Echocardiographic Predictors of Atrial Fibrillation

Stroke detected by CT (computertomography) or MRI (magnetic resonance imaging) that is not lacunar. (Lacunar is defined as a subcortical (this includes pons and midbrain) infarct in the distribution of the small, penetrating cerebral arteries whose largest dimension is ≤1.5 cm on CT or ≤2.0 cm on MRI diffusion images/<1.5 cm on T2 weighted MR images. The following are not considered lacunes: multiple simultaneous small deep infarcts, lateral medullary infarcts, and cerebellar infarcts.)

Absence of extracranial or intracranial atherosclerosis causing ≥50 percent luminal stenosis of the artery supplying the area of ischemia. Patients must undergo vascular imaging of the extracranial and intracranial vessels using either catheter angiography, CT angiogram (CTA), MR angiogram (MRA), or ultrasound, as considered appropriate by the treating physician and local principal investigator.

No major-risk cardioembolic source of embolism, including intracardiac thrombus, mechanical prosthetic cardiac valve, atrial myxoma or other cardiac tumors, mitral stenosis, myocardial infarction within the last 4 weeks, left ventricular ejection fraction <30 percent, valvular vegetations, or infective endocarditis).

No other specific cause of stroke identified, such as arteritis, dissection, migraine, vasospasm, drug abuse, or hypercoagulability. Special testing, such as toxicological screens, serological testing for syphilis, and tests for hypercoagulability, will be performed at the discretion of the treating physician and local principal investigator, if needed.