If you have a fever that will not settle along with a known heart valve problem, a replacement valve, a pacemaker, or recent dental or surgical work — contact your GP urgently or go to A&E. Suspected infective endocarditis needs same-day medical assessment and blood tests in hospital. It is not a condition to investigate through an outpatient scan appointment.
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Infective endocarditis is an infection of the inner lining of the heart, usually affecting one or more of the valves. It is uncommon but serious, and it is treated as a medical emergency. Diagnosis rests on blood cultures and echocardiography together, carried out in hospital. If you have symptoms that suggest it, the right first step is urgent medical assessment — not a private scan.
The inside surface of the heart, including the valves, is lined with a thin layer of tissue called the endocardium. Infective endocarditis happens when bacteria — occasionally fungi — enter the bloodstream, settle on this lining and multiply there.
The infection forms a clump of bacteria, blood cells and debris called a vegetation, usually on a valve. This causes problems in three ways. It damages and destroys the valve itself, which can lead to sudden severe leaking. Fragments can break off and travel through the bloodstream to the brain, kidneys, spleen or limbs. And it seeds a continuous infection into the blood that antibiotics struggle to clear without prolonged treatment.
Healthy valves are relatively resistant. The infection more often takes hold where there is already something for bacteria to grip: a damaged or leaky valve, a replacement valve, a pacemaker or defibrillator lead, or a congenital heart abnormality.
The difficulty with infective endocarditis is that it often begins vaguely. Symptoms can build over weeks and are easily mistaken for a lingering viral illness:
Risk is higher if you have a replacement heart valve, have had endocarditis before, have a known valve problem such as aortic stenosis or significant mitral regurgitation, have a pacemaker or defibrillator, have certain congenital heart conditions, or inject drugs.
The combination that should always prompt urgent assessment is a persistent unexplained fever plus any of those risk factors. That combination is the reason this article exists.
Diagnosis is not made by a scan alone. It rests on two things being brought together, which is why it belongs in hospital.
Blood cultures. Several sets of blood samples are taken from different sites and at different times, then grown in the laboratory to identify the organism. This is the foundation of the diagnosis, and it also determines which antibiotics will work. Blood cultures must be taken before antibiotics are started, which is one reason self-treating a fever with leftover antibiotics can cause real harm.
Cardiac imaging. An echocardiogram looks for a vegetation, for new leaking around a valve, or for an abscess in the surrounding tissue.
Formal diagnosis uses a scoring framework — the modified Duke criteria, updated in 2023 by both the European Society of Cardiology and an international working group — which combines microbiological findings, imaging findings and clinical features. Cardiac CT and nuclear imaging have been added as recognised imaging routes alongside echocardiography, particularly where a replacement valve or device is involved.
Echocardiography is central to the imaging side of the diagnosis, and there are two forms of it.
A transthoracic echocardiogram scans through the chest wall. It is quick, comfortable and usually the first imaging test. It can show a vegetation if one is large enough, along with valve leaking and the effect on heart function.
A transoesophageal echocardiogram uses a probe passed down the oesophagus, which sits directly behind the heart. Because there is no chest wall or lung tissue in the way, it resolves much finer detail. It is more sensitive for small vegetations, for abscesses around a valve, and for anything involving a replacement valve or a pacemaker lead — situations where a normal transthoracic scan cannot be taken as reassurance.
A normal echocardiogram does not exclude infective endocarditis. If clinical suspicion remains high, the hospital team will repeat the imaging or escalate to a more detailed study. This is another reason a single outpatient scan is the wrong tool: the diagnosis often depends on repeating imaging as the picture evolves.
We have a settled position on this, and it is worth stating plainly because it runs against the commercial grain.
If someone contacts us with symptoms suggestive of infective endocarditis, we treat that as a red-flag medical problem rather than a routine outpatient scan request. The safe approach is to stand down the appointment and redirect the person for urgent medical assessment.
The reasoning is straightforward. A scan on its own cannot confirm or exclude this diagnosis — it needs blood cultures, and those need to be taken before antibiotics start. Booking a private echocardiogram in that situation introduces a delay of hours or days, and produces a result that cannot be acted on without the hospital work-up anyway. A normal scan could also give false reassurance to someone who needs admitting. The scan is not the bottleneck; getting into the right system is.
This reflects our standing operational policy rather than any individual case.
Treatment is delivered in hospital and takes weeks rather than days. It centres on a prolonged course of intravenous antibiotics — commonly between two and six weeks — chosen according to the organism grown from the blood cultures. Patients are monitored with repeat blood tests and repeat echocardiography to check the infection is clearing and the valve is holding up.
A proportion of patients need heart surgery, either to replace a valve that has been destroyed, to remove a large vegetation at high risk of breaking off, or to clear infection that will not respond to antibiotics alone. These decisions are made by a specialist endocarditis team including cardiologists, cardiac surgeons and infection specialists.
On prevention: UK guidance does not recommend routine antibiotics before dental work for most people. If you are in a higher-risk group, your cardiologist or dentist will advise you individually. Good dental hygiene and prompt treatment of dental infection matter more than one-off antibiotic doses.
We would advise against it, and we would decline the booking if the reason given was suspected endocarditis. The diagnosis requires blood cultures taken before antibiotics, alongside imaging, and it needs a hospital team. If this is a live concern, contact your GP urgently or attend A&E.
It is a serious condition that can damage heart valves permanently and cause complications in other organs. Outcomes are considerably better when it is diagnosed and treated early, which is precisely why delay matters.
No. A transthoracic scan can miss small vegetations, and it is less reliable where there is a replacement valve or a pacemaker lead. Where suspicion is high, a transoesophageal study or repeat imaging is usually needed.
Most people do not. UK guidance moved away from routine prophylaxis some years ago. If you have a replacement valve or have had endocarditis before, ask your cardiologist for individual advice rather than assuming either way.
Follow-up usually includes repeat echocardiography to check valve function and to establish a new baseline. That surveillance imaging is normally arranged by your cardiology team; if you are asked to arrange it privately, we are happy to help — but only as part of a plan your cardiologist has set.
CQC-registered clinic · HCPC-registered sonographers · BMUS member · ICO-registered. This page is information only — suspected infective endocarditis needs urgent NHS assessment, not a private appointment.
Cardiac imaging at our clinic: echocardiography for surveillance arranged by your cardiology team.
