Occult paroxysmal atrial fibrillation in non-cryptogenic ischemic stroke

Objective: To determine the prevalence and risk factors for paroxysmal atrial fibrillation (PAF) diagnosis in non- cryptogenic ischemic stroke (CIS) patients. Methods: In this pilot-prospective cohort study of non-CIS patients from September 2014 to September 2017, 53 patients were enrolled. 51/53 patients were implanted within 10 days of stroke onset with the Reveal LINQ insertable cardiac monitor and monitored until PAF detection or a minimum of 12 months. Inclusion required diagnosis of a non-AF stroke etiology, age ≥ 40, and either a virtual CHADS₂ score ≥ 3 or ≥ 2 PAF-related comorbidities. Results: Over a median monitoring period of 398 days, PAF was detected in 6/51 (11.8%) patients and anticoagulation was initiated in 5/6 (83.3%). Median time to PAF detection was 87 days (range 0–356 days). Median longest PAF episode was 96 min (range 1 to 1122 min), and 4/6 had multiple PAF recordings. Mean left atrial volume index was significantly higher in PAF patients (31.0 vs. 23.2 cc/m²; p = 0.04). Conclusion: Long-term monitoring of non-CIS patients detected PAF in a clinically relevant proportion of patients, resulting in stroke prevention therapy optimization. Further study to confirm these findings and refine the subset that would benefit from long-term cardiac monitoring is warranted.