Atrial Fibrillation and Stroke Risk: What You Need to Know

Blood pooling in the fibrillating atria can clot. If a clot travels to the brain, a stroke results. AF-related strokes tend to be more severe, more disabling, and more likely to be fatal than strokes from other causes. Despite this, patients frequently express greater concern about bleeding from anticoagulation than about the stroke risk itself — an imbalance that careful risk discussion with a cardiologist should correct.

Warfarin was used for over 60 years but carries significant limitations — dietary restrictions, drug interactions, and the need for regular INR monitoring. Asian populations, including Singaporeans, demonstrate higher bleeding risks on warfarin, and studies show suboptimal INR control: approximately 58% time-in-range for Chinese patients and under 50% for Indian patients. Over the past decade, newer oral anticoagulants (NOACs) — including apixaban, rivaroxaban, edoxaban, and dabigatran — have become the standard of care. They require no blood test monitoring, have lower rates of intracranial haemorrhage, and demonstrate superior safety in Asian populations.

Traditional guidelines supported continuing anticoagulation even after successful rhythm-restoring ablation, for patients with elevated stroke risk scores. The 2025 ALONE-AF trial examined 840 patients who remained arrhythmia-free for at least one year after ablation. Those who stopped anticoagulation experienced no significant difference in stroke or systemic embolism rates compared to those who continued — and had substantially lower bleeding rates. This suggests that discontinuation may be a reasonable option for carefully selected low-to-intermediate-risk patients who are arrhythmia-free after ablation. However, patients with CHA₂DS₂-VASc scores above 3 or a prior stroke history should continue anticoagulation — the evidence does not support discontinuation in these groups. These decisions require careful individual risk assessment.

For patients who cannot tolerate long-term anticoagulation due to serious bleeding, frequent falls, or unpredictable INR instability, left atrial appendage closure (LAAC) offers an alternative. This minimally invasive procedure seals the left atrial appendage — the small pouch in the heart where most AF-related clots originate. It is performed through a small puncture at the groin, requires only short-term antiplatelet therapy after the procedure, and is increasingly accessible in Singapore. LAAC is generally reserved for anticoagulation-intolerant patients rather than as a first-line alternative to medication.