Atrial Fibrillation — Rate, Rhythm, and Anticoagulation
The Three Decisions Every APP Must Make
Atrial Fibrillation — Rate, Rhythm, and Anticoagulation
Every patient with AF requires three decisions — in this order: anticoagulate or not, control the rate, then decide about rhythm. The order matters. Stroke prevention comes first.
Part 1 — Rate Control vs. Rhythm Control
Rate control is first-line for most patients. Rhythm control is added when symptoms persist despite rate control, or when early rhythm control is preferred (recent-onset AF, tachycardia-induced cardiomyopathy, younger patients with few comorbidities).
| Rate Control | Rhythm Control | |
|---|---|---|
| Goal | Resting HR <100–110 bpm (lenient); <80 bpm if symptomatic or tachycardia-mediated cardiomyopathy | Restore and maintain sinus rhythm |
| Preferred for | Asymptomatic or mildly symptomatic AF; permanent AF; older patients with multiple comorbidities | Persistent symptoms on rate control; new HFrEF + AF; younger patients; recent-onset AF |
| First-line drugs | Beta blockers (metoprolol, carvedilol); nondihydropyridine CCBs (diltiazem, verapamil) if LVEF ≥40% | Cardioversion; antiarrhythmic drugs (see Part 2) |
| Adjunct | Digoxin (target level <1.2 ng/mL) — add-on only | Catheter ablation (PVI) for refractory or preferred first-line in selected patients |
Part 2 — Cardioversion and Antiarrhythmic Drugs
| Cardioversion Scenario | Required Steps |
|---|---|
| AF <48 hours | Anticoagulate at time of cardioversion + ≥4 weeks after. Can cardiovert without pre-procedure anticoagulation if hemodynamically stable. |
| AF ≥48 hours or unknown duration | Option A: 3 weeks therapeutic anticoagulation before cardioversion, then ≥4 weeks after. Option B: TEE to exclude LAA thrombus, then cardiovert, then ≥4 weeks anticoagulation. |
| Hemodynamically unstable | Immediate synchronized cardioversion regardless of anticoagulation status (Class I). |
Antiarrhythmic Drug Selection (guided by LV function and comorbidities):
| Patient Profile | Preferred Drugs | Avoid |
|---|---|---|
| Normal LV, no prior MI, no structural disease | Flecainide, propafenone, dronedarone, dofetilide | — |
| Prior MI or structural heart disease (HFrEF ≤40%) | Amiodarone, dofetilide | Flecainide, propafenone (Class III Harm) |
| NYHA III–IV HF or decompensated HF within 4 weeks | Amiodarone, dofetilide | Dronedarone (Class III Harm) |
Part 3 — CHA2DS2-VASc: When to Anticoagulate
| Risk Factor | Points |
|---|---|
| C — Congestive heart failure or LVEF ≤40% | 1 |
| H — Hypertension | 1 |
| A2 — Age ≥75 years | 2 |
| D — Diabetes mellitus | 1 |
| S2 — Stroke, TIA, or systemic thromboembolism (history) | 2 |
| V — Vascular disease (prior MI, PAD, or aortic plaque) | 1 |
| A — Age 65–74 years | 1 |
| Sc — Sex category female | 1 |
| Score | Decision | Guideline |
|---|---|---|
| 0 (male) / 1 (female) | Anticoagulation not recommended | Class III Harm (LOE B-R) |
| 1 (male) / 2 (female) | Reasonable — shared decision-making | Class IIa (LOE A) |
| ≥2 (male) / ≥3 (female) | Anticoagulate | Class I (LOE A) |
DOAC Selection and Key Considerations:
| Drug | Standard Dose | Key Point |
|---|---|---|
| Apixaban | 5 mg BID | Reduce to 2.5 mg BID if ≥2 of: age ≥80, weight ≤60 kg, SCr ≥1.5 mg/dL. Lowest GI bleed risk vs. warfarin. |
| Rivaroxaban | 20 mg QD with evening meal | Must take with food — absorption drops 30–40% without it. Reduce to 15 mg QD if CrCl 15–50 mL/min. |
| Dabigatran | 150 mg BID | Reduce to 75 mg BID if CrCl 15–30 mL/min. Highest GI bleed rate. Reversal: idarucizumab. |
| Edoxaban | 60 mg QD | Contraindicated if CrCl >95 mL/min (paradoxically reduced efficacy at high CrCl). Reduce to 30 mg QD if CrCl 15–50 mL/min. |
| Warfarin | Adjust to INR 2.0–3.0 | Required for mechanical heart valves and moderate-to-severe mitral stenosis. DOACs are Class III Harm in these two conditions. |
In most patients with AF: anticoagulate first, rate control second, rhythm control third. CHA2DS2-VASc ≥2 (men) or ≥3 (women) → anticoagulate. DOACs are preferred over warfarin unless the patient has a mechanical heart valve or severe mitral stenosis — those two indications require warfarin. Bleeding risk scores identify what to fix, not who to exclude from anticoagulation.
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