Atrial Fibrillation: High-Yield Management Notes

Core Management Objectives

The management of atrial fibrillation centers on five simultaneous goals: prevention of thromboembolism, symptom relief, optimal management of cardiovascular comorbidities, rate control, and correction of rhythm disturbance. 1

These goals are not mutually exclusive and should be pursued simultaneously 1
Initial strategy may differ from long-term therapeutic goals 1
Early cardioversion is necessary if AF causes hypotension or worsening heart failure 1

Initial Assessment

Diagnostic Workup

Confirm diagnosis with 12-lead ECG to document the arrhythmia and assess ventricular rate 1, 2
Obtain transthoracic echocardiogram to identify valvular disease, left atrial size, left ventricular function, and structural abnormalities 1, 2
Complete blood tests for thyroid function (TSH), renal function (creatinine, eGFR), hepatic function (AST, ALT), and electrolytes (potassium, magnesium) 2
Chest X-ray to assess for pulmonary edema or underlying lung disease 2

Risk Stratification

Calculate CHA₂DS₂-VASc score immediately to guide anticoagulation decisions 2
- Congestive heart failure (1 point)
- Hypertension (1 point)
- Age ≥75 years (2 points)
- Diabetes mellitus (1 point)
- Stroke/TIA/thromboembolism history (2 points)
- Vascular disease (1 point)
- Age 65-74 years (1 point)
- Sex category female (1 point)

Anticoagulation Strategy

Indications and Drug Selection

Direct oral anticoagulants (DOACs) are preferred over warfarin in eligible patients due to lower risk of intracranial hemorrhage. 2, 3

Initiate oral anticoagulation for all patients with CHA₂DS₂-VASc score ≥2 2
For patients age ≥75 years, oral anticoagulation is mandatory (Class I recommendation) 2
For heart failure or LVEF ≤35%, anticoagulation with INR 2.0-3.0 is mandatory 2

DOAC Dosing

Apixaban 5 mg twice daily (or 2.5 mg twice daily if patient meets ≥2 of these criteria: age ≥80 years, weight ≤60 kg, or creatinine ≥1.5 mg/dL) 2
Dabigatran, edoxaban, or rivaroxaban are acceptable alternatives at standard doses unless specific dose-reduction criteria are met 2
Avoid combining anticoagulants with antiplatelet agents unless specifically indicated for acute vascular event 2

Warfarin Management (When DOACs Contraindicated)

Target INR 2.0-3.0 for non-valvular atrial fibrillation 4
Monitor INR weekly during initiation, then monthly when stable 1, 2
For mechanical heart valves, warfarin is mandatory (DOACs are contraindicated) 4, 5, 4
For mitral stenosis, use warfarin (not DOACs) 4

Special Anticoagulation Considerations

Continue anticoagulation regardless of rhythm status if stroke risk factors persist 2, 3
Assess and manage modifiable bleeding risk factors, but do not use bleeding risk scores to withhold anticoagulation 2
Evaluate renal function at least annually when using DOACs, more frequently if clinically indicated 2
Avoid DOACs in patients with triple-positive antiphospholipid syndrome (use warfarin instead) 5

Rate Control Strategy

First-Line Agents by Clinical Scenario

Rate control with chronic anticoagulation is the recommended strategy for the majority of patients with atrial fibrillation. 1

Preserved Ejection Fraction (LVEF >40%)

Beta-blockers (atenolol, metoprolol) OR non-dihydropyridine calcium channel blockers (diltiazem, verapamil) are first-line 1, 2, 3
Diltiazem 60-120 mg PO three times daily (or 120-360 mg extended release) 2
Verapamil 40-120 mg PO three times daily (or 120-480 mg extended release) 2
Digoxin is only effective for rate control at rest and should be second-line or used in combination 1

Reduced Ejection Fraction (LVEF ≤40%)

Beta-blockers and/or digoxin are recommended due to favorable effects on morbidity and mortality in systolic heart failure 1, 2, 3
Digoxin 0.0625-0.25 mg per day 2
Avoid non-dihydropyridine calcium channel blockers (diltiazem, verapamil) due to negative inotropic effects 1

Special Populations

For COPD or active bronchospasm: use diltiazem or verapamil (avoid beta-blockers, sotalol, propafenone) 2, 3
For high catecholamine states (acute illness, post-operative, thyrotoxicosis): use beta-blockers 2
For elderly patients with minor symptoms (EHRA score 1): rate control should be initial approach 1

Rate Control Targets

Lenient rate control (resting heart rate <110 bpm) is reasonable as long as patients remain asymptomatic and LVEF is preserved 2
Strict rate control (resting heart rate <80 bpm) may be considered for symptomatic patients 2

Combination Therapy

Digoxin plus beta-blocker or calcium channel blocker provides better control at rest and during exercise 1, 2
Avoid digoxin as sole agent in paroxysmal AF (Class III recommendation) 2

Rhythm Control Strategy

When to Consider Rhythm Control

Rhythm control is appropriate when based on patient symptoms, exercise tolerance, and patient preference, but has not been shown superior to rate control in reducing morbidity and mortality. 1

