Atrial Fibrillation Guidelines

Updated: Apr 10, 2017
  • Author: Lawrence Rosenthal, MD, PhD, FACC, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Guidelines

Atrial Fibrillation Classification

Guideline contributor: Noel G Boyle, MB, BCh, MD, PhD, Professor of Medicine, UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center.

Atrial fibrillation classification

In 2014, the American Heart Association/American College of Cardiology/Heart Rhythm Society (AHA/ACC/HRS) released updated guidelines for the management of patients with atrial fibrillation (AF). These guidelines supersede the AF guideline published in 2006 and updated in 2011. The guidelines provide the following revised classification schema, based on duration of episodes [1]

  • Paroxysmal AF: Episodes of AF that terminate spontaneously or with intervention within 7 days; may recur with variable frequency
  • Persistent AF: Episodes of continuous AF that last more than 7 days and do not self-terminate
  • Long-standing persistent AF: Episodes of continuous AF that last more than 12 months
  • Permanent AF: Applies when a joint physician/patient decision has been made to accept the presence of AF and stop further attempts to restore and/or maintain sinus rhythm (as this represents clinical acceptance rather than an inherent pathophysiological attribute of AF, it is understood that acceptance of AF may change as symptoms, efficacy of interventions, and patient/physician preferences evolve)
  • Nonvalvular AF: AF in the absence of rheumatic mitral valve disease, a prosthetic heart valve, or mitral valve repair

It is further noted that episodes often increase in frequency and duration over time. In addition, the term “lone AF” to identify AF in typically younger patients without structural heart disease, hypertension, or diabetes mellitus is deemed potentially confusing and should not be used to guide treatment decisions. [1]

The European Society of Cardiology (ESC) utilizes a similar classification schema published in its 2010 guidelines. The ESC included one additional characterization, silent AF (asymptomatic), which can manifest as AF-related complications such as ischemic stroke or tachycardiomyopathy, or is diagnosed incidentally on electrocardiography (ECG). Any form of AF may be silent or asymptomatic. [140]

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Stroke Risk Assessment

Guidelines have been issued by the following organizations for prevention of stroke in atrial fibrillation (AF) patients:

  • 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society (AHA/ACC/HRS)
  • 2012 European Society of Cardiology (ESC)
  • 2014 American Academy of Neurology (AAN)
  • 2012 American College of Chest Physicians (ACCP)

All major guidelines note that one of the major management decisions in AF is determining the risk of stroke and the appropriate anticoagulation regimen for low-, intermediate-, and high-risk patients. For each anticoagulant, the benefit in terms of stroke reduction must be weighed against the risk of serious bleeding, with the risk-benefit ratio generally considered not advantageous in low-risk patients with AF. Thus, the guidelines stress that clinical judgment and patient preferences should play a major role in shared decision making. [1, 89, 141, 142]

The CHADS2 score (Cardiac failure, Hypertension, Age >75 years, Diabetes, prior Stroke or TIA [transient ischemic attack]) is the most widely used algorithm to determine yearly thromboembolic risk. Two points are assigned for a history of stroke or TIA, and 1 point is given for age older than 75 years or a history of hypertension, diabetes, or heart failure. [57]

The ACCP bases its recommendations for antithrombotic therapy in patients with nonvalvular atrial fibrillation (NVAF) on the CHADS2 score, as follows [142] :

  • CHADS 2 score = 0 (low risk): No antithrombotic therapy
  • CHADS 2 score ≥1 (intermediate or high risk): Oral antithrombotic therapy

However, the 2014 AHA/ACC/HRS and 2012 updated ESC guidelines both recommend that the CHADS2 score be replaced with the more comprehensive CHA2DS2-VASc score. [1, 141] In this scoring system, points are assigned as follows [58] :

