Endocarditis occurs when the inner lining of the heart (endocardium) becomes infected by bacteria that damages the heart valves, which can cause strokes and affect other organs in the body. In some cases, this happens slowly, while in others it comes on very quickly—subacute bacterial endocarditis versus acute endocarditis. Individuals at increased risk of endocarditis include those who have heart valve disease or an artificial heart valve, those with pacemakers, intravenous drug abusers, and patients born with certain types of heart defects. All patients will require treatment with high doses of antibiotics; in addition, surgery will be required to repair or replace damaged heart valves. See more about Endocarditis treatment.