Management of Atrial Fibrillation
For patients with atrial fibrillation, oral anticoagulation with a direct oral anticoagulant (DOAC) such as apixaban, dabigatran, rivaroxaban, or edoxaban is the cornerstone of treatment for stroke prevention in those with ≥1 non-sex CHA₂DS₂-VASc risk factor, combined with rate control using beta-blockers or non-dihydropyridine calcium channel blockers, while addressing underlying conditions like hypertension and heart failure. 1, 2
Stroke and Systemic Embolism Prevention
Risk Stratification
Use the CHA₂DS₂-VASc score to determine stroke risk, which includes: congestive heart failure (1 point), hypertension (1 point), age ≥75 years (2 points), diabetes (1 point), prior stroke/TIA/thromboembolism (2 points), vascular disease (1 point), age 65-74 years (1 point), and female sex (1 point). 1, 2
Low-risk patients (CHA₂DS₂-VASc = 0 in males, 1 in females where the point is from sex alone) require no antithrombotic therapy. 1, 2
All patients with ≥1 non-sex CHA₂DS₂-VASc risk factor require oral anticoagulation, not aspirin or antiplatelet therapy. 1, 2
Choice of Anticoagulant
DOACs are preferred over warfarin for nonvalvular atrial fibrillation due to lower intracranial hemorrhage risk with similar or superior efficacy. 1, 2, 3
DOAC Options:
Apixaban 5 mg twice daily (or 2.5 mg twice daily if patient has ≥2 of: age ≥80 years, weight ≤60 kg, serum creatinine ≥1.5 mg/dL). 1, 3
Dabigatran 150 mg twice daily is suggested over warfarin. 1, 2
Warfarin Indications (INR 2.0-3.0):
Mechanical heart valves (INR ≥2.5 based on valve type). 1, 2
End-stage renal disease or dialysis patients (dabigatran contraindicated in severe renal impairment). 2
Monitor INR weekly during initiation, then monthly when stable. 1
Bleeding Risk Assessment
Assess bleeding risk using the HAS-BLED score at every patient contact: hypertension (uncontrolled), abnormal renal/liver function, stroke history, bleeding predisposition, labile INR, elderly (>65), drugs (NSAIDs/aspirin)/alcohol. 1, 2
A HAS-BLED score ≥3 indicates high bleeding risk requiring caution and frequent monitoring, but should not be used to exclude patients from anticoagulation—instead, focus on correcting modifiable risk factors (uncontrolled blood pressure, alcohol excess, concomitant NSAIDs/aspirin). 1, 2
Blood pressure must be controlled to <140/90 mmHg when anticoagulation is initiated to minimize bleeding risk. 5
Critical Pitfalls to Avoid
Never use aspirin or antiplatelet therapy alone for stroke prevention in AF—aspirin reduces stroke risk by only 22% compared to 62% with oral anticoagulation, with similar bleeding risk especially in the elderly. 1, 2, 6
Never combine antiplatelet therapy with anticoagulation unless there is a specific indication (e.g., recent acute coronary syndrome)—this significantly increases bleeding without additional stroke prevention benefit. 2
Do not discontinue anticoagulation after cardioversion or ablation if stroke risk factors persist. 2, 3
Rate Control Strategy
First-Line Agents
Beta-blockers are the preferred first-line agents for rate control, particularly when hypertension or heart failure coexists. 1, 5
Metoprolol 25-50 mg daily or carvedilol, titrated based on heart rate and blood pressure response. 5
Non-dihydropyridine calcium channel blockers (diltiazem or verapamil) are alternatives if beta-blockers are contraindicated, but avoid in decompensated heart failure as they may worsen hemodynamics. 1, 5
Rate Control Targets
Target resting heart rate <110 bpm is acceptable for most patients with persistent AF and stable ventricular function (LVEF ≥40%)—strict rate control (<80 bpm at rest) provides no additional benefit. 1
Monitor heart rate at rest and during activity (e.g., 6-minute walk test) to assess adequacy of rate control. 5
When Pharmacologic Rate Control Fails
Digoxin can be added to beta-blockers or calcium channel blockers but should never be used as sole agent for rate control, especially in paroxysmal AF. 1, 5
Catheter ablation of the AV node with permanent pacemaker implantation may be considered when rate cannot be controlled pharmacologically or tachycardia-mediated cardiomyopathy is suspected, but only after trial of medication. 1
Consider biventricular pacing (with or without defibrillator) for patients with impaired LV function (LVEF <35%) undergoing AV nodal ablation. 1
Management of Underlying Conditions
Hypertension Management
Combine beta-blocker with angiotensin receptor blocker (ARB) or ACE inhibitor for optimal blood pressure control in AF patients with hypertension. 5
Valsartan combined with metoprolol or carvedilol is particularly effective in elderly patients with AF and hypertension. 5
Monitor renal function and electrolytes (especially potassium) closely in patients on ARBs and diuretics. 5
Heart Failure Management
Beta-blockers remain first-line for rate control in heart failure patients with AF. 1, 5
Avoid non-dihydropyridine calcium channel antagonists in decompensated heart failure—intravenous administration may exacerbate hemodynamic compromise. 1
Anticoagulation with warfarin or DOAC is recommended for heart failure patients with AF (LVEF ≤35% or NYHA Class ≥2 is a CHA₂DS₂-VASc risk factor). 1
Special Clinical Scenarios
Pre-excitation Syndromes (WPW)
- Never give intravenous digoxin or non-dihydropyridine calcium channel antagonists to patients with AF and pre-excitation—these may paradoxically accelerate ventricular response. 1
Peri-cardioversion Management
For AF ≥48 hours or unknown duration, anticoagulate for ≥3 weeks before and ≥4 weeks after cardioversion (electrical or pharmacological) with warfarin (INR 2.0-3.0) or DOAC. 1
Continue lifelong anticoagulation after cardioversion in patients with stroke risk factors, regardless of apparent sinus rhythm maintenance. 1
Temporary Interruption for Surgery
Discontinue DOACs at least 48 hours before procedures with moderate-to-high bleeding risk, or 24 hours before low-bleeding-risk procedures. 3
Bridging anticoagulation is not generally required during the 24-48 hour interruption period. 3
Restart anticoagulation as soon as adequate hemostasis is established. 3