Background It is uncertain whether stroke risk of asymptomatic ambulatory atrial fibrillation (AA-AF) incidentally detected in primary care is comparable with other clinical AF presentations in primary care or hospital. Methods The stoke risk of 22,035 patients with incident nonvalvular AF from the United Kingdom primary care Clinical Practice Research Datalink with linkage to hospitalization and mortality data was compared with 23,605 controls without AF (age- and sex-matched 5:1 to 5,409 AA-AF patients). Incident AF included 5,913 with symptomatic ambulatory AF (SA-AF); 4,989 with primary and 5,724 with nonprimary hospital AF discharge diagnosis (PH-AF and non-PH-AF); and 5,409 with AA-AF. Ischemic stroke adjusted subhazard ratios (aSHRs) within 3 years of AA-AF were compared with SA-AF, PH-AF, non-PH-AF, and no AF, accounting for mortality as competing risk and adjusted for ischemic stroke risk factors. Results There were 1,026 ischemic strokes in 49,544 person-years in patients with incident AF (crude incidence rate: 2.1 ischemic strokes/100 person-years). Ischemic stroke aSHR over 3 years showed no differences between AA-AF and SA-AF, PH-AF, and non-PH-AF groups (aSHR: 0.87–1.01 vs. AA-AF). All AF groups showed a significantly higher aSHR compared with no AF. Conclusion Ischemic stroke risk in patients with AA-AF incidentally detected in primary care is far from benign, and not less than incident AF presenting clinically in general practice or hospital. This provides justification for identification of previously undetected AF, e.g., by opportunistic screening, and subsequent stroke prevention with thromboprophylaxis, to reduce the approximately 10% of ischemic strokes related to unrecognized AF.

中文翻译：

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与其他临床表现相比，初级保健中偶然发现的无症状心房颤动中缺血性卒中的风险

背景 不确定在初级保健中偶然发现的无症状动态心房颤动 (AA-AF) 的卒中风险是否与初级保健或医院中的其他临床 AF 表现相当。方法 将来自英国初级保健临床实践研究数据链接的 22,035 例非瓣膜性 AF 患者的卒中风险与住院和死亡率数据相关联，与 23,605 例无 AF 对照（年龄和性别匹配 5:1 至 5,409 AA-AF患者）。事件 AF 包括 5,913 例症状性动态 AF (SA-AF)；4,989 名原发性和 5,724 名非原发性医院 AF 出院诊断（PH-AF 和非 PH-AF）；和 5,409 与 AA-AF。将 AA-AF 与 SA-AF、PH-AF、非 PH-AF 和无 AF 的 3 年内缺血性卒中调整亚风险比 (aSHR) 进行了比较，将死亡率作为竞争风险并根据缺血性卒中风险因素进行调整。结果 49,544 人年发生 AF 的患者中发生了 1,026 次缺血性卒中（粗发病率：2.1 次缺血性卒中/100 人年）。3 年以上的缺血性卒中 aSHR 显示​​ AA-AF 和 SA-AF、PH-AF 和非 PH-AF 组之间没有差异（aSHR：0.87-1.01 与 AA-AF）。与无 AF 相比，所有 AF 组的 aSHR 均显着升高。结论 初级保健中偶然发现的 AA-AF 患者的缺血性卒中风险远非良性，且不低于在全科或医院临床上出现的新发 AF。这为识别先前未检测到的 AF 提供了依据，例如，通过机会性筛查，以及随后通过血栓预防来预防中风，