The most commonly diseased valves are the mitral and aortic valves. Infective endocarditis is caused when the lining of the heart is infected by microorganisms that form redundant organisms. Because microorganisms often follow the blood flow from the high-pressure cavity to the low-pressure cavity, through the valve orifice, for patients with valve disease, because the mitral valve, aortic valve closure insufficiency caused by the low-pressure cavity in the blood flow of the blood flow of the perfusion is relatively small, for the growth of microorganisms and deposition is favorable, so the microorganisms in the two major valves to stay, deposition, resulting in microbial infections and the formation of redundant organisms, so the two parts of the heart in these two areas is the most common.