 A stroke is defined as the sudden onset of a focal neurologic deficit, from a nontraumatic cause, in a location consistent with the territory of a major cerebral artery and categorized as either ischemic, hemorrhagic, or unspecified. An imaging examination CR, MRI will be recommended. A TIA is defined according to current standard criteria, i.e., as a stroke with relief of symptoms within 24 hours. Systemic cardioembolic events will be defined as an acute vascular occlusion of an extremity or organ, documented with imaging CT angiography, percutaneous interventional angiography, surgery, or autopsy. 