Atrial fibrillation at a glance.
AFib on one page: CHA₂DS₂-VASc, HAS-BLED, DOAC dosing, rate vs rhythm, cardioversion windows, and the special situations that actually come up on call.
Reviewed October 2026 · verify against current guidelines
Atrial fibrillation at a glance.
Definition and epidemiology
Supraventricular tachyarrhythmia with uncoordinated atrial activity → ineffective atrial contraction. ECG: irregularly irregular R-R, absent P waves, fibrillatory baseline. Most common sustained arrhythmia. Lifetime risk ~1 in 3 (age ≥55). Prevalence rises sharply >65 yr.
Classification
| Paroxysmal | Terminates ≤7 d (usually <48 h). |
|---|---|
| Persistent | >7 d, requires cardioversion. |
| Long-standing persistent | >12 mo continuous. |
| Permanent | Rhythm-control abandoned. |
| Valvular | Moderate–severe MS or mechanical valve. |
Diagnosis / workup
- 12-lead ECG (confirm); Holter / event monitor / implantable loop if paroxysmal.
- TTE — LA size, LV function, valvular disease.
- Labs: TSH, CBC, BMP, LFTs, coags, HbA1c.
- Screen for OSA, alcohol, stimulants, thyrotoxicosis.
Risk factors and triggers
| Cardiac | HTN, HF, CAD, valvular disease, cardiomyopathy, prior cardiac surgery, congenital HD. |
|---|---|
| Non-cardiac | Age, obesity, OSA, diabetes, hyperthyroidism, CKD, alcohol ("holiday heart"), stimulants, sepsis, PE, post-op. |
Presentation
Palpitations, fatigue, dyspnea, reduced exercise tolerance, chest discomfort, lightheadedness, syncope. Up to ~1/3 asymptomatic. Red flags: hemodynamic instability, ischemia, decompensated HF → urgent cardioversion.
Stroke risk — CHA₂DS₂-VASc
| Criterion | Points | |
|---|---|---|
| C | CHF / LV dysfunction | 1 |
| H | Hypertension | 1 |
| A₂ | Age ≥75 | 2 |
| D | Diabetes mellitus | 1 |
| S₂ | Prior stroke / TIA / thromboembolism | 2 |
| V | Vascular disease (MI, PAD, aortic plaque) | 1 |
| A | Age 65–74 | 1 |
| Sc | Sex category (female) | 1 |
Anticoagulate
- Men ≥2, Women ≥3 → OAC recommended.
- Men 1, Women 2 → OAC reasonable (shared decision).
- Men 0, Women 1 → no antithrombotic.
Bleeding risk — HAS-BLED
| H | Hypertension (uncontrolled, SBP >160) |
|---|---|
| A | Abnormal renal / liver function (1 each) |
| S | Stroke history |
| B | Bleeding history or predisposition |
| L | Labile INR (warfarin) |
| E | Elderly (>65) |
| D | Drugs/alcohol (1 each: NSAIDs, antiplt, EtOH ≥8/wk) |
≥3 = high risk → modify reversible factors; not a reason to withhold OAC.
Anticoagulation — agent selection
| Agent | Dose (standard) | Renal cautions / notes |
|---|---|---|
| Apixaban | 5 mg BID (2.5 mg BID if ≥2: age ≥80, wt ≤60 kg, Cr ≥1.5) | CrCl >15; preferred in CKD / elderly / high bleed risk |
| Rivaroxaban | 20 mg daily w/ evening meal (15 mg if CrCl 15–50) | Avoid CrCl <15 |
| Dabigatran | 150 mg BID (75 mg BID if CrCl 15–30) | Avoid CrCl <15; dyspepsia common; idarucizumab reversal |
| Edoxaban | 60 mg daily (30 mg if CrCl 15–50, wt ≤60, P-gp inh) | Avoid CrCl >95 (less effective) or <15 |
| Warfarin | INR 2–3 (2.5–3.5 mech mitral valve) | Required for mod–severe MS or mechanical valve; TTR >70% |
Rate control
Target HR <110 bpm (lenient) if asymptomatic + preserved LV; stricter <80 if symptomatic. 1st line: β-blocker (metoprolol, carvedilol, bisoprolol) or non-DHP CCB (diltiazem, verapamil — avoid in HFrEF). Add/alt: digoxin (esp. HFrEF, sedentary), amiodarone (refractory, hemodynamic compromise).
Rhythm control
Consider for: symptomatic despite rate control, younger pts, first episode, HF, tachycardia-mediated cardiomyopathy. EAST-AFNET 4 / EARLY-AF: early rhythm control improves outcomes if <1 yr. Antiarrhythmics: flecainide/propafenone (no structural HD), sotalol, dofetilide, amiodarone (HF/structural HD; toxicity profile). Catheter ablation (PVI): 1st-line option esp. paroxysmal; preferred over drugs in HFrEF (CASTLE-AF, CABANA).
Cardioversion
| Unstable | Immediate synchronized DCCV. |
|---|---|
| Stable, <48 h onset | May cardiovert; anticoag at presentation, ≥4 wk after. |
| ≥48 h or unknown | 3 wk therapeutic OAC or TEE to exclude LAA thrombus, then 4 wk OAC post-CV (longer if CHA₂DS₂-VASc qualifies). |
Special situations
| LAA occlusion (Watchman) | Consider if OAC contraindicated. |
|---|---|
| Post-op AF (cardiac surgery) | Usually transient; OAC if persists or CHA₂DS₂-VASc qualifies. |
| AF + ACS/PCI | Triple therapy ≤1 wk → OAC + P2Y12 (clopidogrel) to 12 mo → OAC alone. |
| Pregnancy | Avoid DOACs/warfarin (1st trim); LMWH preferred. |
For clinician reference. Not a substitute for guidelines or judgment. Use clinical judgment; verify dosing per local formulary.
Sources
Verify against current guidelines and local protocol before acting.
- 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation.
- 2024 ESC Guidelines for the Management of Atrial Fibrillation.
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