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

Abstract

Background: 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.

Objectives: 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).

Methods: 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.

Results: 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.

Conclusions: 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.