  • Congestive heart failure (CHF): 1 point
  • Hypertension: 1 point
  • Age ≥75 years: 2 points
  • Diabetes: 1 point
  • Stroke, TIA, or thromboembolism history: 2 points
  • Vascular disease (myocardial infarction [MI], peripheral arterial disease, aortic plaque): 1 point
  • Age 65-74 years: 1 point
  • Sex category (female sex): 1 point

The AHA/ACC/HRS further recommends that antithrombotic therapy should be based on the risk of thromboembolism irrespective of whether the AF pattern is paroxysmal, persistent or permanent. [1]

In 2014, the American Heart Association (AHA) also issued joint guidelines with the American Stroke Association (ASA) for the primary prevention of stroke, which included specific recommendations for stroke prevention in patients with AF. The main advantage of the CHA2DS2-VASc score (range, 0-9) is that it provides significantly improved risk prediction for individuals at low to moderate risk compared with the CHADS2 (scores of 0 or 1), particularly for elderly women. [143]

The AHA/ACC/HRS recommendations for antithrombotic therapy in patients with AF, based on CHA2DS2-VASc scores, are as follows [1] :

  • NVAF and CHA 2DS 2-VASc score = 0: No antithrombotic therapy
  • NVAF and CHA 2DS 2-VASc score = 1: No antithrombotic therapy or oral antithrombotic therapy
  • Prior stroke, TIA or CHA 2DS 2-VASc Score ≥2: Oral antithrombotic therapy

The ESC offers varying recommendations for patients with AF based on CHA2DS2-VASc scores, as follows [141] :

  • CHA 2DS 2-VASc score = 0: No antithrombotic therapy
  • CHA 2DS 2-VASc score = 1: Oral anticoagulants
  • CHA 2DS 2-VASc score ≥2: Oral anticoagulants

The shift from the CHADS2 score to the CHA2DS2-VASc score has not been without controversy. The number of patients eligible for oral anticoagulant therapy in the United States is estimated to increase by nearly 1 million, raising concerns about the associated increase in bleeding complications. An analysis by O’Brien and colleagues concluded that using the 2014 AHA/ACC/HRS recommendations to guide the management of AF would result in 98.5% of patients 65 years of age and older and 97.7% of women with AF receiving a definitive recommendation for oral anticoagulant therapy. [144]

The 2014 AAN revised guidelines for stroke prevention in NVAF recommend use of risk stratification to aid in clinical decision making, but do not recommend the use of any specific tool. Furthermore, the guidelines caution against use of strictly interpreted thresholds as definitive indicators for which patients require anticoagulation therapy. Additional recommendations for patient selection included the following [89] :

  • Anticoagulation therapy should be offered to all patients with NVAF and a history of ischemic attack or stroke
  • Anticoagulation therapy should not be offered to patients with NVAF who lack additional risk factors; these patients may be offered aspirin therapy or no antithrombotic therapy
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Antithrombotic Therapy

The major guidelines vary considerably in their recommendations for antithrombotic therapy. See the table below.

Table. Antithrombotic Therapy Recommendations for Atrial Fibrillation (Open Table in a new window)

