Abstract Number: Esoc2026lt62 Lt62 - Detection of Silent Atrial Fibrillation After Ischemic Stroke (Saffo) Guided by Implantable Loop Recorder: Multicentre Trial on Patients With First Atherothrombotic or Lacunar Ischemic Stroke

Abstract Background and aims Atrial fibrillation (AF) is a major cause of ischemic stroke (IS) and is often paroxysmal and asymptomatic, leading to underdetection with conventional monitoring.The benefit of prolonged rhythm monitoring after noncardioembolic IS remains uncertain.The SAFFO study evaluated whether long-term continuous monitoring with an implantable loop recorder(ILR) improves detection of silent AF compared with standard care in patients with first-ever atherothrombotic or lacunar stroke. Methods SAFFO was a prospective, multicenter, randomized, controlled PROBE-design trial.Adults aged ≥60 years with a first IS due to large-artery atherosclerosis or small-vessel disease and no prior AF were randomized 1:1 to ILR monitoring plus standard care or standard care alone.The primary outcome was AF detection at 12 months. Secondary outcomes included AF detection up to 36 months, initiation of oral anticoagulation, and recurrent stroke. Results Among 317 patients (mean age 71.2 years;25.6% women), AF was detected more frequently with ILR than standard care at 12 months (13.1% vs. 3.3%; HR 4.28; 95% CI 1.59–11.53; P=0.002).At 36 months, cumulative AF detection was 19.7% versus 6.5% (HR 3.30; 95% CI 1.60–6.83; P=0.0006). Monitoring limited to 30 days would have missed most AF episodes.Most AF was asymptomatic and paroxysmal, with similar detection across index stroke subtypes.Anticoagulation was initiated more often in the ILR group, while stroke recurrence did not differ between ILR and control groups. Conclusions Long-term ILR monitoring substantially increases detection of subclinical AF after atherothrombotic and lacunar IS, supporting the multifactorial nature of stroke mechanisms and raising the question of its appropriateness in selected patients. Conflict of interest