Infective endocarditis (IE) is an infection of the endocardial surface of the heart. It is characterized by one or more vegetations, which comprise a mass of platelets, fibrin, microorganisms, and inflammatory cells. IE primarily involves the heart valves (native or prosthetic). Other structures may also be involved, including the interventricular septum, the chordae tendineae, the mural endocardium, or intracardiac devices such as a pacemaker. The most common infective causes are bacterial; however, fungal endocarditis can be seen in patients who are immunocompromised. There is controversy about the existence of viral endocarditis. Valvular involvement in IE may lead to congestive heart failure, conduction abnormalities, and myocardial abscesses. Systemic complications in IE include embolization of both sterile and infected emboli, abscess formation, and mycotic aneurysms.