A comparison of Atrial Fibrillation Detection Strategies After Ischemic Stroke-A Retrospective Study

Objective of this retrospective study was to determine if long-term continuous cardiac monitoring with Implantable loop recorder (ILR) in patients with Cryptogenic strokes or TIA is superior at detecting Atrial Fibrillation (AF) than 30-day Event Monitor (EM) and 48-hour Holter Monitor (HM). Furthermore, we aimed to deduce if uncovering AF leads to lower risk of future ischemic strokes, or reduction in mortality. In 20%-30% cases, the cause of stroke remained unexplained after diagnostic workup which has led to coining of the term, Cryptogenic Stroke (CS). Undiagnosed AF is a prime suspect in CS, but guidelines do not recommend initiation of anticoagulation unless AF has formally been detected. IRB approved retrospective study included patients with at least 1 episode of ischemic stroke or TIA without identifiable cause and was monitored with either HM, EM or ILR to diagnose any undiscovered AF. All patients (n = 531) had at least 1 year, and up to 3 years, of follow-up after device placement. Chi-Squared analysis and Multivariable logistic regression demonstrated no statistically significant difference among 3 devices for detection of AF within 1 month of index stroke but a significant difference in AF detection was observed at 6, 12 and 24 months. Cox proportional hazard model showed device type had no significant impact on secondary outcomes: Subsequent ischemic stroke or TIA, Initiation of anticoagulation, Mortality and Incidence of major bleeding. Despite the superiority of AF detection by ILR, it is not superior to HM or EM in lowering the risk of subsequent stroke or TIA, or in reducing mortality.