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Atrial fibrillation
Atrial fibrillation involves three separate decisions: whether to anticoagulate (by the stroke-risk score), how to control rate or rhythm, and what to do when the patient is unstable — immediate electrical cardioversion.
Why it matters in the exam
This is the most common arrhythmia and the most examined. Questions test the CHA2DS2-VASc calculation and the anticoagulation decision, the choice between a DOAC and warfarin (warfarin only with a mechanical valve or moderate-to-severe mitral stenosis), DOAC dose adjustment for kidney function, age and weight, and reversal agents: idarucizumab for dabigatran and andexanet alfa for the factor Xa inhibitors. Candidates are also asked the 24-hour rule before cardioversion and how to choose a rate-control drug by LV function.
Other common cases: atrial fibrillation with WPW (irregular rhythm with wide, changing QRS complexes), in which AV-node blockers are forbidden; atrial fibrillation on ibrutinib or after surgery; and an elderly patient who falls, in whom the stroke risk is higher than the bleeding risk from falls. A high HAS-BLED score leads to correcting bleeding risk factors, not to withholding anticoagulation.
Key points
- Anticoagulate by CHA2DS2-VASc: a score of 2 in men, or of 3 in women, is enough.
- A DOAC is preferred, except with a mechanical valve and moderate-to-severe mitral stenosis (warfarin).
- Unstable: immediate electrical cardioversion; stable: rate control and consider rhythm control.
- Beyond 24 hours: 3 weeks of anticoagulation or TEE before cardioversion, and 4 weeks after.
- AF with WPW: no AV-node blockers; cardioversion or procainamide.
Summary table
| Decision | The rule | Details | Trap |
|---|---|---|---|
| Anticoagulation | CHA2DS2-VASc of 2 or more in men or 3 or more in women — recommended; 1 in men — consider | ESC 2024 uses CHA2DS2-VA without sex: 2 or more recommended | Aspirin is not a substitute for anticoagulation |
| Which anticoagulant | DOAC preferred over warfarin | Warfarin with a mechanical valve or moderate-to-severe mitral stenosis | Apixaban 2.5 mg twice daily if 2 of: age 80, weight 60 kg or less, creatinine 1.5 or more |
| Rate control | Beta-blocker, diltiazem or verapamil, digoxin | In HFrEF: beta-blocker or digoxin, not diltiazem/verapamil | Initial target resting heart rate below 110 |
| Rhythm control | Electrical or drug cardioversion, ablation | Flecainide or propafenone only without structural heart disease; amiodarone with structural disease | Ablation is a first-line option in symptomatic paroxysmal AF |
| Cardioversion | AF longer than 24 hours (ESC 2024; ACC/AHA and older textbooks: 48 hours) or of unknown duration | 3 weeks of anticoagulation or TEE before, and 4 weeks after | Unstable patient — immediate electrical cardioversion |
| Reversal | Life-threatening bleeding | Dabigatran: idarucizumab; apixaban/rivaroxaban: andexanet alfa or PCC | Warfarin: vitamin K and PCC |
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Sources
- ESC Guidelines for the management of atrial fibrillation, 2024 — Stroke prevention, rate and rhythm control (AF-CARE)
- ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation, 2023 — Anticoagulation and rhythm control
- Harrison's Principles of Internal Medicine, 21st edition (2022) — Atrial Fibrillation
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.