Suspected infective endocarditis (adult)
Fever or bacteraemia with a predisposing heart condition, new murmur, emboli or immune signs.
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Infective Endocarditis Diagnosis (Duke-ISCVID 2023)
Infective Endocarditis Diagnosis (Duke-ISCVID 2023): Suspected infective endocarditis (adult) → Blood cultures before antibiotics. No thrombolysis if IE...
Pathway Overview
13 steps
Algorithm Steps
13 total
01Start 02Warning Blood cultures before antibiotics. No thrombolysis if IE stroke
Take cultures first, then start empirical IV antibiotics promptly (regimen: eTG Antibiotic or local ID advice).
- Take at least 3 blood culture sets (1 aerobic + 1 anaerobic bottle each, each bottle filled to its marked adult volume) before antibiotics, from peripheral veins, separate venepunctures if possible
- Septic shock or unstable: draw the sets quickly (no need to wait between sets), then start empirical IV antibiotics at once
- Embolic stroke with suspected IE: do not give thrombolysis; brain CT or MRI and urgent stroke team advice
03Action Echocardiography: TTE first, then TOE
Prosthetic valve or intracardiac device: a normal TTE does not exclude IE; do TOE.
- TTE first in all patients
- TOE if TTE is negative or non-diagnostic and suspicion remains
- TOE if prosthetic valve or intracardiac device
- TOE even if TTE is positive, except isolated right-sided native valve IE with a good-quality TTE
- First study negative and suspicion still high: repeat TTE or TOE within 5-7 days
- Echo inconclusive: cardiac CT; prosthetic valve: also [18F]FDG PET/CT
04Action Major criteria (Duke-ISCVID 2023)
Antibiotics given before cultures can make cultures negative: send Coxiella and Bartonella serology and blood PCR.
- Blood cultures: typical organism in 2 or more separate sets, or non-typical organism in 3 or more sets (1 set = 1 aerobic + 1 anaerobic bottle)
- Typical: S. aureus, S. lugdunensis, E. faecalis, streptococci (except S. pneumoniae and S. pyogenes), Granulicatella, Abiotrophia, Gemella, HACEK
- With intracardiac prosthetic material, also typical: coagulase-negative staphylococci, C. striatum, C. jeikeium, S. marcescens, P. aeruginosa, C. acnes, nontuberculous mycobacteria, Candida
- Coxiella burnetii (Q fever): blood PCR, phase I IgG titre >1:800, or 1 positive blood culture
- Bartonella: blood PCR, or IgG titre 1:800 or more by IFA. Tropheryma whipplei: blood PCR
- Echo or cardiac CT: vegetation, leaflet perforation, leaflet aneurysm, abscess, pseudoaneurysm or intracardiac fistula
- Echo: significant new valve regurgitation compared with previous imaging (worse known regurgitation is not enough), or new partial prosthetic valve dehiscence
- [18F]FDG PET/CT: abnormal uptake at a native or prosthetic valve, aortic graft with valve involvement, device leads or other prosthetic material (prosthetic valve: at least 3 months after implant)
- Surgery: IE seen at direct inspection during heart surgery
05Action Minor criteria (Duke-ISCVID 2023)
Count each category once.
- Predisposition: prior IE, prosthetic valve, prior valve repair, congenital heart disease, more than mild regurgitation or stenosis, intracardiac device, HOCM, injection drug use
- Fever: temperature above 38.0 °C
- Vascular: arterial emboli, septic pulmonary infarcts, cerebral or splenic abscess, mycotic aneurysm, intracranial haemorrhage, conjunctival haemorrhages, Janeway lesions, purulent purpura
- Immunologic: positive rheumatoid factor, Osler nodes, Roth spots, immune-complex glomerulonephritis
- Microbiology short of major: positive blood culture not meeting the major rule; organism consistent with IE from another sterile site; single skin organism by PCR on a valve or wire
- Imaging: abnormal [18F]FDG PET/CT within 3 months of implant of a prosthetic valve, aortic graft, device leads or other prosthetic material
- Examination: new regurgitant murmur, only if echo is not available
06Decision Classify with Duke-ISCVID 2023
Definite, possible or rejected IE.
- Definite
07Action Definite IE: 2 major, 1 major + 3 minor, or 5 minor
Or pathology: organism (with clinical signs of active IE), or active IE on histology, in a vegetation, cardiac tissue, explanted valve or sewing ring, aortic graft with valve involvement, intracardiac device or arterial embolus.
08Warning Definite IE: call cardiac surgery now if these apply
Decide timing with the endocarditis team.
- Emergency (within 24 h): aortic or mitral IE with severe acute regurgitation, obstruction or fistula causing refractory pulmonary oedema or cardiogenic shock
- Urgent (within 3-5 days): severe acute regurgitation or obstruction with heart failure; abscess, pseudoaneurysm, fistula, enlarging vegetation, prosthetic dehiscence or new AV block; aortic or mitral IE with vegetation 10 mm or more after 1 or more embolic events despite antibiotics
- Also discuss surgery: fungi or multiresistant organisms; blood cultures positive for more than 1 week or persistent sepsis despite appropriate antibiotics; prosthetic valve IE due to S. aureus or non-HACEK Gram-negative bacteria; early prosthetic valve IE (within 6 months of valve surgery)
09Warning Definite IE: check stroke, bleeding, anticoagulants and device leads
These change the plan before antibiotics and surgery are set.
