 weeks before and continue for ≥4
weeks
 Alternative approach: transesophageal
echocardiography
 If left atrial clot is not present, give 48h unfractionated
heparin or non-vitamin K-dependent oral anticoagulant
before cardioversion, then 4 weeks after cardioversion
 If clot is present, give 4 weeks anticoagulation before
cardioversion and repeat transesophageal echocardiogram
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Aspirin 325 mg/d Can Be an Alternative
 Patient cannot take warfarin or non-vitamin K-dependent
oral anticoagulant
 No previous stroke or transient ischemic attack
 ≤65 years of age
 No hypertension, diabetes, or heart failure
 Aspirin plus clopidogrel prevents more strokes than
aspirin alone, but this combination is not as effective as
warfarin and has an equivalent bleeding risk
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
Non-vitamin K-dependent Anticoagulants
 Noninferior alternatives to warfarin for preventing
thromboembolism
 Don’t require recurrent blood tests to assess INR, minimal
potential for drug-drug interaction, and not influenced by diet
 Act rapidly
 Guidelines for renal dose adjustment
 Lower risk than warfarin for intracranial hemorrhage
 Contraindicated with mechanical heart valves, but can be used
with native valve disease
 Management easier when temporarily discontinued, but
antidotes are more limited than with warfarin
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
When should clinicians consider nondrug
therapies?
 AV nodal ablation therapy
 When pharmacologic rate control cannot be achieved
 Requires pacemaker insertion, can lead to progressive LVD
 Atrial fibrillation ablation therapy
 For highly symptomatic patients with paroxysmal or
persistent atrial fibrillation in whom an attempt at
antiarrhythmic drug therapy has failed
 Not a cure
 Occluding the left atrial appendage is a alternative for
stroke prevention when the risk from anticoagulation is
too high
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
How should clinicians monitor patients?
 Frequency may depend on warfarin monitoring
 Determine whether symptoms are adequately controlled
 Measure resting and exercise heart rates to determine
the adequacy of therapy
 Laboratory tests as needed to assess drug effectiveness
and toxicity
 Switch patients who have not improved on rhythmcontrol drugs to rate-control drugs, or consider
nonpharmacologic therapy
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
CLINICAL BOTTOM LINE: Treatment...
 Goals: reduce symptom frequency and severity, prevent
stroke, prevent tachycardia-related cardiomyopathy
 CHA2DS2-VASC score: to select patients for anticoagulation
 Focus on rate control (target resting rate: 60-110 beats/min)
 Attempt rhythm control if patients do not respond to rate
control or do not tolerate atrial fibrillation
 Atrial fibrillation ablation and AV nodal ablation therapy may
be appropriate when patients remain highly symptomatic
 Closure of the left atrial appendage is an alternative for
thromboembolic protection
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.
What's new in this update?
 Dronedarone is contraindicated for permanent atrial fibrillation
 CHA2DS2-VASC score has become the standard for predicting
thromboembolic risk
 Non-vitamin K-dependent oral anticoagulants are approved as
alternatives to warfarin for thromboembolic prophylaxis
 Reversal agent for dabigatran is now available
 Catheter ablation of parts of the atrium where atrial fibrillation
begins has become a more widely accepted intervention
 Closure of left atrial appendage with atrial occlusion device is
approved for patients at risk of stroke who are unable to take
systemic anticoagulation
© Copyright Annals of Internal Medicine, 2017
Ann Int Med. 166 (3): ITC33–ITC48.