Heart valve infection, illustration. This is an example of infective endocarditis of the mitral valve caused by fungal infection. The valve surface shows dull gray deposits of thromboses (blood clots) with red blood cells and fibrin. Underlying tissues of the valve and the left atrium are ulcerated with necrotic inflammation. Valve function is impaired with vascular insufficiency and stenosis (narrowing) and may produce emboli affecting the aorta. Although rare and also caused by bacterial infections, satisfactory treatment with medication and/or surgery is difficult. From Bollinger, O. 1901 Atlas und Gundriss der Pathologischen Anatomie, vol 1. Lehmann, Munich.