Consider rhythm control for symptomatic patients despite adequate rate control 1, 2, 3
Consider rhythm control for new-onset AF or younger, more active patients 1, 2
Pursue rhythm control if AF causes rate-related cardiomyopathy (newly detected heart failure with rapid ventricular response) 1

Cardioversion Approach

Immediate Cardioversion

Perform immediate electrical cardioversion for acute AF with hemodynamic instability 1, 2, 3
Correct hypokalemia before initiating antiarrhythmic therapy 2

Planned Cardioversion Anticoagulation Protocol

For AF duration <48 hours: may proceed with cardioversion after initiating anticoagulation 2
For AF duration >48 hours or unknown duration: require at least 3 weeks of therapeutic anticoagulation before cardioversion 1, 2
Continue anticoagulation for minimum 4 weeks after cardioversion, and long-term if stroke risk factors present 1, 2
Alternative approach: transesophageal echocardiography with short-term anticoagulation followed by early cardioversion if no intracardiac thrombus 1

Antiarrhythmic Drug Selection Algorithm

Most patients converted to sinus rhythm should not be placed on rhythm maintenance therapy since risks outweigh benefits, except in selected patients whose quality of life is compromised. 1

No Structural Heart Disease

First-choice agents: dronedarone, flecainide, propafenone, or sotalol 2, 6
For pharmacological cardioversion: flecainide or propafenone 2, 3

Coronary Artery Disease (Without Heart Failure)

Sotalol is preferred first-line due to beta-blockade plus antiarrhythmic effect 2

Hypertension Without Left Ventricular Hypertrophy

Flecainide or propafenone may be used 2

Abnormal LV Function but LVEF >35%

Dronedarone, sotalol, or amiodarone 2, 6

Heart Failure or LVEF ≤35%

Amiodarone is the only drug usually recommended 2, 6
Amiodarone 300 mg IV diluted in 250 ml of 5% glucose over 30-60 minutes for emergency situations 2

Catheter Ablation

Consider catheter ablation when antiarrhythmic drugs fail to control symptoms 1, 2, 3
May be considered as first-line option in patients with paroxysmal AF 2
In heart failure patients, AF ablation may improve LV function and quality of life but is less effective than in patients with intact cardiac function 1
AV node ablation with pacemaker insertion should be used as last resort when rate control cannot be achieved 1

Special Clinical Scenarios

Wolff-Parkinson-White Syndrome with Pre-excited AF

If hemodynamically unstable: immediate DC cardioversion 2
If stable: IV procainamide or ibutilide 2
NEVER use AV nodal blockers (adenosine, digoxin, diltiazem, verapamil, amiodarone) as they can accelerate ventricular rate and precipitate ventricular fibrillation 2
Catheter ablation of accessory pathway is definitive treatment 2

Postoperative AF

Beta-blocker or non-dihydropyridine calcium channel blocker for rate control 2
Preoperative amiodarone reduces incidence in high-risk cardiac surgery patients 2

AF with Mechanical Prosthetic Valves

Warfarin is mandatory (DOACs are absolutely contraindicated) 4, 5, 4
For bileaflet valve in aortic position: target INR 2.5 (range 2.0-3.0) 4
For tilting disk or bileaflet valves in mitral position: target INR 3.0 (range 2.5-3.5) 4
For caged ball or caged disk valves: target INR 3.0 (range 2.5-3.5) plus aspirin 75-100 mg/day 4

AF with Bioprosthetic Valves

Warfarin with target INR 2.5 (range 2.0-3.0) for valves in mitral position and suggested for aortic position for first 3 months after valve insertion 4

First-Documented AF with Adequate Rate Control

Does not require hospitalization if hemodynamically stable 2

Common Pitfalls to Avoid

Underdosing anticoagulation or inappropriate discontinuation increases stroke risk 2, 3
Most strokes in trials occurred after warfarin stopped or when INR was subtherapeutic 2, 7
Using digoxin as sole agent for rate control in paroxysmal AF is ineffective 2
Failing to continue anticoagulation after cardioversion in patients with stroke risk factors 2, 3
Attempting cardioversion without appropriate anticoagulation in patients with AF lasting >48 hours 2, 3
Mislabeling AF with rapid rate and wide QRS as ventricular tachycardia (consider AF with aberrancy or pre-excitation) 2
Using non-dihydropyridine calcium channel blockers in decompensated heart failure 1
Performing catheter ablation without prior trial of medical therapy (except in selected cases) 2

Key Evidence: Rate vs. Rhythm Control

The AFFIRM trial demonstrated no survival advantage with rhythm control versus rate control, with more hospitalizations and adverse drug effects in the rhythm control group. 1, 2, 7

Rate control with chronic anticoagulation offers potential advantages including lower risk of adverse drug effects 1, 7
Rhythm control may be inferior in some patient subgroups 1
Both strategies require continuation of anticoagulation based on stroke risk 1, 2, 7

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