What is the treatment plan for Atrial Fibrillation (Afib)?

Atrial Fibrillation Assessment and Treatment Plan

Initial Assessment

Confirm AF diagnosis with ECG, obtain transthoracic echocardiogram to assess left ventricular ejection fraction (LVEF), valvular disease, and left atrial size, and check thyroid, renal, and hepatic function to identify reversible causes. 1

• Assess for hemodynamic instability (hypotension, acute heart failure, ongoing chest pain) requiring immediate electrical cardioversion 2, 1
• Determine AF duration (<48 hours vs >48 hours or unknown) as this dictates cardioversion anticoagulation requirements 2, 1
• Calculate CHA₂DS₂-VASc score immediately to guide anticoagulation decisions 1, 3
• Evaluate for underlying conditions: hypertension, heart failure, diabetes, obesity, obstructive sleep apnea, and alcohol intake 1

Anticoagulation Strategy (Priority #1)

Initiate direct oral anticoagulants (DOACs) such as apixaban, dabigatran, edoxaban, or rivaroxaban over warfarin for all patients with CHA₂DS₂-VASc score ≥2, and consider for score ≥1. 2, 1, 3

• DOACs are preferred due to lower intracranial hemorrhage risk compared to vitamin K antagonists 1
• Use warfarin only for mechanical heart valves or moderate-to-severe mitral stenosis, targeting INR 2.0-3.0 2, 4
• For apixaban: 5 mg twice daily, or 2.5 mg twice daily if patient meets ≥2 of these criteria: age ≥80 years, weight ≤60 kg, creatinine ≥1.5 mg/dL 1
• Continue anticoagulation regardless of rhythm status (sinus rhythm vs AF) based on stroke risk, not current rhythm 1, 3
• Assess and manage modifiable bleeding risk factors, but do not use bleeding risk scores to withhold anticoagulation 2, 1
• Do not add antiplatelet therapy to anticoagulation for stroke prevention 2

Cardioversion Anticoagulation Requirements

• If AF duration >48 hours or unknown: therapeutic anticoagulation for ≥3 weeks before cardioversion, continue ≥4 weeks after 2, 1
• If AF duration <48 hours: may proceed with cardioversion after initiating anticoagulation 1
• Alternative: perform transesophageal echocardiography to exclude thrombus if unable to wait 3 weeks 2

Rate Control Strategy (Initial Approach for Most Patients)

Beta-blockers, diltiazem, or verapamil are first-line for rate control in patients with LVEF >40%; beta-blockers and/or digoxin are first-line for LVEF ≤40%. 2, 1, 3

For LVEF >40% (Preserved Function)

• First-line options: metoprolol, esmolol, diltiazem, or verapamil 2, 1
• Diltiazem: 60-120 mg PO three times daily (or 120-360 mg extended release) 1
• Verapamil: 40-120 mg PO three times daily (or 120-480 mg extended release) 1
• Avoid diltiazem and verapamil in decompensated heart failure 5

For LVEF ≤40% (Reduced Function)

• Use only beta-blockers and/or digoxin 2, 1, 3
• Digoxin: 0.0625-0.25 mg daily 1
• Never use diltiazem or verapamil in heart failure with reduced ejection fraction 5

Rate Control Targets

• Initial target: resting heart rate <110 bpm (lenient control) 1, 3, 5
• Stricter control (<80 bpm) only if symptoms persist with lenient approach 1, 3
• Lenient control is non-inferior to strict control for mortality, heart failure hospitalization, and stroke 5

Combination Therapy

• If monotherapy inadequate: combine digoxin with beta-blocker or calcium channel blocker for better control at rest and during exercise 1, 5
• Do not use digoxin as sole agent in paroxysmal AF 1

Acute Rate Control (Hemodynamically Stable)

• IV metoprolol, esmolol, diltiazem, or verapamil for rapid ventricular rate control 1, 5
• Diltiazem achieves rate control faster than metoprolol 5
• For hemodynamic instability: IV amiodarone or esmolol 1

