Incidence of Silent Atrial Fibrillation in Patients With Clinically Silent Brain Ischemic Lesions

Inclusion Criteria: * Age * ≥ 65 years * ≥ 50 years AND one the following: * NT-proBNP \>400 pg/mL * Left atrial ventricular index \>42 ml/m2 or left atrial diameter \>46 mm * Covert infarctions with cortical involvement in more than one vascular territory (left carotid territory, right carotid territory, vertebrobasilar territory) * Written informed Consent * Any clinically silent ischemic lesions of the brain parenchyma detected on neuroimaging defined according to established criteria as either: * Diffusion weighted imaging (DWI) positive lesions: Focus of restricted diffusion (high DWI signal and low apparent diffusion coefficient value) occurring in either white or gray matter, located in the cerebrum, cerebellum, or brain stem AND not satisfying the diagnostic criteria for multiple sclerosis OR * Cavitatory Lesions: ≥ 3 mm in size that follow cerebro-spinal fluid on all sequences that are slit or wedge shaped with an irregular margin AND NOT longitudinally aligned with perforating vessels or with a multiple, bilateral symmetrical distribution OR * T2 weighted (T2W) hyperintense/T1 weighted (T1W) hypointense lesions: * Focal lesion with high T2W signal and low T1W signal that have prior evidence of restricted diffusion; OR * Present within cortical gray matter or deep gray matter nuclei OR * A lesion that is new, compared with an MRI performed within 3 months OR * T2W hyper/T1W hypointense lesions in the white matter, which are discontinuous but associated with the classic confluent periventricular T2 intense change of leukoaraiosis (Fazekas ≥2) AND NOT satisfying the diagnostic criteria for multiple sclerosis or with a significant patient history of severe trauma, radiation, drug toxicity, or carbon monoxide poisoning Exclusion Criteria: * History of AF or atrial flutter * Patients with a history of symptoms compatible with an AIS, covert neurological deficits are allowed. * Cardiac implantable electronic devices (pacemaker, implantable cardiac defibrillator (ICD), implantable cardiac monitor (ICM)) * Indication for cardiac implantable electronic device implantation (pacemaker, ICD, ICM) * History of or indication for major cardiac surgery or transcutaneous aortic valve implantation * Indication for permanent oral anticoagulation * Contraindication for permanent oral anticoagulation * Projected life expectancy of less than 2 years * Active intra- or extracranial high-grade malignancy * Patient is already included in another clinical trial that will affect the objectives of this study * Patient's lack of accountability, inability to appreciate the nature, meaning and consequences of the study and to formulate his/her own wishes correspondingly * Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. * Known or suspected non-compliance, drug or alcohol abuse