Atrial fibrillation (AF) is the significant risk factor of ischemic stroke with incidence about 20% of all ischemic strokes. The undiagnosed AF in cryptogenic stroke patients could be present but not revealed by rutinne ECG.

The subcutaneous Insertable Cardiac Monitor - Reveal® XT ICM, which provides long-term monitoring ( for 3 years), in selected stroke and TIA population on the basis of age, stroke etiology, and prescreening for cardiac arrhythmias helps to increase a detection of AF to 16.7% (range, 14.3% to 20.0%) in compare to ambulatory ECG detection of AF 6.4% (range, 5.3% to 9.0%). The AF detection after stroke and TIA strategically changes the therapeutic approach. In correlation with mentioned above the incidence of both specific genetic markers of AF and occurance of AF in this population and healthy volunteers are interesting.

Inclusion Criteria:

• 1. Cryptogenic stroke or TIA within 72 h of onset symptoms according to the criteria for the Trial of Org 10172 in Acute Stroke Treatment (TOAST ) 2. National Institute of Health Stroke scale (NIHSS ) score ≤ 15 3. Modified Rankin Scale (mRS ) score ≤ 3 4. Ability and willingness of patients or their relatives or legal representatives to understand study instructions both verbal and written in accordance with ICH GCP and legislation applicable in the Slovak Republic

Exclusion Criteria:

• 1. Known etiology of stroke or TIA 2. Untreated hyperthyreosis 3. Myocardial infarct within 1 month of onset stroke or TIA 4. Coronary bypass within 1 month of onset stroke or TIA 5. Valvular disease requiring urgent surgery 6. Documented atrial fibrillation or flutter . 7. Patent Foramen Ovale (PFO) 8. Permanent indication to oral anticoagulation therapy 9. Long-term steroid therapy > 30 days 10. Participation in another clinical trial oriented to experimental pharmacologic therapy .

  11. Chronic inflammatory disease ( rheumatoid arthritide, IBD (Inflammatory bowel diseases ), lupus, vasculitis) 12. Severe co-morbidity not likely to complete to follow-up one year 13. Pregnant and breastfeeding women 14. Indication to pacemaker implantation, implantable cardioverter defibrillator (ICD) or Cardiac Resynchronization Therapy IPG or ICD implantation 15. Unabillity provide or unconsent with requiring protocol procedures

Patients with stroke or TIA confirmed by neurologist within 72 hours of onset symptoms