What is the treatment for atrial fibrillation?

Treatment for Atrial Fibrillation

For most patients with atrial fibrillation, initiate rate control with beta-blockers or non-dihydropyridine calcium channel blockers (diltiazem, verapamil) as first-line therapy, combined with anticoagulation based on stroke risk assessment using the CHA₂DS₂-VASc score. 1, 2, 3

Initial Assessment

Before initiating treatment, confirm the diagnosis and assess critical factors:

• Obtain a 12-lead ECG to document atrial fibrillation, measure ventricular rate, and calculate the baseline QT interval 1, 3
• Assess hemodynamic stability immediately—if the patient has hypotension, acute heart failure, or ongoing chest pain, proceed directly to synchronized electrical cardioversion without delay 1, 2, 3
• Determine atrial fibrillation duration (onset <48 hours vs >48 hours vs unknown), as this dictates anticoagulation requirements before cardioversion 1, 3
• Obtain transthoracic echocardiogram to measure left ventricular ejection fraction (LVEF), assess for valvular disease, and measure left atrial size 1, 3
• Check thyroid function, renal function (calculate creatinine clearance), and hepatic function to identify reversible causes and guide medication dosing 1, 3

Stroke Prevention Strategy (Anticoagulation)

Calculate the CHA₂DS₂-VASc score immediately (Congestive heart failure=1, Hypertension=1, Age ≥75=2, Diabetes=1, Stroke/TIA=2, Vascular disease=1, Age 65-74=1, Sex category female=1) 1, 3

Anticoagulation Decision Algorithm:

• CHA₂DS₂-VASc score ≥2: Initiate oral anticoagulation (Class I recommendation) 1, 2, 3
• CHA₂DS₂-VASc score =1: Consider oral anticoagulation 2, 3
• CHA₂DS₂-VASc score =0 (males) or =1 (females with no other risk factors): No anticoagulation or aspirin 325 mg daily 1

Anticoagulant Selection:

Prefer direct oral anticoagulants (DOACs) over warfarin due to lower intracranial hemorrhage risk 1, 2, 3:

• Apixaban 5 mg twice daily, or 2.5 mg twice daily if patient meets ≥2 of these criteria: age ≥80 years, weight ≤60 kg, or creatinine ≥1.5 mg/dL 1, 3
• Alternative DOACs: dabigatran, edoxaban, or rivaroxaban at standard doses unless specific dose-reduction criteria are met 1

Use warfarin (INR target 2.0-3.0) only for:

• Mechanical heart valves 3
• Moderate-to-severe mitral stenosis 3
• Monitor INR weekly during initiation, then monthly when stable 1

Critical caveat: Continue anticoagulation based on stroke risk regardless of whether the patient is in atrial fibrillation or sinus rhythm—most strokes in trials occurred after anticoagulation was stopped or became subtherapeutic 1, 3

Rate Control Strategy (First-Line for Most Patients)

Rate control with chronic anticoagulation is the recommended initial strategy for the majority of patients, as the AFFIRM trial demonstrated no survival advantage with rhythm control and more hospitalizations and adverse drug effects in the rhythm control group 1, 3

Rate Control Medication Selection Based on LVEF:

For LVEF >40% (preserved ejection fraction):

• First-line options: Beta-blockers (metoprolol, atenolol) OR non-dihydropyridine calcium channel blockers (diltiazem 60-120 mg three times daily or 120-360 mg extended release; verapamil 40-120 mg three times daily or 120-480 mg extended release) 1, 2, 3
• Avoid diltiazem and verapamil in decompensated heart failure 3

For LVEF ≤40% (reduced ejection fraction):

• Use only beta-blockers and/or digoxin (0.0625-0.25 mg daily) 1, 2, 3
• Never use diltiazem or verapamil due to negative inotropic effects and risk of hemodynamic compromise 3

Rate Control Targets:

• Lenient rate control (resting heart rate <110 bpm) is acceptable initially unless symptoms persist 1, 2
• Strict rate control (resting heart rate <80 bpm) is reserved for patients with ongoing symptoms despite lenient control 1

Combination Therapy:

If monotherapy fails to achieve adequate rate control, combine digoxin with a beta-blocker or calcium channel blocker for better control at rest and during exercise 4, 1

Common pitfall: Digoxin as sole agent is ineffective in paroxysmal atrial fibrillation and should not be used as monotherapy in physically active patients 4, 1

Special Populations for Rate Control:

