Infective endocarditis (IE) is defined as an infection of the endocardial surface of the heart (see the image below), which may include one or more heart valves, the mural endocardium, or a septal defect. Its intracardiac effects include severe valvular insufficiency, which may lead to intractable congestive heart failure and myocardial abscesses. If left untreated, IE is generally fatal.