What is the recommended management for atrial fibrillation (AF), including diagnosis with electrocardiogram (ECG), anticoagulation based on CHA₂DS₂‑VASc score, rhythm versus rate control strategies, and treatment of reversible precipitants?

Management of Atrial Fibrillation

Immediate Assessment and Stabilization

If the patient presents with hemodynamic instability (hypotension, acute heart failure, ongoing chest pain, altered mental status, shock, or pulmonary edema), perform immediate synchronized electrical cardioversion at 120-200 joules biphasic without waiting for anticoagulation. 1 Administer intravenous heparin bolus concurrently if feasible. 2, 1

For hemodynamically stable patients, confirm the diagnosis with a 12-lead ECG documenting the irregular rhythm and absence of P waves. 2, 1 Assess ventricular rate, QRS duration, and QT interval on the ECG. 1

Stroke Risk Assessment and Anticoagulation

Calculate the CHA₂DS₂-VASc score immediately: Congestive heart failure (1 point), Hypertension (1 point), Age ≥75 years (2 points), Diabetes (1 point), Prior Stroke/TIA/thromboembolism (2 points), Vascular disease (1 point), Age 65-74 years (1 point), Sex category female (1 point). 2, 1

Initiate oral anticoagulation for all patients with CHA₂DS₂-VASc score ≥2 in men or ≥3 in women. 2 Consider anticoagulation for score of 1 in men or 2 in women based on individual bleeding risk and patient preference. 2

Prescribe direct oral anticoagulants (DOACs)—apixaban, dabigatran, edoxaban, or rivaroxaban—as first-line therapy over warfarin, except in patients with mechanical heart valves or moderate-to-severe mitral stenosis. 2, 1, 3 DOACs have lower intracranial hemorrhage risk compared to warfarin. 3

• Apixaban: 5 mg twice daily (or 2.5 mg twice daily if patient meets ≥2 of: age ≥80 years, weight ≤60 kg, creatinine ≥1.5 mg/dL) 3
• If warfarin is used, maintain INR 2.0-3.0 with weekly monitoring during initiation and monthly when stable 2, 3

Do not combine anticoagulants with antiplatelet agents unless there is an acute vascular event or specific procedural indication—this increases bleeding risk without additional stroke benefit. 1, 3

Rate Control Strategy

For patients with LVEF >40% (preserved ejection fraction), administer intravenous beta-blockers (metoprolol 2.5-5 mg IV bolus over 2 minutes, repeat every 5-10 minutes up to 15 mg total) or non-dihydropyridine calcium channel blockers (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) as first-line therapy. 2, 1, 3

For patients with LVEF ≤40% or heart failure, use only beta-blockers (bisoprolol, carvedilol, long-acting metoprolol) and/or digoxin—avoid calcium channel blockers due to negative inotropic effects. 2, 1, 3

Target initial heart rate <110 beats per minute (lenient rate control) for most patients. 2, 1, 3 Pursue stricter control (<80 bpm) only if symptoms persist despite lenient control. 2, 3

If monotherapy fails, combine digoxin with a beta-blocker or calcium channel blocker for better control at rest and during exercise, but monitor closely for bradycardia. 2, 1, 3

Special Populations for Rate Control

• COPD or active bronchospasm: Use non-dihydropyridine calcium channel blockers (diltiazem 60-120 mg PO TID or verapamil 40-120 mg PO TID); avoid beta-blockers 2, 1, 3
• Thyrotoxicosis: Beta-blockers are preferred to control ventricular response 1, 3
• Wolff-Parkinson-White with pre-excited AF: If unstable, immediate cardioversion; if stable, IV procainamide or ibutilide. Never use AV nodal blockers (adenosine, beta-blockers, calcium channel blockers, digoxin, amiodarone) as they can accelerate ventricular rate and precipitate ventricular fibrillation. 1, 3 Catheter ablation of accessory pathway is definitive treatment. 1, 3

Critical pitfall: Do not use digoxin as sole agent for rate control in paroxysmal AF—it is ineffective during exercise and sympathetic surge. 2, 1, 4

Rhythm Control Considerations

Consider rhythm control strategy for: symptomatic patients despite adequate rate control, younger patients (<65 years), new-onset AF (<48 hours), patients with heart failure with reduced ejection fraction (HFrEF), or those with rate-related cardiomyopathy. 2, 1, 3

Cardioversion Timing and Anticoagulation

For AF duration >48 hours or unknown duration, provide therapeutic anticoagulation for ≥3 weeks before elective cardioversion, then continue for minimum 4 weeks after cardioversion. 2, 1, 3 Alternatively, perform transesophageal echocardiography to exclude left atrial thrombus; if negative, proceed with cardioversion after initiating heparin. 2, 1