• Postoperative atrial fibrillation: Use beta-blocker or non-dihydropyridine calcium channel blocker; preoperative amiodarone reduces incidence in high-risk cardiac surgery 1
• High catecholamine states (acute illness, thyrotoxicosis): Prefer beta-blockers 1
• COPD or active bronchospasm: Use diltiazem or verapamil; avoid beta-blockers, sotalol, and propafenone 1
• Wolff-Parkinson-White syndrome with pre-excited atrial fibrillation: NEVER use AV nodal blockers (adenosine, digoxin, diltiazem, verapamil, beta-blockers, amiodarone) as they can accelerate ventricular rate and precipitate ventricular fibrillation 4, 1; if hemodynamically unstable, perform immediate DC cardioversion; if stable, use IV procainamide or ibutilide, then refer for catheter ablation of accessory pathway 1

Rhythm Control Strategy (Selected Patients)

Consider rhythm control for:

• Symptomatic patients despite adequate rate control 4, 1, 2, 3
• Younger patients with new-onset atrial fibrillation 2, 3
• Patients with rate-related cardiomyopathy (newly detected heart failure with rapid ventricular response) 1
• Hemodynamically unstable patients 1, 2, 3

Cardioversion Approach:

Immediate synchronized DC cardioversion for hemodynamic instability (hypotension, acute heart failure, ongoing chest pain) 1, 2, 3

Scheduled cardioversion for symptomatic patients after appropriate anticoagulation:

• If atrial fibrillation duration >48 hours or unknown: Anticoagulate therapeutically for at least 3 weeks before cardioversion, then continue for minimum 4 weeks after (longer if stroke risk factors present) 4, 1, 3
• If atrial fibrillation duration <48 hours: May proceed with cardioversion after initiating anticoagulation 1

Pharmacological Cardioversion Options:

• No structural heart disease: Flecainide or propafenone 4, 2, 5
• Structural heart disease or reduced LVEF: Amiodarone 2

Long-Term Antiarrhythmic Drug Selection

Selection is based strictly on cardiac structure and LVEF 4, 1, 3:

Algorithm for Antiarrhythmic Drug Selection:

No structural heart disease:

• First-line: Flecainide, propafenone, or sotalol 4, 1, 6
• These have relatively low toxicity risk 4, 1
• "Pill-in-the-pocket" approach may be used for infrequent, symptomatic episodes as an alternative to daily therapy 4, 6

Coronary artery disease with LVEF >35%:

• First-line: Sotalol (provides beta-blockade plus antiarrhythmic effect) 4, 1
• Second-line: Amiodarone 4, 1

Heart failure or LVEF ≤35%:

• Amiodarone is the only safe option due to proarrhythmic risk of other agents 4, 1, 3, 6
• Alternative: Dofetilide (requires in-hospital initiation with continuous monitoring) 4

Hypertension without left ventricular hypertrophy:

• Flecainide or propafenone may be used 4

Critical Safety Considerations for Antiarrhythmic Drugs:

Sotalol initiation requires hospitalization with continuous ECG monitoring for minimum 3 days 7:

• Baseline QT must be ≤450 msec to start therapy 7
• Monitor QT 2-4 hours after each dose 7
• Discontinue if QT ≥500 msec 7
• Dose based on creatinine clearance: 80 mg twice daily if CrCl >60 mL/min; 80 mg once daily if CrCl 40-60 mL/min; contraindicated if CrCl <40 mL/min 7

Propafenone and flecainide: When used for atrial fibrillation, always coadminister AV nodal blocking drugs to prevent 1:1 AV conduction during atrial flutter, which can cause dangerously rapid ventricular rates 4, 5

Catheter Ablation

Consider catheter ablation:

• Second-line when antiarrhythmic drugs fail to control symptoms 1, 2, 3
• First-line option in selected patients with paroxysmal atrial fibrillation 1, 2

AV node ablation with pacemaker implantation is reserved for patients unresponsive to or ineligible for intensive rate and rhythm control therapy 2

Ongoing Management

• Monitor renal function at least annually with DOACs, more frequently if clinically indicated 1, 3
• Reassess therapy periodically and evaluate for new modifiable risk factors 1, 3
• Manage comorbidities aggressively: hypertension, heart failure, diabetes, obesity, obstructive sleep apnea, alcohol intake 1, 2, 3
• Never discontinue anticoagulation based on rhythm status—base the decision solely on stroke risk 1, 3