by Scholten A


Non-infective endocarditis is the growth of blood clots on the valves and inner walls of the heart. They can damage the heart. The growths can also break off and block blood flow in the brain, lungs, or other areas of the body.


This condition is often caused by health problems that:

  • Let the blood clot too easily
  • Damage areas of the heart valve—such as an illness or birth defect
Blood Flow through the Heart
Nuclus factsheet image
Copyright © 2002 Nucleus Communications, Inc. All rights reserved.

Risk Factors

Non-infective endocarditis is most common in those aged 30 to 70 years old. Things that raise the risk are:


Endocarditis itself does not cause symptoms. Growths that have broken off can block the flow of blood. This can cause symptoms. Examples are symptoms of a heart attack or stroke.


The doctor will ask about symptoms and past health. A physical exam will be done. The doctor may test for endocarditis—if there have been problems with blood clots.

Diagnosis is based on tests, such as:

  • Blood tests—to check for infection or clot issues
  • Echocardiogram—to view heart and heart valves
  • Biopsy—the growth is removed and tested


The goal is to stop the growth of more clots. This will help to prevent problems like a stroke. Medicine can make it harder for blood to clot. This can stop clots, but also increase the risk of bleeding.

Problems that raise the risk of blood clots will also need to be treated.


There are no known guidelines to prevent this condition.


American Heart Association 

National Heart, Lung, and Blood Institute 


Health Canada 

Heart and Stroke Foundation of Canada 


Bussani R, De-Giogio F, et al. Overview and comparison of infectious endocarditis and non-infectious endocarditis: a review of 814 autoptic cases. In Vivo. 2019; 33(5): 1565–1572.

Nonbacterial thrombotic endocarditis (NBTE). EBSCO DynaMed website. Available at: Accessed September 1, 2021.

Noninfective endocarditis. Merck Manual Professional Version website. Available at: Accessed September 1, 2021.

Revision Information

  • Reviewer: EBSCO Medical Review Board Nicole Meregian, PA
  • Review Date: 07/2021
  • Update Date: 09/01/2021