Endocarditis, or infective endocarditis, occurs when the inner lining of the heart (endocardium) or the heart’s valves become infected by bacteria or other germs. The bacteria that cause endocarditis typically spread through the bloodstream from the mouth, from infected foreign bodies such as needles, or from another part of the body to the heart.

An illustration showing bacterial growths on the heart's tissue.

Endocarditis is more likely to affect those who have a previously damaged heart valve, an artificial heart valve, or other heart disease or congenital defects. It can occur in people with otherwise healthy hearts as well.

Endocarditis may occur in children who are born with a heart defect. It tends to occur in association with some congenital heart conditions, such as aortic stenosis or patent ductus arteriosus (PDA), more than with others.

Routine antibiotic use prior to dental and gastrointestinal procedures (prophylaxis) is recommended in a few specific categories of congenital heart disease (CHD). Your doctor can help to determine whether you need to continue to take antibiotics. Additional antibiotic use for routine infections isn’t necessary to prevent the development of endocarditis.


The symptoms of endocarditis usually include the following:

  • A persistent or recurring high fever
  • Fatigue and shortness of breath
  • A skin rash

Progression and possible complications

If endocarditis isn’t treated, it can cause permanent damage to the heart valves and other heart structures. Heart valves that become damaged may not work as well as they should to keep blood moving through and out of the heart in one direction. A damaged valve may either allow blood to “leak" backward or become narrow, reducing blood flow through the heart and into the body. Ultimately, damage to the heart valves may lead to heart failure, a condition in which the heart cannot supply the body with enough blood. If the valve damage is too severe and can’t be repaired, the valve may have to be replaced surgically.

In rare situations, a piece of the infection (vegetation) may break off and travel to the lungs or other parts of the body. If it travels to the brain, it may result in a stroke.


Often, the infection (vegetation) may be seen by an echocardiogram. A more detailed echocardiogram, a transesophageal echocardiogram (TEE), may be helpful in making this diagnosis. However, an echocardiogram may not be able to see all infections. Multiple blood cultures are usually necessary to make the diagnosis of infective endocarditis. Prompt treatment with the proper antibiotics may reduce the possibility that endocarditis will cause significant damage to the heart valves. This may include a long course of antibiotics delivered via an IV. Surgical repair or replacement of damaged cardiac valves may also be necessary in severe cases.