Introduction
Widely utilized cardiovascular and novel biomarkers have been suggested as the indicators of atrial fibrillation (AF) in patients with cryptogenic stroke. None of these are established in clinical praxis for selecting patients for prolonged cardiac rhythm monitoring. In the ongoing Nordic Atrial Fibrillation and Stroke study (NOR-FIB) we evaluate the incidence of AF in patients with cryptogenic stroke using insertable cardiac monitors, and measure the biomarker levels. The purpose of the interim analysis from our center was to evaluate whether clinically available biomarkers show association with AF detected before 6-month follow-up.

Method 
Blood samples from 53 patients were collected in the period from January 2017 to January 2019 in Østfold Hospital Trust with 40 patients reaching 6-month follow-up. TnI, BNP, fibrinogen, and D-dimer levels were measured. Mann-Whitney U test was performed to compare biomarker levels between patients with and without detected AF. Area under the receiver operating characteristic curve (AUC) was calculated for all of the tested biomarkers. Individual odds ratios (OR) were further computed.

Results
By 6 months, the AF detection rate was 27,5%. Mean (±SD) times to inclusion after the index event and to AF detection after inclusion were 9.3±3.4 days and 55.7±66.4 days respectively. Significant differences between the groups were found in TnI levels. The highest AUC was observed for TnI (0.742) as well as significant association with AF, OR 8.0 95% CI (1.65, 38.79). No significant association was found for the other biomarkers. 
 
Conclusion
New interim analyses with updated results including other biomarkers will be presented.

CLINICALLY AVAILABLE BIOMARKERS AS PREDICTORS OF ATRIAL FIBRILLATION IN PATIENTS WITH CRYPTOGENIC STROKE THE NORDIC ATRIAL FIBRILLATION AND STROKE STUDY (NOR-FIB)