Fibrillation Management

Initial Assessment and Diagnostic Confirmation

The American College of Cardiology recommends confirming the diagnosis with a 12-lead ECG showing absolutely irregular RR intervals, absence of distinct P waves, and atrial cycle (when visible) generally <200 ms 2, 3
Immediate assessment of hemodynamic stability is crucial, looking for signs of hypoperfusion, decompensated heart failure, frequency-related cardiac ischemia, or neurological symptoms that may indicate stroke 1, 4
Differentiate from other arrhythmias: atrial flutter shows regular "sawtooth" F waves; atrial tachycardias have distinct P waves with an isoelectric line between them 2, 5

For hemodynamically stable patients, frequency control is the initial approach: beta blockers (e.g., metoprolol 2.5-5 mg in 2 minutes) or non-dihydropyridine calcium channel blockers (e.g., diltiazem) are the drugs of choice for acute control of ventricular frequency (Class IIa, Level of Evidence A) 4, 1
Target heart rate: 80-110 bpm at rest 1
Digoxin and amiodarone may be used in patients with congestive heart failure, but consider the potential risk of conversion to sinus rhythm with amiodarone 4

The American Heart Association recommends calculating the stroke risk using the CHA₂DS₂-VASc score (points for age, sex, hypertension, diabetes, previous stroke, vascular disease, heart failure) 1, 4
Oral anticoagulation with a vitamin K antagonist or direct oral anticoagulant is recommended for patients with an estimated stroke risk ≥2% per year (Class I, Level A) 1, 4

The American College of Cardiology recommends cardioversion be approached with caution due to the risk of thromboembolism: cardioversion is indicated immediately in hemodynamically unstable patients (hypotension, acute pulmonary edema, myocardial ischemia, shock) 4
Cardioversion is contraindicated in patients with atrial fibrillation >48 hours without adequate anticoagulation due to the increased risk of cardioembolic events 4, 1
Alternative strategy: perform cardioversion after anticoagulation with heparin and transesophageal echocardiogram to ensure absence of left atrial thrombus 4
Therapeutic anticoagulation for at least 3 weeks before cardioversion is recommended for patients with known atrial fibrillation >48 hours 1
Anticoagulation should continue indefinitely after cardioversion in patients with high stroke risk 1