Most common cause of systemic thromboembolism is?

Most systemic emboli (80%) arise from intracardiac mural thrombi; two-thirds of these are associated with left ventricular infarcts and another 25% with dilated left atria (e.g.secondary to mitral valve disease). The remainder originate from aortic aneurysms, thrombi overlying ulcerated atherosclerotic plaques, fragmented valvular vegetations, or the venous system (paradoxical emboli); 10% to 15% of systemic emboli are of unknown origin.