Atrial Fibrillation Detected by Single Time-Point Handheld Electrocardiogram Screening and the Risk of Ischemic Stroke

Objective We evaluated stroke risk in patients with single time-point screen-detected atrial fibrillation (AF) and the effect of oral anticoagulants (OACs). Methods Consecutive patients aged >= 65 years attending medical outpatient clinics were prospectively enrolled for AF screening using handheld single-lead electrocardiogram (ECG; AliveCor) from December 2014 to December 2017 (NCT02409654). Repeated screening was performed in patients with >1 visit during this period. Three cohorts were formed: screen-detected AF, clinically diagnosed AF, and no AF. Ischemic stroke risk was estimated using adjusted subdistribution hazard ratios (aSHRs) from multivariate regression and no AF as reference, and stratified according to OAC use. Results Of 11,972 subjects enrolled, 2,238 (18.7%) had clinically diagnosed AF at study enrollment. The yield of screen-detected AF on initial screening was 2.3% ( n =223/9,734). AF was clinically diagnosed during follow-up in 2.3% ( n =216/9,440) and during subsequent screening in 71 initially screen-negative patients. Compared with no AF, patients with screen-detected AF without OAC treatment had the highest stroke risk (aSHR: 2.63; 95% confidence interval: 1.46-4.72), while aSHR for clinically diagnosed AF without OAC use was 2.01 (1.54-2.62). Among screen-detected AF, the risk of stroke was significantly less with OAC (no strokes in 196 person-years) compared with those not given OAC (12 strokes in 429 person-years), p =0.01. Conclusion The prognosis of single time-point ECG screen-detected AF is not benign. The risk of stroke is high enough to warrant OAC use, and reduced by OAC.