Recurrent vascular events and mortality outcomes in patients with known atrial fibrillation, compared to atrial fibrillation detected early after stroke.

Introduction: Atrial fibrillation (AF) detected after stroke (AFDAS) may represent a distinct clinical entity to that of known AF (KAF). However, there is limited long-term outcome data available for patients with AFDAS. More information regarding prognosis in AFDAS is required to inform future trial design in these patients.

Patients and methods: We used data (2015-2019) from a national prospective stroke registry of consecutive patients with acute ischaemic stroke and AF. AFDAS was defined as a new diagnosis of AF after stroke detected on electrocardiograph or cardiac monitoring. The co-primary endpoints were: (1) all-cause mortality; (2) recurrent major adverse cardiovascular events (MACE) at 3 years. Secondary endpoints were: (1) recurrent stroke; (2) functional outcome at discharge; (3) presence of co-existing stroke mechanisms.

Results: 583 patients were included. After a median follow-up of 2.65 years (cumulative 1064 person-years) 309 patients died and 23 had recurrent MACE. Compared with AFDAS, KAF was associated with a higher risk of all-cause mortality (adjusted Hazard Ratio (aHR) 1.56, 95% CI 1.12-2.18), a higher prevalence of co-existing stroke mechanisms (adjusted odds ratio (aOR) 2.28, 95% CI 1.14-4.59), but not poor functional outcome (aOR 1.61, 95% CI 0.98-2.64). A trend towards a higher risk of MACE was observed in patients with KAF, but this was limited by statistical power (aHR 2.90, 95% CI 0.67-12.51). All 14 recurrent strokes occurred in the KAF group (Log-rank p = 0.03).

Discussion and conclusion: These data provide further evidence that AFDAS differs to KAF with respect to risk of recurrent stroke, MACE, and all-cause mortality.