What is the initial management for a patient with atrial fibrillation (AF) in the Emergency Department (ED)?

Initial Management of Atrial Fibrillation in the Emergency Department

For patients presenting with atrial fibrillation in the ED, immediately assess hemodynamic stability and proceed with synchronized electrical cardioversion (120-200 joules biphasic) if the patient shows signs of instability including hypotension, ongoing chest pain, altered mental status, shock, or pulmonary edema—do not delay for anticoagulation in truly unstable patients. 1

Immediate Assessment

Upon presentation, the following must be rapidly evaluated:

• Document the arrhythmia with at least a single-lead ECG to confirm AF, assess ventricular rate, QRS duration, and QT interval 1
• Assess for hemodynamic instability: hypotension, ongoing chest pain/ischemia, altered mental status, shock, or pulmonary edema 1
• Determine AF duration (<48 hours vs >48 hours vs unknown), as this critically impacts cardioversion and anticoagulation decisions 1
• Evaluate for underlying precipitants: thyroid disease, acute illness, post-operative state, or heart failure 2

Hemodynamically Unstable Patients

If any signs of instability are present, perform immediate synchronized electrical cardioversion without waiting for anticoagulation. 1 Administer procedural sedation, deliver 120-200 joules biphasic (or 200 joules monophasic), and give concurrent intravenous unfractionated heparin bolus followed by continuous infusion if AF duration exceeds 48 hours or is unknown 1

Hemodynamically Stable Patients: Rate Control Strategy

For stable patients, rate control is the initial priority and should be achieved before considering rhythm control. 2, 3

Rate Control Medication Selection

The choice of rate control agent depends on left ventricular ejection fraction (LVEF):

For patients with LVEF >40% (preserved ejection fraction):

• First-line: Intravenous beta-blockers (metoprolol preferred) or non-dihydropyridine calcium channel blockers (diltiazem or verapamil) 1
  • Metoprolol: 2.5-5 mg IV bolus over 2 minutes, repeat every 5-10 minutes up to 15 mg total 1
  • Diltiazem: 0.25 mg/kg IV bolus over 2 minutes, followed by 0.35 mg/kg if needed, then continuous infusion 5-15 mg/hour 1
• These agents provide rapid onset and effectiveness even during high sympathetic tone 3

For patients with LVEF ≤40% (reduced ejection fraction or heart failure):

• Use beta-blockers and/or digoxin only—avoid diltiazem and verapamil due to negative inotropic effects and risk of worsening hemodynamic compromise 2, 3, 1
• Digoxin: 0.0625-0.25 mg per day 2
• Intravenous amiodarone (300 mg IV diluted in 250 ml of 5% glucose over 30-60 minutes) may be considered for acute rate control in heart failure 2

Target initial heart rate <110 beats per minute (lenient rate control) as the initial goal, reserving stricter control (<80 bpm resting) for patients with persistent symptoms despite lenient control 1, 2

Special Populations

For patients with COPD or active bronchospasm:

• Avoid beta-blockers, sotalol, and propafenone 2
• Use non-dihydropyridine calcium channel blockers (diltiazem 60-120 mg PO TDS or verapamil 40-120 mg PO TDS) as first-line 2

For patients with Wolff-Parkinson-White syndrome and pre-excited AF:

• Do NOT use AV nodal blockers (adenosine, digoxin, diltiazem, verapamil, beta-blockers, or amiodarone) as they can accelerate ventricular rate and precipitate ventricular fibrillation 2
• If hemodynamically unstable: immediate DC cardioversion 2
• If stable: IV procainamide or ibutilide 2
• Definitive treatment: catheter ablation of accessory pathway 2

For high catecholamine states (acute illness, post-operative, thyrotoxicosis):

• Beta-blockers are preferred 2

Anticoagulation and Stroke Risk Assessment

Calculate CHA₂DS₂-VASc score immediately to guide anticoagulation decisions 2, 1:

• Congestive heart failure: 1 point
• Hypertension: 1 point
• Age ≥75 years: 2 points
• Diabetes mellitus: 1 point
• Stroke/TIA/thromboembolism history: 2 points
• Vascular disease: 1 point
• Age 65-74 years: 1 point
• Sex category (female): 1 point

Initiate anticoagulation for all eligible patients with CHA₂DS₂-VASc score ≥2 (or consider for score of 1). 1, 2

Direct oral anticoagulants (DOACs)—apixaban, dabigatran, edoxaban, or rivaroxaban—are preferred over warfarin except in patients with mechanical heart valves or mitral stenosis 2, 1

For apixaban: 5 mg twice daily (or 2.5 mg twice daily if patient meets dose-reduction criteria: age ≥80 years, weight ≤60 kg, or creatinine ≥1.5 mg/dL—any 2 of these 3 factors) 2

For warfarin: target INR 2.0-3.0 with weekly monitoring during initiation, then monthly when stable 4, 2

Rhythm Control Considerations

Consider rhythm control for:

• Symptomatic patients despite adequate rate control 2, 3
• Younger patients (<65 years) with new-onset AF 1
• Patients with rate-related cardiomyopathy (newly detected heart failure with rapid ventricular response) 2
• First episode of AF in patients where restoration of sinus rhythm is desired 5

Cardioversion Timing and Anticoagulation

For AF duration <48 hours:

• Cardioversion may proceed after initiating anticoagulation without waiting for therapeutic levels 1

For AF duration >48 hours or unknown duration:

• Provide therapeutic anticoagulation for 3 weeks before elective cardioversion, then continue anticoagulation for minimum 4 weeks after cardioversion 1, 5
• Continue long-term anticoagulation based on CHA₂DS₂-VASc score regardless of whether sinus rhythm is maintained 2

Pharmacological Cardioversion Options

For patients without structural heart disease:

• Flecainide or propafenone 3, 5

For patients with structural heart disease or reduced ejection fraction:

• Amiodarone 3

Initial Diagnostic Workup

Before discharge or admission, obtain:

• Transthoracic echocardiogram to assess left atrial size, left ventricular function, valvular disease, and exclude structural abnormalities 2, 1
• Blood tests: thyroid function (TSH), renal function (creatinine clearance), hepatic function, and electrolytes 2, 1
• Chest X-ray to assess for pulmonary edema or underlying lung disease 2

Critical Pitfalls to Avoid

• Do not delay cardioversion for anticoagulation in truly unstable patients—hemodynamic instability takes precedence 1
• Do not use digoxin as sole agent for rate control in paroxysmal AF or physically active patients—it is ineffective during exercise and sympathetic surge 1, 2
• Do not use AV nodal blockers in Wolff-Parkinson-White syndrome with pre-excited AF—this can precipitate ventricular fibrillation 2
• Do not combine anticoagulants with antiplatelet agents unless acute vascular event or specific procedural indication—this increases bleeding risk without additional benefit 1
• Do not discontinue anticoagulation after successful cardioversion if stroke risk factors persist—most strokes occur after anticoagulation is stopped or when INR is subtherapeutic 2
• Do not use calcium channel blockers (diltiazem, verapamil) in patients with reduced ejection fraction or decompensated heart failure 2, 3

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 2, 1 Monitor closely for bradycardia when using combination therapy 3