How to treat a patient with atrial fibrillation (AF) and normal blood pressure in an emergency setting?

Management of Atrial Fibrillation with Normal Blood Pressure in the Emergency Department

For hemodynamically stable AF patients with normal blood pressure in casualty, initiate rate control with IV beta-blockers or diltiazem as first-line therapy, while simultaneously assessing stroke risk and initiating appropriate anticoagulation. 1

Initial Assessment and Risk Stratification

Obtain a 12-lead ECG immediately to confirm AF and assess for pre-excitation patterns (delta waves suggesting WPW syndrome), as this fundamentally changes management. 1

Key clinical features to assess:

• Duration of AF episode: If >48 hours or unknown duration, cardioversion requires either 3 weeks of therapeutic anticoagulation first OR transesophageal echocardiography to exclude left atrial thrombus 1
• Symptoms: Palpitations, dyspnea, chest pain, or exertional intolerance indicate need for more aggressive rhythm control 2
• Underlying triggers: Check for thyroid dysfunction, electrolyte abnormalities, acute coronary syndrome, pulmonary disease, or alcohol intoxication 1, 3

Rate Control Strategy (First-Line for Stable Patients)

IV beta-blockers or diltiazem are the drugs of choice for acute rate control in hemodynamically stable AF patients with normal blood pressure. 1

Specific Agents:

• Beta-blockers (metoprolol, esmolol): Preferred in most patients, particularly those with suspected ACS or hyperthyroidism 1
• Diltiazem (nondihydropyridine calcium channel blocker): Equally effective alternative, particularly useful in patients with COPD or bronchospasm where beta-blockers are contraindicated 1
• Digoxin: Reserve for patients with heart failure and reduced ejection fraction (LVEF ≤40%), though onset is slower 1

Critical caveat: If wide-complex irregular rhythm is present, suspect pre-excited AF (WPW syndrome). Avoid all AV nodal blocking agents (beta-blockers, calcium channel blockers, digoxin, adenosine) as these can paradoxically accelerate ventricular response and cause hemodynamic collapse. 1

Anticoagulation Decision

Calculate CHA₂DS₂-VASc score immediately to determine stroke risk and anticoagulation need. 1, 2, 4

For AF Duration <48 Hours:

• Start therapeutic anticoagulation at presentation (low-molecular-weight heparin or unfractionated heparin at full treatment doses) if cardioversion is planned 1
• Continue anticoagulation for at least 4 weeks post-cardioversion regardless of whether sinus rhythm is maintained 1

For AF Duration >48 Hours or Unknown:

• Do NOT attempt cardioversion without either 3 weeks of therapeutic anticoagulation OR transesophageal echocardiography to exclude thrombus 1
• Initiate oral anticoagulation based on CHA₂DS₂-VASc score (≥2 in men, ≥3 in women warrants anticoagulation) 1, 2
• Direct oral anticoagulants (DOACs) are preferred over warfarin due to lower bleeding risk and no need for INR monitoring 1, 2

Rhythm Control Considerations

Elective cardioversion may be considered in select stable patients with AF <48 hours duration or after appropriate anticoagulation strategy. 1, 5

Pharmacologic Cardioversion Options (if no structural heart disease):

• IV flecainide or propafenone: Effective for recent-onset AF, but contraindicated in patients with severe LV hypertrophy, heart failure with reduced ejection fraction, or coronary artery disease 1
• IV vernakalant: Alternative for recent-onset AF, contraindicated in recent ACS, heart failure with reduced ejection fraction, or severe aortic stenosis 1
• IV amiodarone: Can be used when other agents are contraindicated, though slower onset; also provides rate control 1

Electrical Cardioversion:

• Synchronized cardioversion is appropriate for symptomatic patients with AF <48 hours or after appropriate anticoagulation 1
• Requires procedural sedation and post-cardioversion anticoagulation for minimum 4 weeks 1

Common Pitfalls to Avoid

• Never use AV nodal blockers in wide-complex irregular AF (suspect WPW) - this can be fatal 1
• Do not cardiovert AF >48 hours without anticoagulation or TEE unless patient is hemodynamically unstable 1
• Aspirin is NOT adequate for stroke prevention in AF - anticoagulation with warfarin or DOAC is required 2
• Do not discharge without addressing anticoagulation - this is the most important intervention for reducing morbidity and mortality 2
• Avoid digoxin as sole first-line rate control agent in acute setting due to slow onset of action 1, 3

Disposition

Admit patients with: new-onset AF requiring cardioversion, inadequate rate control despite treatment, significant underlying cardiac disease, or need for anticoagulation initiation with monitoring. 5, 4

Consider discharge with cardiology follow-up for patients with: well-controlled ventricular rate, known recurrent paroxysmal AF similar to prior episodes, appropriate anticoagulation initiated or already established, and reliable follow-up arranged. 5