Issuing Organization Year Patient Groups Antithrombotic Therapy
American Heart Association/American College of Cardiology/ Heart Rhythm Society (AHA/ACC/HRS) [1] 2014
  • AF with mechanical heart valve
  • With prior stroke, TIA or CHA 2DS 2-VASc score ≥2
  • NVAF and CHA 2DS 2-VASc score ≥2
  • NVAF with CHA 2DS 2-VASc score ≥2 and end-stage CKD or on hemodialysis
  • NVAF with CHA 2DS 2-VASc score ≥2 and moderate to severe CKD
  • All patients
  • Warfarin therapy; target INR, 2.0-3.0 or 2.5-3.5 based on type and location of prosthesis
  • Bridging therapy with unfractionated heparin or LMWH for patients undergoing procedures that require interruption of warfarin. Decisions on bridging therapy should balance the risks of stroke and bleeding.
  • Oral anticoagulants: Warfarin (INR 2.0-3.0), dabigatran, apixaban, or rivaroxaban
  • Warfarin (INR 2.0-3.0); if unable to maintain a therapeutic INR level with warfarin, use of a direct thrombin or factor Xa inhibitor (dabigatran, rivaroxaban, or apixaban)
  • Warfarin (INR 2.0-3.0); direct thrombin or factor Xa inhibitors are not recommended
  • Reduced doses of direct thrombin or factor Xa inhibitors may be considered (eg, dabigatran, rivaroxaban, apixaban), but safety and efficacy have not been established
  • In patients receiving warfarin, the INR should be determined at least weekly during initiation of antithrombotic therapy and at least monthly when anticoagulation (INR in range) is stable
  • Periodic reevaluation of the need and choice of anti-thrombotic therapy to reassess stroke and bleeding risks
American Heart Association/American Stroke Association (AHA/ASA) [143] 2014
  • Valvular AF/ CHA 2DS 2-VASc score ≥2
  • NVAF// CHA 2DS 2-VASc score ≥2 and low risk for hemorrhagic complications
  • NVAF, CHA 2DS 2-VASc score = 1, and low risk for hemorrhagic complications
  • Warfarin therapy; target INR, 2.0-3.0
  • Oral anticoagulant (warfarin, dabigatran, apixaban, or rivaroxaban) individualized based on patient risk factors (particularly risk for intracranial hemorrhage), cost, tolerability, patient preference, potential for drug interactions, and other clinical characteristics.
  • No antithrombotic therapy, anticoagulant therapy, or aspirin therapy may be considered
American Academy of Neurology (AAN) [89] 2014
  • NVAF and history of TIA or stroke; age >75 years, if no history of unprovoked bleeding or intracranial hemorrhage; patients with dementia or occasional falls; however in patients with moderate to severe dementia or frequent falls, risk-benefit ratio is uncertain
  • Patients at moderate stroke risk in developing countries where newer anticoagulants are unavailable
  • Warfarin, target INR 2.0 to 3.0
  • Dabigatran, rivaroxaban, or apixaban (preferred) if at high risk for intracranial bleeding or unable to submit to frequent periodic INR testing
  • Apixaban, if at increased risk for gastrointestinal bleeding
  • Triflusal 600 mg/day plus moderate-intensity anticoagulation (INR 1.25–2.0) with acenocoumarol is likely more effective than acenocoumarol alone at the higher INR (2.0-3.0)
American College of Chest Physicians (ACCP) [142] 2012 NVAF intermediate risk (CHADS2 score = 1) or high risk (CHADS2 score ≥2)
  • Oral anticoagulants: dabigatran 150 mg BID preferred over warfarin (target INR range, 2.0-3.0)
  • Patients who are unsuitable for or choose not to take an oral anticoagulant (for reasons other than concerns about major bleeding): combination therapy with aspirin and clopidogrel
European Society of Cardiology (ESC) [141] 2012
  • CHA 2DS 2-VASc score = 0, and females aged <65 years with CHA 2DS 2-VASc score = 1
  • CHA 2DS 2-VASc score = 1
  • CHA 2DS 2-VASc score ≥2
  • All patients
  • Patients who refuse oral anticoagulants
  • No antithrombotic therapy
  • Oral anticoagulants: Warfarin (INR 2.0-3.0) or dabigatran or rivaroxaban or apixaban based on assessment of risk of bleeding
  • Oral anticoagulants: Dabigatran or rivaroxaban or apixaban preferred over warfarin (INR 2.0-3.0)
  • When dabigatran is considered, 150 mg BID preferred; 110 mg BID is preferred for ages ≥80 years, concomitant use of interacting drugs, high bleeding risk or moderate renal impairment
  • When rivaroxaban is considered, 20 mg OD preferred; 15 mg OD is preferred for those with high bleeding risk or moderate renal impairment
  • Baseline and subsequent annual assessment of renal function (by CrCl) is recommended in patients following initiation of any novel oral anticoagulant (dabigatran, rivaroxaban, and apixaban), and 2-3 times per year in those with moderate renal impairment; novel oral anticoagulants are not recommended in patients with severe renal impairment (CrCl <30 mL/min)
  • Antiplatelet therapy should be considered, using combination therapy with aspirin 75–100 mg plus clopidogrel 75 mg daily (where there is a low risk of bleeding) or—less effectively—aspirin 75–325 mg daily
Note: Edoxaban was approved by the FDA in January 2015 for use as an oral anticoagulant in atrial fibrillation.



