lt1 of individuals aged 60 to 65 years 8 to 10 of individuals aged gt80 years Men more than women White persons more than black persons Presence and severity of underlying heart disease increases risk ID: 774923
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Slide1
Atrial Fibrillation
Slide2Who 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
Slide3What 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
Slide4Is 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
Slide5Atrial fibrillation with rapid ventricular rate
Slide6What 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
Slide7What 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
Slide8Sinus rhythm with frequent premature atrial contractions
Slide9Atrial flutter
Slide10How 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
Slide11What 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
Slide12What 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
Slide13CLINICAL 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
Slide14Why 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
Slide15When 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
Slide16Which 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
Slide17Should 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
Slide18What 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)
Slide19What strategies should clinicians consider for rhythm control?
Electrical cardioversionWhen patient is hemodynamically unstableDrug therapySide effects should guide choice of antiarrhythmic drugsWhen atrial fibrillation >48h in durationAchieve 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)
Slide20Class
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 dose- and 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
Slide21Drug Therapy for Rate and Rhythm Control in Atrial Fibrillation
Rate-Controlling AgentsBeta-BlockersMetoprololPropranololEsmololPindololAtenololNadololCalcium-channel blockersVerapamilDiltiazemCardiac glycosideDigoxin
Antiarrhythmic agents Class Ia
Procainamide
Quinidine gluconate
Disopyramide
Antiarrhythmic agents Class Ic
Flecainide
Propafenone
Antiarrhythmic agents Class III
Ibutilide
Amiodarone
Sotalol
Dofetilide
Slide22When 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
Slide23When is anticoagulation indicated?
When the risk for thromboembolism exceeds the risk for serious bleeding from anticoagulation
When the CHA
2
DS
2
-VASc is
≥2
Guidelines recommend anticoagulation for all patients with documented atrial fibrillation (symptomatic or asymptomatic) and ≥2
CHA
2
DS
2
-VASc risk factors
Anticoagulation considered reasonable but not mandatory when the score is 1
Slide24CHA2DS2 VASc Score
Characteristic, PointsCongestive heart failure, 1Hypertension, 1Age ≥ 75 y, 2Diabetes mellitus, 1Stroke/transient ischemic attack, 2
Guidelines for Thromboembolic Prophylaxis
CHA2DS2-VASc Score, Recommendation0, No therapy required1, No therapy required but treatment with aspirin or an anticoagulant is also reasonable≥ 2, Anticoagulate with warfarin, dibagatrin, rivoxaraban, or edoxaban
Slide25What 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
Slide26Cardioversion
Give warfarin for ≥3-4 weeks before to achieve INR 2.0-3.0 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
Slide27Aspirin 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
Slide28Non-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
Slide29When 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
Slide30How 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 rhythm-control drugs to rate-control drugs, or consider nonpharmacologic therapy
Slide31CLINICAL BOTTOM LINE:
Treatment...
Goals: reduce symptom frequency and severity, prevent stroke, prevent tachycardia-related cardiomyopathy
CHA
2
DS
2
-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
Slide32What's new in this update?
Dronedarone is contraindicated for permanent atrial fibrillation
CHA
2
DS
2
-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