If you have palpitations or an irregular heartbeat, get an ECG; if atrial fibrillation is found, ask a doctor to assess anticoagulants for stroke prevention, and do not substitute aspirin

An ECG costs a few dozen yuan. Warfarin is inexpensive, but requires regular blood tests to adjust the dose. Newer anticoagulants require less frequent blood testing but cost more. The hard part is taking medicine every day even without symptoms, and telling the doctor that you take anticoagulants before a tooth extraction or surgery.

In atrial fibrillation, the atria quiver irregularly, allowing blood to pool and clots to form. A clot that travels into a blood vessel in the brain causes a stroke. The most common symptoms are palpitations, tiring easily with activity, and chest discomfort; about 25% of people report no symptoms. A single-lead ECG lasting at least 30 seconds, or a standard 12-lead ECG lasting at least 10 seconds, can establish the diagnosis. A 2007 meta-analysis pooled 29 randomized trials involving 28044 people. Compared with no medication, dose-adjusted warfarin reduced strokes by about 60%: a 64% reduction, with a confidence interval of 49%–74%. Antiplatelet drugs such as aspirin reduced them by only about 20%: a 22% reduction, with a confidence interval of 6%–35%. In direct comparisons, warfarin reduced strokes by a further 39% compared with antiplatelet drugs. The absolute annual increase in major bleeding outside the brain was no more than 0.3 percentage points. A Cochrane review examined 2313 people with no previous stroke. The warfarin group had an odds ratio for death of 0.69 (OR 0.69; 95% CI 0.50–0.94). Death was rare, so the odds ratio was close to relative risk: deaths were about 30% lower. Four large trials involving 71683 people compared newer oral anticoagulants with warfarin. The newer drugs reduced stroke and embolism by another 19% (RR 0.81) and deaths by 10% (RR 0.90). Intracranial bleeding fell by 52% (RR 0.48), but gastrointestinal bleeding rose by 25% (RR 1.25). Aspirin cannot replace anticoagulants. Among 5599 people unsuitable for warfarin, apixaban reduced stroke and embolism by 55% compared with aspirin (HR 0.45). Major bleeding occurred at annual rates of 1.4% versus 1.2%, without a detectable difference (HR 1.13, confidence interval 0.74–1.75). Another trial enrolled only people aged 75 and older, 973 in total. Warfarin reduced the combined outcome of fatal or disabling stroke, intracranial bleeding, and arterial embolism by 52% compared with aspirin (RR 0.48). Bleeding outside the brain occurred at annual rates of 1.4% versus 1.6%. China's 2023 atrial fibrillation guideline uses the CHA2DS2-VASc-60 score. Heart failure, hypertension, diabetes, vascular disease, age 60–64, and female sex each score 1 point; age 65 and older and previous stroke each score 2 points. Oral anticoagulants are recommended for men scoring at least 2 and women scoring at least 3. For men scoring 1 and women scoring 2, they may be considered after weighing bleeding risk and personal preferences. The guideline does not recommend antiplatelet drugs to prevent strokes caused by atrial fibrillation. The 2023 US guideline says the decision depends on stroke risk, rather than whether atrial fibrillation occurs intermittently or continuously. It also says bleeding risk scores should not be used alone to decide against anticoagulation; they should identify bleeding risk factors that can be changed. A 2014–2016 Chinese survey of people aged 45 and older found atrial fibrillation in 1.8%, representing about 7.9 million people. Awareness of the condition was 78.3% in urban areas but only 35.3% in rural areas. Only 6.0% of those with high-risk atrial fibrillation were using anticoagulants. In a 2020–2021 national survey, 43.8% of the atrial fibrillation cases detected were newly discovered. Among previously diagnosed people, 32.1% were using anticoagulants, compared with only 19.8% in rural areas.

