230 Unexpected low prevalence of atrial fibrillation in cryptogenic ischemic stroke: a prospective continuous monitoring study

Introduction Ischemic stroke (IS) is a frequent pathology, burdened by high rate of recurrence and significant morbidity and mortality. There are several causes of IS, affecting prognosis, outcomes and management, but in many cases the etiology remains undetermined despite comprehensive research. We hypothezised that atrial fibrillation (AF) was largely involved in this pathology but was underdiagnosed by standard methods. The aim of this study was to determine the incidence of AF in cryptogenic IS, by using continuous monitoring of the heart rate over several months. The secondary objective was to test the predictive value of atrial vulnerability study towards spontaneous AF. Methods and results We prospectively enrolled 24 patients under 75 years: 15 men and 9 women of mean age 48.8± 13.6 years who experienced cryptogenic IS presumed of cardioembolic mechanism within the last 4 months. Any cause of IS was excluded by normal 12-lead ECG, 24-hour Holter monitoring, echocardiography, cervical Doppler, haematological and inflammatory tests. All patients underwent electrophysiological study. 7 patients (29.2%) had inducible arrhythmia during programmed atrial stimulation and 9 (37.5%) had a latent vulnerability index (LVI) Conclusion This study shows that contrary to what was expected, AF does not appear to be a common pathology in patients under 75 years with unexplained IS. The use of ILR should not be generalized in the systematic assessment of these patients because of its unprofitability. Finally this study attests the poor value of atrial vulnerability study for predicting spontaneous AF in such patients.