Emboli may originate as cardiac thrombi, especially in the following conditions: Atrial fibrillation Rheumatic heart disease (usually mitral stenosis) Post-myocardial infarction Vegetations on heart valves in bacterial or marantic endocarditis Prosthetic heart valves Mechanical circulatory assist devices (eg, left ventricular assist device, or LVAD [2]) Other sources include clots that form after open-heart surgery and atheromas in neck arteries or in the aortic arch.