Hart RG, Pearce LA, Aguilar MI. (2007). Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation. Annals of Internal Medicine, 146(12), 857-867. https://doi.org/10.7326/0003-4819-146-12-200706190-00007；Aguilar MI, Hart R. (2005). Oral anticoagulants for preventing stroke in patients with non-valvular atrial fibrillation and no previous history of stroke or transient ischemic attacks. Cochrane Database of Systematic Reviews, (3), CD001927. https://doi.org/10.1002/14651858.CD001927.pub2；Ruff CT, Giugliano RP, Braunwald E, et al. (2014). Comparison of the efficacy and safety of new oral anticoagulants with warfarin in patients with atrial fibrillation: a meta-analysis of randomised trials. Lancet, 383(9921), 955-962. https://doi.org/10.1016/S0140-6736(13)62343-0；Connolly SJ, Eikelboom J, Joyner C, et al. (2011). Apixaban in patients with atrial fibrillation. New England Journal of Medicine, 364(9), 806-817. https://doi.org/10.1056/NEJMoa1007432；Mant J, Hobbs FD, Fletcher K, et al. (2007). Warfarin versus aspirin for stroke prevention in an elderly community population with atrial fibrillation (the Birmingham Atrial Fibrillation Treatment of the Aged Study, BAFTA): a randomised controlled trial. Lancet, 370(9586), 493-503. https://doi.org/10.1016/S0140-6736(07)61233-1；Ma CS, Wu SL, Liu SW, Han YL, Chinese Society of Cardiology, et al. (2024). Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. Journal of Geriatric Cardiology, 21(3), 251-314（中华医学会心血管病学分会等 2023 年《心房颤动诊断和治疗中国指南》的英文版）. https://doi.org/10.26599/1671-5411.2024.03.009；Joglar JA, Chung MK, Armbruster AL, et al. (2024). 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. Circulation, 149(1), e1-e156. https://doi.org/10.1161/CIR.0000000000001193；Du X, Guo L, Xia S, et al. (2021). Atrial fibrillation prevalence, awareness and management in a nationwide survey of adults in China. Heart. https://doi.org/10.1136/heartjnl-2020-317915；Shi S, Tang Y, Zhao Q, et al. (2022). Prevalence and risk of atrial fibrillation in China: A national cross-sectional epidemiological study. Lancet Regional Health – Western Pacific, 23, 100439. https://doi.org/10.1016/j.lanwpc.2022.100439；US Preventive Services Task Force (2022). Screening for Atrial Fibrillation: US Preventive Services Task Force Recommendation Statement. JAMA, 327(4), 360-367. https://doi.org/10.1001/jama.2021.23732；Svennberg E, Friberg L, Frykman V, et al. (2021). Clinical outcomes in systematic screening for atrial fibrillation (STROKESTOP): a multicentre, parallel group, unmasked, randomised controlled trial. Lancet, 398(10310), 1498-1506. https://doi.org/10.1016/S0140-6736(21)01637-8；Svendsen JH, Diederichsen SZ, Højberg S, et al. (2021). Implantable loop recorder detection of atrial fibrillation to prevent stroke (The LOOP Study): a randomised controlled trial. Lancet, 398(10310), 1507-1516. https://doi.org/10.1016/S0140-6736(21)01698-6

The controversy concerns screening, rather than anticoagulation after atrial fibrillation is diagnosed. Evidence is insufficient to determine whether people without symptoms should undergo dedicated screening. In 2022, the US Preventive Services Task Force concluded that the evidence was insufficient to assess the balance of benefits and harms. A Swedish study invited people aged 75–76 to undergo ECG recording over two weeks. After about 7 years, the combined outcome of death, stroke, and bleeding was only 4% lower, just reaching statistical significance. A Danish study implanted long-term ECG recorders in people aged 70–90. Atrial fibrillation was detected in 31.8% versus 12.2%, but the reduction in strokes was not statistically significant. China's 2023 guideline says pulse checks or ECGs may be considered opportunistically during medical visits for people aged 65 and older. People with symptoms should therefore get checked; those aged 65 and older can ask the doctor to check their pulse during a visit, without buying a device specifically for screening. Once taking anticoagulants, do not add painkillers such as ibuprofen on your own; see Section 34, Item 3 (ask a doctor before taking ibuprofen if you take anticoagulants). Treatment is long term: do not stop because you feel fine; see Section 16, Item 1 (take medicine for the full prescribed course). High blood pressure also contributes to the score; see Item 7 in this section (measure blood pressure). People with atrial fibrillation do not all need to give up coffee; see Section 2, Item 26 (drink three to four cups of coffee a day). For sudden facial drooping or weakness on one side, call China's ambulance number, 120, immediately, whether or not you take medication; see Section 13, Item 3 (sudden facial drooping or weakness in one arm). The main beneficiaries are you and older family members.