For patients with atrial fibrillation who occupy the uncertain middle ground of stroke risk, medicine has long offered ambiguity where clarity was needed. The SINGLE-AF trial, presented at the European Society of Cardiology Congress and published in the New England Journal of Medicine, now offers the first randomized evidence that this borderline population benefits meaningfully from modern blood thinners — cutting adverse events by nearly two-thirds without raising the bleeding risks that once justified hesitation. It is a finding that may quietly shift millions of clinical conversations from