What is the emergency department (ED) workup for new onset atrial fibrillation (A fib)?

From the Guidelines

The emergency department workup for new onset atrial fibrillation should prioritize a thorough assessment of hemodynamic stability, identification of underlying causes, and appropriate management strategies, as outlined in the 2024 ESC guidelines for the management of atrial fibrillation 1. Begin with a complete history and physical examination, focusing on symptoms, duration, and potential triggers. Obtain a 12-lead ECG to confirm atrial fibrillation and assess for other abnormalities, such as LV hypertrophy, P-wave duration and morphology or fibrillatory waves, pre-excitation, bundle-branch block, and prior MI, as recommended in the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation 1. Laboratory tests should include complete blood count, comprehensive metabolic panel, thyroid function tests, and cardiac biomarkers, as well as blood tests of thyroid, renal, and hepatic function, as suggested in the 2003 American College of Cardiology/American Heart Association clinical practice guidelines 1. Chest X-ray can identify pulmonary pathology, and a bedside echocardiogram may reveal structural heart disease, such as valvular heart disease, left and right atrial size, LV size and function, and peak RV pressure (pulmonary hypertension) 1. For hemodynamically unstable patients (hypotensive, altered mental status, chest pain, or heart failure), immediate synchronized cardioversion at 120-200 joules is indicated. For stable patients, rate control is typically achieved with beta-blockers (metoprolol 5mg IV every 5 minutes up to 15mg) or calcium channel blockers (diltiazem 0.25mg/kg IV over 2 minutes, followed by 0.35mg/kg if needed). Anticoagulation should be considered based on CHA₂DS₂-VASc score, with heparin or direct oral anticoagulants initiated if the score is ≥2 for men or ≥3 for women. For patients with onset <48 hours, cardioversion may be attempted after rate control, typically with amiodarone 150mg IV over 10 minutes, followed by 1mg/min for 6 hours, then 0.5mg/min. Cardiology consultation is recommended for complex cases or if considering electrical cardioversion. Key considerations in the management of atrial fibrillation include:

• Comorbidity and risk factor management
• Avoiding stroke and thromboembolism
• Reducing symptoms through rate and rhythm control
• Evaluation and dynamic reassessment
• Patient empowerment and education
• A patient-centered, shared decision-making approach to management.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

ED Workup for New Onset Atrial Fibrillation

• The management of new-onset atrial fibrillation (AF) in the emergency department (ED) is crucial, as it is the most common tachyarrhythmia managed in the ED 2.
• Recent-onset AF, defined as symptom onset less than 48 hours, is a common ED presentation, and treatment modalities may include rate control or acute electrical or pharmacological cardioversion 2.
• Patients with new-onset AF have an increased risk of stroke and systemic thromboembolism, and anticoagulation therapy is often necessary 3.
• A study found that almost half of patients with new-onset AF who presented to the ED and were indicated for anticoagulation therapy were discharged without it 3.

Predictive Factors for Early Successful Cardioversion

• Factors associated with early conversion to sinus rhythm in patients with new-onset AF include age younger than 65 years and symptom duration of less than 48 hours 4.
• The presence of signs of heart failure is significantly associated with unsuccessful early cardioversion 4.
• Patients with new-onset AF who are young, have a short duration of symptoms, and do not have signs of heart failure can be managed in the ED observation unit, avoiding longer hospitalization 4.

Management of Atrial Fibrillation in the ED

• Several treatment protocols have been developed to improve the efficiency of AF management in the ED, including initiation of oral anticoagulant therapy, cardioversion, and arranging for outpatient follow-up 5.
• Published treatment protocols for AF in the ED have been shown to reduce unnecessary hospital admissions and improve adherence to guideline-directed oral anticoagulant therapy 5.
• The European Society of Cardiology 2024 guidelines provide detailed recommendations for the management of new-onset AF, and synthetic and practical summaries of these guidelines are available 6.