Inclusion Criteria:  Diagnosis of cryptogenic ischemic stroke or TIA The patient or its legal representative is willing to sign the informed consent  Exclusion Criteria:  History of AF or atrial flutter Life expectancy of less than one year Not qualified for ILR insertion Indication or contraindication for permanent oral anticoagulants (OAC) at enrolment Untreated hyperthyroidism Myocardial infarction or coronary bypass grafting less than one month before the stroke onset Presence of patent foramen ovale (PFO) and it is or was an indication to start OAC according to the European Stroke Organization guidelines Inclusion in another clinical trial that will affect the objectives of this study Not able to understand the Dutch language Patient or partner not in possession of a smartphone