 



AF = atrial fibrillation; BID = twice daily; CKD = chronic kidney disease; CrCl = creatinine clearance; INR = international normalized ratio; LMWH = low-molecular-weight heparin; NVAF = nonvalvular atrial fibrillation; OD = before bedtime; TIA = transient ischemic attack.



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Rate Control

The 2014 American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Rhythm Society (HRS) guidelines include the following recommendations for control of ventricular rate in patients with atrial fibrillation (AF) [1] :

  • Beta-blockers or non-dihydropyridine calcium channel blockers are first-line agents for paroxysmal, persistent or permanent AF.
  • Intravenous (IV) beta-blockers or non-dihydropyridine calcium channel blockers may be used to slow ventricular heart rate in an acute setting in patients without preexcitation; in hemodynamically unstable patients, electrical cardioversion is indicated.
  • Consider IV amiodarone for rate control in critically ill patients without preexcitation if the condition limits the use of beta-blockers or calcium channel blockers.
  • In patients with AF symptoms during activity, assess heart rate control during exertion, adjusting drug treatment as needed.
  • Heart rate control (defined as <80 bpm at rest) may be considered for less symptomatic patients with AF; a more lenient rate-control strategy (<110 bpm at rest) is reasonable when patients remain asymptomatic and left ventricular (LV) systolic function is preserved.
  • In patients with inadequate ventricular rate control despite drug therapy, atrioventricular (AV) nodal ablation and pacemaker implantation may be considered.
  • AV nodal ablation should not be performed without prior attempts to achieve rate control with medications.
  • Non-dihydropyridine calcium channel blockers are contraindicated in decompensated heart failure.
  • With preexcitation syndrome and AF, non-dihydropyridine calcium channel blockers, digoxin, and IV amiodarone are contraindicated.
  • Dronedarone should not be used in patients with permanent AF or class III or IV heart failure.
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Cardioversion

The 2014 American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Rhythm Society (HRS) guidelines provide the following recommendations regarding cardioversion of atrial fibrillation (AF) [1] :

  • AF of ≥48 hours’ duration, or when the duration is unknown: Warfarin anticoagulation (international normalized ratio [INR] 2-3) for at least 3 weeks before and 4 weeks after cardioversion, regardless of the CHA 2DS 2-VASc score and the cardioversion method (electrical or pharmacological) used ; anticoagulation with dabigatran, rivaroxaban, or apixaban is also reasonable
  • AF of ≥48 hours’ duration, or when the duration is unknown, requiring immediate cardioversion for hemodynamic instability: Anticoagulation should be administered as soon as possible and continued for 4 weeks after cardioversion
  • AF with high risk of stroke and <48 hours’ duration: Administration of IV heparin or low molecular weight heparin (LMWH), factor Xa inhibitor, or direct thrombin inhibitor as soon as possible before and immediately after cardioversion, followed by long-term anticoagulation therapy
  • AF with low risk of stroke and <48 hours’ duration: Administration of either IV heparin or LMWH, factor Xa or direct thrombin inhibitor or no antithrombotic therapy may be considered for cardioversion, without the need for postcardioversion oral anticoagulation therapy
  • For AF of any duration, long-term anticoagulation therapy should be based on the patient’s stroke risk profile
  • AF or atrial flutter of ≥48 hours’ duration: For conversion of AF of ≤7 days, agents with proven efficacy include flecainide, ibutilide, propafenone and, to a lesser degree, amiodarone
  • For conversion of AF lasting 7-90 days, agents with proven efficacy include amiodarone, ibutilide, flecainide, and propafenone
  • For conversion of AF lasting more than 90 days, oral propafenone, amiodarone, and dofetilide have been shown to be effective at converting persistent AF to normal sinus rhythm
  • Propafenone or flecainide in addition to a beta-blockers or non-dihydropyridine calcium channel antagonists is reasonable for termination of AF outside the hospital, once this treatment has been observed to be safe in a monitored setting for selected patients (“pill-in-the-pocket”)
  • Dofetilide therapy should not be initiated out of hospital because of the risk of torsade de pointes
  • Direct current cardioversion (DCC) is indicated when rapid ventricular rate does not respond promptly to medications in patients with AF and ongoing myocardial ischemia, hypotension or heart failure
  • Immediate DCC in preexcitation with rapid tachycardia or hemodynamic instability