For AF duration <48 hours with CHA₂DS₂-VASc score ≥2, initiate anticoagulation before cardioversion as left atrial thrombus has been detected in up to 14% of patients with short-duration AF. 3

Continue anticoagulation long-term based on CHA₂DS₂-VASc score regardless of whether cardioversion was successful—most strokes occur after anticoagulation is stopped or when INR is subtherapeutic. 3

Antiarrhythmic Drug Selection Algorithm

The choice of antiarrhythmic drug is determined strictly by cardiac structure and LVEF: 2, 1, 3

1. No structural heart disease (normal LVEF, no CAD, no LVH): Flecainide, propafenone, or sotalol as first-line 2, 1, 3

   • Flecainide: 200-300 mg PO or 1.5-2 mg/kg IV over 10 minutes 3
   • Propafenone: 450-600 mg PO or 1.5-2 mg/kg IV over 10 minutes 3
   • Outpatient initiation acceptable if well-tolerated 2

2. Coronary artery disease with LVEF >35%: Sotalol first-line (requires hospitalization with continuous ECG monitoring for minimum 3 days, dose based on creatinine clearance) 2, 1, 3

3. Heart failure or LVEF ≤40%: Amiodarone or dofetilide are the only safe options due to proarrhythmic risk of other agents 2, 1, 3

   • Amiodarone: 5-7 mg/kg IV over 1-2 hours, then 50 mg/hour infusion (max 1 g/24 hours); conversion may take 8-12 hours 3

4. Hypertrophic cardiomyopathy: Amiodarone or disopyramide combined with beta-blocker or non-dihydropyridine calcium channel antagonist; anticoagulation mandatory regardless of CHA₂DS₂-VASc score 2

"Pill-in-the-pocket" approach: Selected patients with infrequent symptomatic paroxysmal AF and no structural heart disease may self-administer single oral dose of flecainide (200-300 mg) or propafenone (450-600 mg) at home after safety confirmed in supervised hospital setting. 3

Initial Diagnostic Workup

Obtain transthoracic echocardiogram to assess left atrial size, left ventricular function, valvular disease, and exclude structural abnormalities. 2, 1, 3

Order blood tests: thyroid function (TSH), renal function (creatinine clearance), hepatic function, electrolytes (correct hypokalemia before initiating antiarrhythmics), complete blood count. 1, 3

Assess for reversible precipitants: hyperthyroidism, acute alcohol intoxication, pulmonary embolism, myocardial infarction, pericarditis, myocarditis, hypertensive crisis, obstructive sleep apnea. 2, 3

Management of Permanent AF

For permanent AF (when patient and physician agree no further rhythm restoration attempts will be made), focus exclusively on rate control and anticoagulation with no rhythm control interventions. 2, 3

Target resting heart rate <110 bpm (lenient control), with stricter control only if symptoms persist. 2, 3 If pharmacological rate control fails despite maximal therapy, consider AV node ablation with pacemaker implantation. 2, 3 In severely symptomatic patients with permanent AF and heart failure hospitalization, AV node ablation combined with cardiac resynchronization therapy is reasonable. 2, 3

Catheter Ablation

Catheter ablation is recommended as first-line therapy in symptomatic patients with paroxysmal AF to improve symptoms and slow progression to persistent AF. 5 It is also first-line for patients with AF and HFrEF to improve quality of life, left ventricular systolic function, and reduce mortality and heart failure hospitalization. 5

Catheter ablation is second-line after failed antiarrhythmic drug therapy in persistent AF or when patients are unable/unwilling to take medications long-term. 2, 1, 3

Comorbidity Management

Aggressively manage modifiable risk factors to prevent AF recurrence and progression: 2, 3

• Hypertension: Target BP <140/90 mmHg (stricter if tolerated) 2
• Obesity: Weight loss of ≥10% body weight reduces AF burden 2
• Obstructive sleep apnea: CPAP therapy 2, 3
• Diabetes: Optimize glycemic control 2
• Alcohol: Reduce or eliminate intake 2
• Physical activity: Regular moderate exercise 2

Common Pitfalls to Avoid

• Do not delay cardioversion for anticoagulation in truly unstable patients—hemodynamic instability takes precedence 1
• Do not use flecainide or propafenone in patients with coronary artery disease or structural heart disease—high proarrhythmic risk 3
• Do not perform catheter ablation without prior medical therapy trial except in selected paroxysmal AF or HFrEF patients 2, 3
• Do not discontinue anticoagulation after successful cardioversion if stroke risk factors persist—base decision on CHA₂DS₂-VASc score, not rhythm status 3
• Do not combine beta-blockers with diltiazem or verapamil except under specialist supervision with ambulatory ECG monitoring for bradycardia 2