What is the management of atrial fibrillation, including medication doses?

Management of Atrial Fibrillation Including Medication Doses

For rate control in atrial fibrillation, use beta-blockers or nondihydropyridine calcium channel antagonists as first-line therapy, with specific dosing based on acuity and patient characteristics. 1

Rate Control Strategy

Acute Setting (IV Administration)

For hemodynamically stable patients requiring rapid rate control:

• Metoprolol tartrate: 2.5-5 mg IV bolus over 2 minutes; may repeat up to 3 doses 1
• Diltiazem: 0.25 mg/kg IV bolus over 2 minutes, may repeat 0.35 mg/kg after 15 minutes if needed, then 5-15 mg/hour continuous infusion 1, 2
• Verapamil: 5-10 mg IV over ≥2 minutes (may repeat twice), then 5 mg/hour continuous infusion (maximum 20 mg/hour) 1
• Esmolol: 500 mcg/kg IV bolus over 1 minute, then 50-300 mcg/kg/minute infusion 1

For hemodynamically unstable patients, electrical cardioversion is indicated immediately rather than pharmacological rate control. 1

In critically ill patients or those with heart failure without pre-excitation:

• Amiodarone: 150-300 mg IV over 1 hour, then 10-50 mg/hour over 24 hours 1
• Digoxin: 0.25-0.5 mg IV over several minutes; repeat doses of 0.25 mg every 2 hours up to maximum 1.5 mg over 24 hours 1

Chronic Oral Maintenance Therapy

Target heart rate: <80 bpm (strict control) for symptomatic patients or <110 bpm (lenient control) for asymptomatic patients with preserved left ventricular function. 1

Beta-blockers (first-line):

• Metoprolol succinate: 50-400 mg once daily 1
• Metoprolol tartrate: 25-200 mg twice daily 1
• Atenolol: 25-100 mg once daily 1
• Bisoprolol: 2.5-10 mg once daily 1
• Carvedilol: 3.125-25 mg twice daily 1
• Propranolol: 10-40 mg three to four times daily 1
• Nadolol: 10-240 mg once daily 1

Nondihydropyridine calcium channel blockers (avoid in heart failure with reduced ejection fraction):

• Diltiazem extended-release: 120-360 mg once daily 1
• Verapamil extended-release: 180-480 mg once daily 1

Digoxin (for sedentary patients, elderly ≥80 years, or as adjunct therapy):

• Maintenance dose: 0.0625-0.25 mg once daily 1
• Monitor plasma concentrations; increased mortality occurs at levels exceeding 1.2 ng/mL 1

Amiodarone (when other measures unsuccessful or contraindicated):

• Loading: 6-10 grams over 2-4 weeks (can combine IV and oral) 1
• Maintenance: 100-200 mg once daily 1

Combination Therapy

When monotherapy fails to achieve adequate rate control at rest and during exercise, combine digoxin with either a beta-blocker or nondihydropyridine calcium channel antagonist, modulating doses to avoid bradycardia. 1

Critical Contraindications

Do NOT use the following in specific scenarios:

• Nondihydropyridine calcium channel antagonists in decompensated heart failure (may exacerbate hemodynamic compromise) 1
• Digoxin, nondihydropyridine calcium channel antagonists, or amiodarone in pre-excitation syndromes (e.g., Wolff-Parkinson-White) as they may paradoxically accelerate ventricular response 1
• Dronedarone for rate control in permanent AF 1
• Digoxin as sole agent in paroxysmal AF (ineffective for rate control during activity) 1

Anticoagulation for Stroke Prevention

All patients with AF require stroke risk assessment and appropriate anticoagulation unless contraindicated. 1

For patients with estimated stroke risk ≥2% per year:

• Direct oral anticoagulants (DOACs) preferred over warfarin due to lower bleeding risk: 3, 4, 5

  • Apixaban: 5 mg twice daily (reduce to 2.5 mg twice daily if ≥2 of: age ≥80 years, weight ≤60 kg, serum creatinine ≥1.5 mg/dL) 3
  • Rivaroxaban: 20 mg once daily with food (15 mg once daily if CrCl 15-50 mL/min) 4
  • Edoxaban: dosing based on renal function 5

• Warfarin: Target INR 2.0-3.0 if DOACs contraindicated 1

DOACs reduce stroke risk by 60-80% compared with placebo and have superior safety profile compared with warfarin. 5

Cardioversion Anticoagulation Protocol

For AF duration ≥48 hours or unknown duration:

• Anticoagulate for at least 3 weeks prior to cardioversion and continue for at least 4 weeks after 1
• Alternative: Perform transesophageal echocardiogram to exclude left atrial thrombus, then cardiovert with anticoagulation maintained for ≥4 weeks 1

For AF duration <48 hours with high stroke risk:

• Administer IV heparin, LMWH, or factor Xa/direct thrombin inhibitor before or immediately after cardioversion, followed by long-term anticoagulation 1

Rhythm Control Considerations

Early rhythm control with antiarrhythmic drugs or catheter ablation is recommended for:

• Symptomatic paroxysmal AF to improve symptoms and slow progression 5
• Heart failure with reduced ejection fraction to improve quality of life, left ventricular function, and reduce mortality/hospitalization 5

Catheter ablation is first-line therapy in symptomatic paroxysmal AF and should be considered before AV nodal ablation. 6, 5

Monitoring Requirements

Assess heart rate control during exercise, not just at rest, adjusting pharmacological treatment to keep rate in physiological range. 1

For antiarrhythmic drugs requiring monitoring:

• Dofetilide/Sotalol: Continuous ECG monitoring during initiation, serum creatinine for CrCl estimation, serum potassium/magnesium every 3-6 months 1
• Dronedarone: AST/ALT within first 6 months 1
• Amiodarone: Baseline and periodic thyroid function, liver function, pulmonary function, ophthalmologic examination 1

AV Nodal Ablation

AV nodal ablation with permanent pacemaker is reasonable when pharmacological management is inadequate and rhythm control is not achievable, but should NOT be performed without prior attempts at medical rate control. 1, 6