Atrial Fibrillation Detected by Handheld ECG and Ischemic Stroke Risk in a 55- to 64-Year-Old Chinese Population

Atrial fibrillation (AF) screening is recommended at age ≥65 years, but the age threshold in Asians is uncertain because of higher ischemic stroke risk <65 years. This study evaluated AF screening yield in a Chinese population aged 55 to 64 years, comparing stroke risk of those with and without AF, and the effect of oral anticoagulants (OAC). Patients aged 55 to 64 years attending Hong Kong outpatient clinics underwent opportunistic handheld electrocardiogram screening. Repeat screening was performed if >1 clinic visits. Crude incidence rate ratios of ischemic stroke were determined and compared between 3 cohorts: screen-detected AF; clinically diagnosed AF; and no AF. Ischemic stroke risk for all AF categories was compared with individuals without AF, using adjusted subdistribution HRs (aSHRs) accounting for death as a competing risk. Of 3,926 subjects screened, 338 (8.6%) had known AF, and 3,588 had no AF history. New AF yield was 0.8% (28/3,588). AF was clinically diagnosed during follow-up in 2.3% (n = 82) and during subsequent screening in 7 subjects. Of 35 subjects with screen-detected AF, 26 (74%) had ≥1 non-age, non-sex risk factor for stroke, mean age 60.8 ± 2.5 years, and mean CHA2DS2-VASc score 1.9 ± 1.4. At a median follow-up of 5.0 years, 2 patients (6%) with screen-detected AF experienced ischemic stroke, both with ≥1 non-age, non-sex risk factor. AF exposure without OAC treatment was associated with highest risk of ischemic stroke (aSHR: 3.4 [1.3-8.5]). OAC treatment had similar low ischemic stroke risk as no AF. Although diagnostic yield of AF screening in Chinese patients aged 55 to 64 years is low, those with AF are at increased stroke risk and may warrant being on anticoagulation.