Special Populations

• COPD/active bronchospasm: use diltiazem or verapamil; avoid beta-blockers 1
• Wolff-Parkinson-White with pre-excited AF: immediate DC cardioversion if unstable; IV procainamide if stable; never use AV nodal blockers (beta-blockers, calcium channel blockers, digoxin, adenosine, amiodarone) as they can precipitate ventricular fibrillation 1
• Post-operative AF: beta-blocker or non-dihydropyridine calcium channel blocker; preoperative amiodarone reduces incidence in high-risk cardiac surgery 1

Rhythm Control Strategy (Selected Patients)

Consider rhythm control for symptomatic patients despite adequate rate control, younger patients, new-onset AF, or those with hemodynamic instability. 1, 3

Electrical Cardioversion

• Immediate synchronized DC cardioversion for hemodynamic instability (hypotension, acute heart failure, ongoing ischemia) 2, 1, 3
• Scheduled cardioversion for symptomatic patients after appropriate anticoagulation 2, 1

Pharmacological Cardioversion

For patients without structural heart disease: IV flecainide or propafenone 2, 1

For patients with structural heart disease, coronary artery disease, or LVEF ≤40%: IV amiodarone (300 mg IV diluted in 250 mL 5% glucose over 30-60 minutes) 2, 1

• IV vernakalant for recent-onset AF, excluding recent ACS, heart failure with reduced ejection fraction, or severe aortic stenosis 2
• Do not use flecainide, propafenone, or sotalol in patients with severe left ventricular hypertrophy, heart failure with reduced ejection fraction, or coronary artery disease 2

Long-term Antiarrhythmic Drugs

Selection based on cardiac structure: 1

• No structural heart disease: flecainide, propafenone, or sotalol 1, 6
• Coronary artery disease with LVEF >35%: sotalol or amiodarone 1
• LVEF ≤35% or heart failure: amiodarone only 1, 6
• Hypertension without left ventricular hypertrophy: flecainide or propafenone 1

Catheter Ablation

• Consider as second-line therapy when antiarrhythmic drugs fail to control symptoms 1, 3
• Consider as first-line in selected patients with paroxysmal AF 1, 3
• For refractory cases: AV node ablation with pacemaker implantation 3

Evidence-Based Treatment Approach

Rate control is the preferred initial strategy for most patients, as the AFFIRM trial demonstrated no survival advantage with rhythm control and more hospitalizations and adverse drug effects in the rhythm control group. 1, 3, 7

• Beta-blockers were most effective for rate control in AFFIRM, achieving adequate control in 70% of patients 7
• Rhythm control should be reserved for symptomatic patients despite adequate rate control, younger patients, or new-onset AF 1, 3
• Anticoagulation must continue based on stroke risk regardless of rhythm strategy, as most strokes occur after anticoagulation is stopped or subtherapeutic 1

Common Pitfalls to Avoid

• Never discontinue anticoagulation after successful cardioversion or ablation if stroke risk factors persist 1, 3
• Never use bleeding risk scores to withhold anticoagulation 2, 1
• Never use AV nodal blockers in Wolff-Parkinson-White with pre-excited AF 1
• Never use diltiazem or verapamil in heart failure with reduced ejection fraction 5
• Never use digoxin as monotherapy in paroxysmal AF 1
• Avoid underdosing DOACs; use reduced doses only when specific criteria are met 3
• Do not perform cardioversion without appropriate anticoagulation if AF duration >24 hours 2
• Correct hypokalemia before initiating antiarrhythmic therapy 1

Ongoing Management

• Monitor renal function at least annually with DOACs, more frequently if clinically indicated 1
• For warfarin: monitor INR weekly during initiation, then monthly when stable 1, 4
• Reassess therapy periodically and evaluate for new modifiable risk factors 1
• Manage comorbidities: hypertension, heart failure, diabetes, obesity, obstructive sleep apnea 1, 3