---
title: Infective endocarditis
description: What infective endocarditis is, why it develops, how it is recognised, which treatment approaches clinical guidelines describe and when urgent help is needed.
type: disease
aliases:
  - IE
  - bacterial endocarditis
sources:
  - tier: guideline
    org: esc
    title: 2023 ESC Guidelines for the management of endocarditis
    year: 2023
    doi: 10.1093/eurheartj/ehad193
    url: https://doi.org/10.1093/eurheartj/ehad193
  - tier: guideline
    org: minzdrav-rf
    title: Инфекционный эндокардит и инфекция внутрисердечных устройств
    year: 2025
    doi: 10.15829/1560-4071-2026-6853
    url: https://cr.minzdrav.gov.ru/view-cr/54_3
sources_checked: 2026-10-11
review: null
---

Infective endocarditis is an infectious and inflammatory disease of the inner lining of the heart (the endocardium) on the valves and the heart walls, and of artificial devices inside the heart. It is caused by bacteria or fungi.<Cite n={2} /> Growths called vegetations form on the affected structures; the infection destroys the nearby heart tissue, and vegetations break off easily.<Cite n={2} />

<Diagram name="infective-endocarditis">
  <p slot="normal">
    This is a valve without infection: the leaflets are intact, there are no vegetations on them,
    and blood does not flow backwards. Infective endocarditis affects the endocardium of the
    valve structures.<Cite n={2} />
  </p>
  <p slot="disease">
    In endocarditis a vegetation made of fibrin, microorganisms and blood cells grows on a
    leaflet. The infection destroys tissue, even perforating or tearing off leaflets, and the
    valve starts to let blood flow backwards (regurgitation). Vegetations or pieces of them break
    off easily and are carried away with the blood.<Cite n={2} />
  </p>
</Diagram>

## Why it happens

<Patient>

Endocarditis is most often caused by staphylococci, streptococci and enterococci.<Cite n={2} /> Bacteria get into the blood, for example, during many medical procedures.<Cite n={2} />

The risk is highest in people who have had endocarditis before and in people with artificial heart valves.<Cite n={1} /> Other risk factors include valve disease, congenital heart disease, devices implanted in the heart, catheters in large veins, injecting drugs and a weakened immune system.<Cite n={2} />

</Patient>

<Student>

Typical pathogens are Gram-positive cocci: S. aureus (17–43%), coagulase-negative staphylococci (7–13%), enterococci (9–16%) and streptococci, including S. bovis (2–10%) and viridans group streptococci (9–26%).<Cite n={2} /> Bacteraemia occurs with many invasive medical procedures.<Cite n={2} /> Vegetations grow as fibrin, microorganisms and blood cells involved in the inflammation are deposited on their surface. Active infection spreads to the adjacent connective tissue of the heart and destroys it, causing perforation and tearing of valve leaflets and rupture of chordae tendineae, followed by heart failure.<Cite n={2} /> Vegetations or their fragments are loosely attached to the endocardium and break off easily, so more than a third of patients develop embolic complications.<Cite n={2} />

The estimated incidence is 13.8 cases per 100 000 people per year.<Cite n={1} /> The highest risk is in patients with a previous history of IE and in patients with surgically or transcatheter implanted prosthetic valves.<Cite n={1} /> The Russian Ministry of Health guideline lists cardiac risk factors (previous IE, valvular heart disease, prosthetic heart valves, central venous or arterial catheters, implanted cardiac devices, congenital heart disease) and non-cardiac ones (central venous catheters, injecting drug use, immunosuppression).<Cite n={2} />

</Student>

<HeartModel highlight={['mitral-valve', 'aortic-valve', 'tricuspid-valve', 'pulmonary-valve']} />

## Symptoms

<Patient>

The most common signs are a raised temperature and a new heart murmur that the doctor hears.<Cite n={[1, 2]} /> There may also be chills, weight loss, breathlessness and, less often, swollen legs.<Cite n={2} />

</Patient>

<Student>

In the EURO-ENDO registry the most frequent clinical presentations were fever (77.7%), a cardiac murmur (64.5%) and congestive heart failure (27.2%); embolic complications were detected in 25.3% of patients.<Cite n={1} /> The Russian Ministry of Health guideline also lists chills, splenomegaly, weight loss, breathlessness and, less often, lower-limb oedema.<Cite n={2} /> A new murmur of valvular regurgitation is characteristic: systolic when the mitral valve is involved, early diastolic when the aortic valve is involved.<Cite n={2} />

</Student>

## How it is diagnosed

<Patient>

The main tests are blood cultures, to find the organism, and a heart ultrasound (echocardiography).<Cite n={[1, 2]} /> The ultrasound is done through the chest wall and also through the oesophagus.<Cite n={2} />

</Patient>

<Student>

Positive blood cultures remain the cornerstone of IE diagnosis; echocardiography is the first-line imaging technique.<Cite n={1} /> According to the Russian Ministry of Health guideline, the first step is microbiological (culture) testing of the blood for sterility together with echocardiography, both transthoracic and transoesophageal; the diagnosis is made using the modified Duke criteria (2023).<Cite n={2} /> Clinical, microbiological and imaging findings have been integrated in the modified Duke criteria since 2000.<Cite n={1} />

Echocardiography has limited sensitivity at early stages, especially in prosthetic valve endocarditis and endocarditis of pacemaker and ICD leads: in these cases it is non-diagnostic in 30% of cases.<Cite n={2} />

</Student>

## How it is treated

<Patient>

The guidelines describe two main approaches: antibiotic treatment and heart surgery.<Cite n={[1, 2]} /> Decisions are made by a team of doctors from different specialties, the "Endocarditis Team".<Cite n={1} />

For people at increased risk of endocarditis, the guidelines advise cleaning the teeth twice a day, keeping the skin clean and, with a fever of unknown cause, telling the doctor that they are at risk.<Cite n={1} /> Antibiotics before dental procedures are recommended for people at high risk; for people at intermediate risk they are not routinely given, and the decision is made individually.<Cite n={1} />

</Patient>

<Student>

The treatment sections of both guidelines cover antibiotic therapy and surgical treatment; the 2023 ESC guideline includes recommendations on outpatient parenteral or oral antibiotic therapy and on the timing of surgery.<Cite n={[1, 2]} /> Diagnosis and management are led by an Endocarditis Team that must meet on a frequent basis.<Cite n={1} /> When there is failure to respond to antibiotic therapy or there are complications related to valvular tissue destruction, the Referring Centre should consult the Heart Valve Centre.<Cite n={1} />

Antibiotic prophylaxis is recommended in patients at high risk of IE undergoing at-risk dental procedures; in patients at intermediate risk it is not routinely recommended.<Cite n={1} /> General prevention measures for patients at high and intermediate risk include twice-daily tooth cleaning.<Cite n={1} />

</Student>

## When to call an ambulance

Pieces of vegetations can break off and block blood vessels: embolic complications occur in more than a third of patients.<Cite n={2} /> Destruction of the valve leads to heart failure.<Cite n={2} /> Such emboli can cause, for example, a brain infarction (ischaemic stroke) or a myocardial infarction.<Cite n={2} /> Call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK) if there are signs of a stroke. As with any heart condition, call an ambulance for fainting, chest pain or severe breathlessness: this is the site's general safety rule, repeated at the bottom of every page.

If a person at risk of endocarditis (for example, with a prosthetic valve or previous endocarditis) develops a fever with no clear cause, they should tell the doctor that they are at risk.<Cite n={1} />

<Quiz />