- Stroke or TIA: brain CT or MRI; no thrombolysis. If no intracranial haemorrhage and no coma, do not delay indicated heart surgery; plan with neurology
- On anticoagulant or antiplatelet: stop if major bleeding, including intracranial haemorrhage. Mechanical valve with intracranial haemorrhage: restart unfractionated heparin as soon as the team agrees
- Pacemaker or ICD (CIED) lead IE: complete device and lead extraction without delay
10Action Definite IE: endocarditis team care
Adults. Children: involve paediatric cardiology and infectious diseases. Pregnancy: add obstetrics and neonatology; do not delay indicated surgery.
- Endocarditis team: cardiology, infectious diseases, microbiology, cardiac surgery
- IV antibiotics by organism and valve type: see eTG Antibiotic (Australia) or ESC 2023 Section 7
- Repeat TTE or TOE at once if new murmur, embolism, persistent fever or bacteraemia, heart failure, abscess or AV block
- Injection drug use: offer addiction treatment
11Outcome Follow-up after treatment
TTE or TOE at the end of antibiotics. Teach recurrence risk and prevention, with emphasis on dental health.
- Possible
12Action Possible IE: 1 major + 1 minor, or 3 minor
Do more tests, then classify again. High suspicion: continue empirical antibiotics while testing, with infectious diseases advice.
- Repeat TTE or TOE within 5-7 days
- Native valve: cardiac CT
- Prosthetic valve: cardiac CT and [18F]FDG PET/CT
- Cultures negative: Coxiella and Bartonella serology, blood PCR; ask microbiology
- Symptoms of emboli: brain and whole-body imaging (CT, MRI or PET/CT)
- Path rejoins step 06Shared downstream outcome
- Rejected
13Outcome Rejected IE
Firm alternative diagnosis; or no recurrence after less than 4 days of antibiotics; or no IE at surgery or autopsy after less than 4 days of antibiotics; or criteria for possible IE not met. Suspicion still high: repeat echo within 5-7 days.
Guideline Source
The 2023 Duke-ISCVID Criteria for Infective Endocarditis: Updating the Modified Duke Criteria (Fowler VG et al., Clin Infect Dis 2023)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Diagnostic criteria only: antibiotic choice and doses are not given; use eTG Antibiotic (Australia) or the ESC 2023 guideline.
- Criteria support but do not replace clinical judgement; possible or rejected IE with high suspicion needs repeat imaging and specialist review.
- Surgery indications are a summary; decide type and timing with the endocarditis team.
- Adult pathway. Duke-ISCVID criteria also apply to children, but work-up and management need paediatric cardiology and infectious diseases.
Contraindicated Populations
pediatric
Applicable Regions
AUUSEU
AU: Antibiotic choice and doses: Therapeutic Guidelines (eTG Antibiotic). Q fever (Coxiella burnetii) is endemic; send serology in culture-negative IE. Rheumatic heart disease is common in Aboriginal and Torres Strait Islander people and counts as a predisposition.
EU: ESC 2023 uses its own modified Duke criteria; they are close to, but not the same as, Duke-ISCVID 2023.
US: Duke-ISCVID 2023 criteria (ISCVID); AHA 2015 statement for treatment.
Version 2Next review: 2027-09-30
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Related Resources
Frequently Asked Questions
What is the Infective Endocarditis Diagnosis (Duke-ISCVID 2023)?
The Infective Endocarditis Diagnosis (Duke-ISCVID 2023) is a diagnostic clinical algorithm for Cardiology. It provides a structured decision tree to guide clinical decision-making, based on The 2023 Duke-ISCVID Criteria for Infective Endocarditis: Updating the Modified Duke Criteria (Fowler VG et al., Clin Infect Dis 2023).
What guideline is the Infective Endocarditis Diagnosis (Duke-ISCVID 2023) based on?
This algorithm is based on The 2023 Duke-ISCVID Criteria for Infective Endocarditis: Updating the Modified Duke Criteria (Fowler VG et al., Clin Infect Dis 2023) (DOI: 10.1093/cid/ciad271).
What are the limitations of the Infective Endocarditis Diagnosis (Duke-ISCVID 2023)?
Known limitations include: Diagnostic criteria only: antibiotic choice and doses are not given; use eTG Antibiotic (Australia) or the ESC 2023 guideline.; Criteria support but do not replace clinical judgement; possible or rejected IE with high suspicion needs repeat imaging and specialist review.; Surgery indications are a summary; decide type and timing with the endocarditis team.; Adult pathway. Duke-ISCVID criteria also apply to children, but work-up and management need paediatric cardiology and infectious diseases.. Individual patient factors may require deviation from these recommendations.
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