Inclusion Criteria- Patients must have had an episode of symptomatic Transient ischemic attack (TIA) or episode of ischemic stroke.
- Ischemic stroke is defined as an episode of transient or neurological dysfunction caused by focal brain or retinal ischemia with recent infarction on imaging
- A TIA is defined as transient episode of neurologic dysfunction typically lasting less than one hour caused by focal brain or retinal ischemia without recent infarction on imaging.
Exclusion Criteria- Known etiology of TIA or ischemic stroke
- TIA or stroke caused by spinal ischemia
- TIA only presenting with non-localising symptoms
- Uncertainty about the diagnosis of TIA because of unclear clinical symptoms
- Myocardial infarction <6 months before stroke
- Coronary Artery Bypass Grafting <6 months before stroke
- Severe valvular heart disease
- Documented history of atrial fibrillation or atrial flutter
- Permanent indication for oral anticoagulation at enrolment
- Patient has permanent OAC contraindication
- Patient is included in another randomized trial
- Left ventricular aneurysm on echocardiography
- Thrombus on echocardiographyRenal dysfunction (creatinine clearance <30 mL/min/1.73m2)
- Patient has life expectancy of <1 year
- Patient is not willing to sign the informed consent form
- Patient is <18 years of age
- Patient is considered an incapacitated adult
- Patient is not in possession of a smartphone with Android Operating System (OS) or iOS.