Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source during 3 Years of Prolonged Monitoring with an Implantable Loop Recorder.

BACKGROUND: Undocumented atrial fibrillation (AF) is suspected as a main stroke cause in patients with embolic stroke of undetermined source (ESUS), but its prevalence is largely unknown. This prospective study therefore aimed at delineating the prevalence of AF in patients with ESUS using continuous cardiac monitoring by implantable loop recorder (ILR) with daily remote interrogation over a period of 3 years and its clinical consequences, including recurrent stroke. METHODS: In consecutive patients with an ESUS diagnosis after complete work-up, an ILR was implanted and followed by daily remote monitoring until AF was detected or a follow-up of at least 3 years was completed. Additionally, the ILR was interrogated in-hospital in 6-month intervals. RESULTS: A total of 123 patients (74 male, mean age 65 ± 9 years) were enrolled and completed the 3 years study period. AF was detected in 51 patients (41.4%). In 43 of the 51 AF positive patients (84%) oral anticoagulation was established. Recurrent strokes occurred in 18 patients (14.6%) of this ESUS population, 9 of these patients being AF positive (17.6% of the AF-positive patients) and 9 being AF negative (12.5% of AF-negative patients). Patients with AF were slightly older than patients without AF (63.1 ± 8.8 vs. 67.5 ± 9.6 years, p = 0.12). Other parameters such as CHA2DS2-VASc score, infarct localization, micro- and macroangiopathy, carotid or aortic plaques, or stroke recurrence were not significantly different between groups. CONCLUSION: In ESUS patients, early implantation of an ILR with cardiac monitoring and remote transmission over a 3-year period detected AF in 41.4% and resulted in oral anticoagulation in 84% of these patients.

Detection of atrial fibrillation in patients with embolic stroke of undetermined source by prolonged monitoring with implantable loop recorders.

Recently, the clinical entity embolic stroke of undetermined source (ESUS) has been defined for patients with ischemic strokes, where neither a cardioembolic nor a non-cardiac source can be detected. These patients may suffer from asymptomatic atrial fibrillation (AF), terminating spontaneously and thus eluding detection. Implantable loop recorders (ILR) with automatic AF detection algorithms can detect short-lasting, subclinical AF. The aim of this study was to prospectively assess and predict AF detection in patients with ESUS using ILR with daily remote interrogation. Patients with acute ESUS received an ILR, were seen every 6 months and additionally interrogated their ILR daily using remote monitoring. The incidence of AF detection was assessed and parameters which might predict AF detection (clinical and from magnetic resonance tomography) were analysed. ILR implantation was performed in 123 patients on average 20 days after stroke. During a mean follow-up of 12.7±5.5 months, AF was documented and manually confirmed in 29 of 123 patients (23.6 %). First AF detection occurred on average after 3.6±3.4 months of monitoring. Patients with AF were on average older, had a higher CHA2DS2-VASc score and more often cerebral microangiopathy. In conclusion, AF can be documented in approximately 25 % of patients with the diagnosis of ESUS after careful work-up within a year of monitoring by an ILR and daily remote interrogation. This had important therapeutic consequences (initiation of anticoagulation for secondary stroke prevention) in these patients.