The goal of this project is to extend the normal workup of patients with TIA with a thorough heart monitoring program. This includes 72-hours ambulatory electrocardiogram and insertion of an implantable loop recorder (ILR). The ILR is small device implanted in the subcutaneous tissue in the left thoracic region. The device continuously monitors for arrhythmias in a period up to 3 years. The 150 patients enrolled will also receive an ultrasound examination of the heart and arteries of the neck and a computed tomography scan of the heart. Lastly, biomarkers with known or suspected association with stroke and AF will be measured.