Endocarditis is an inflammation of the inner layer of the heart. Endocarditis most often affects the heart valves. The heart valves are a part of the human body that does not get blood. This is odd because they are a part of the heart itself. Because of this, if one of the valves gets infected with a bacteria or protozoa, the body can not defend itself against that bacteria. This can cause the valve to not work the way it should.