It is a term used to include subacute bacterial endocarditis as well as infection caused by viruses and fungi.
The causative organisms responsible for causing, infective endocarditis are streptococcus viridens, staphyllococci, Pneumococci, enterococci and fungi such as candida albicans. It also occurs as a late complication of valvular heart disease.
The organisms enter the blood stream from a local infection and tend to settle down and grow as vegetations on abnormal valves and areas of turbulance within the heart. These vegetations are abnormal outgrowths of microorganisms and deposits of fibrin and platelet thrombi at the sites of erosion of endocardium. They may invade adjacent issues like myocardium and aortic and mitral valves. They may also break off and form emboli which may travel to lungs, central nervous system, skin and spleen.