Subclinical atrial fibrillation in embolic stroke of undetermined source: Management and stroke recurrence

Subclinical atrial fibrillation (SAF) represents the most prevalent underlying etiology detected after an embolic stroke of undetermined source (ESUS). Investigating SAF is strongly recommended during the diagnostic work-up. The efficacy of oral anticoagulant (OAC) therapy in reducing the risk of stroke recurrence post-SAF detection remains a conundrum. Thus, our study aimed to analyze the management of secondary antithrombotic prophylaxis and the rate of 12-month stroke recurrence in real-life ESUS patients. We retrospectively analyzed clinical, radiographic, and echocardiographic findings of patients with ESUS who underwent non-implantable 2-week electrocardiogram (ECG) monitoring after discharge. Episodes of SAF of any duration were considered diagnostic. Antithrombotic treatment at hospital discharge and after ECG monitoring, as well as 12-month recurrence, were registered. We compared the rate of stroke recurrence between patients with and without detection of SAF. One hundred and fifty-nine patients (75 females) with a median age of 73.5 (interquartile range [IQR] = 66.75 – 79) years represented the study population. At hospital discharge, 96.9% of patients received antiplatelet therapy as secondary antithrombotic prophylaxis. SAF was detected in 82 patients (51.5%), and OAC was prescribed in 98.6% of them. The median time from stroke onset to OAC prescription was 143 (IQR = 94 – 178) days. Overall, 12-month stroke recurrence occurred in eight patients (5%). The stroke recurrence rate was lower in patients prescribed OAC compared with those not prescribed it, although the difference was not significant (3.7% vs. 6.25%; P = 0.7202). In our study, OACs prescribed post-SAF detection in patients with ESUS reduced, but not significantly, the risk of stroke recurrence. Future research and prospective multicenter studies are warranted.