NOTE: Repeated cardioversions may be undertaken in patients with persistent AF, provided that sinus rhythm can be maintained for a clinically meaningful period between cardioversion procedures; severity of AF symptoms and patient preference should be considered before initiation of a strategy requiring serial cardioversions

In general, the European Society of Cardiology (ESC) recommendations for cardioversion concur with the AHA/ACC/HRS guidelines. Many of the differences between the guidelines involve the use of vernakalant, which was approved for use in European Union in 2010 but has not been approved by the US Food and Drug Administration. Additional and/or variant ESC recommendations include the following [141] :

  • In the absence of structural heart disease, IV flecainide, propafenone, ibutilide, or vernakalant
  • In patients with risk factors for stroke or AF recurrence, oral anticoagulant therapy should be continued lifelong, irrespective of the apparent maintenance of sinus rhythm following cardioversion
  • In patients with AF ≤7 days and moderate structural heart disease, IV vernakalant may be considered
  • Vernakalant should be used with caution in patients with NYHA class I–II heart failure

The ESC guidelines note that vernakalant is contraindicated in patients with any of the following:

  • Hypotension (systolic blood pressure <100 mm Hg)
  • Recent (30 days) acute coronary syndrome
  • New York Heart Association (NYHA) class III and IV heart failure
  • Severe aortic stenosis
  • QT interval prolongation (uncorrected QT >440 ms)
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Maintaining Sinus Rhythm

The 2014 American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Rhythm Society (HRS) guidelines include the following recommendations for the prevention of atrial fibrillation (AF) and maintenance of sinus rhythm [1] :

  • Precipitating or reversible causes of AF should be treated before initiation of antiarrhythmic drug therapy; antiarrhythmic drug therapy can be considered for treatment of tachycardia-induced cardiomyopathy
  • Antiarrhythmic drugs include amiodarone, dofetilide, dronedarone, flecainide, propafenone, and sotalol; drug selection should be based on underlying heart disease and comorbidities
  • Consider risks, including proarrhythmia, before initiating antiarrhythmic drug treatment
  • Amiodarone should be used only after consideration of its potential toxicities and risks, and when other agents have failed or are contraindicated
  • Discontinue antiarrhythmic drugs, including dronedarone, when AF becomes permanent
  • Dronedarone is contraindicated for treatment of AF in patients with New York Heart Association (NYHA) class III and IV heart failure or patients who have had an episode of decompensated heart failure in the past 4 weeks

The European Society of Cardiology recommendations for maintenance of sinus rhythm are similar to those in the AHA/ACC/HRS. [141]

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Catheter Ablation

Both the 2014 American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Rhythm Society (HRS) and 2012 European Society of Cardiology updated guidelines suggest a more prominent role for radiofrequency ablation in the treatment of atrial fibrillation (AF), including its use as first-line therapy in recurrent symptomatic paroxysmal or persistent AF. [1, 141]

According to AHA/ACC/HRS guidelines, AF catheter ablation is contraindicated for patients who cannot be treated with anticoagulant therapy during and after the procedure and should not be performed with the sole intent of eliminating the need for anticoagulation. [1]

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