E/e′ ratio

E/e′ · Mitral E (PW at leaflet tips) divided by tissue Doppler e′ from the same study; report the average

Normal range & thresholds

Pathophysiology

Raised by

• Elevated left atrial pressure from any cause — HFpEF, HFrEF, hypertensive heart disease, ischaemia, restrictive and infiltrative disease, HCM
• Volume overload and renal failure
• Mitral stenosis (E is stenotic, not filling-driven — the ratio is not interpretable)
• Falsely raised: mitral annular calcification, mitral annuloplasty ring or prosthesis, prior mitral surgery, and regional infarction at the sampled annulus — all lower e′ mechanically

Lowered by

• Normal filling pressures
• Young age and athletic conditioning (high e′)
• Constrictive pericarditis — the preserved medial e′ produces a low E/e′ despite grossly elevated filling pressures: the classic false negative^[57]
• Primary mitral regurgitation with a normal ejection fraction — the guideline states plainly that E/e′ is not useful; use IVRT, Ar−A duration and IVRT/T_E-e′ instead^[2]
• Over-diuresis

Technique & pitfalls

• Measure E and e′ on the same study, at the same heart rate; the ratio of numbers from different visits is meaningless.
• Use the average of septal and lateral where both are valid; use lateral alone in LBBB, RV pacing, post-cardiac surgery and pulmonary hypertension; use septal alone with caution in lateral wall infarction.^[2]
• In pulmonary hypertension the guideline specifies the lateral ratio, with 8–13 recognised as weakly associated with LAP.^[2]
• Do not compute E/e′ at all in mitral stenosis, in a mechanical mitral prosthesis, or in significant mitral annular calcification — report why instead.
• State in the report which sites were used and which algorithm was applied.

Pseudo-change & artefact

• Anything that tethers the annulus falsely raises the ratio — annular calcification, rings, prostheses, prior surgery. This is the commonest false-positive diastolic report in clinical practice.
• Constriction and primary MR with normal EF falsely lower it.
• Diuresis: the ratio falls within hours — a ‘normal’ E/e′ after treatment does not mean the diastolic disease has gone.
• Tachycardia with E–A fusion; ectopy; atrial fibrillation cycle-length variation.
• Angle error in e′; sample volume off the annulus.
• Using a single site in a ventricle with regional disease.

Treatment thresholds

• HFpEF diagnosis: E/e′ ≥15 is a major functional criterion in HFA-PEFF, and the 2025 ASE guideline devotes a dedicated section to HFpEF diagnosis; a confirmed diagnosis brings SGLT2 inhibitors (class I in the 2023 ESC focused update) into play.^{[2,12,82,101]}
• Diastolic stress echocardiography: exercise average E/e′ ≥15 with peak TR velocity >2.8–3.4 m/s confirms exercise-induced elevation of filling pressure and converts unexplained dyspnoea into a diagnosis of HFpEF.^[105,106]
• Decongestion: a persistently elevated E/e′ at discharge predicts readmission and is used as an objective target for diuretic titration — the closest thing to a therapeutic threshold this parameter has.
• Hypertrophic cardiomyopathy: average E/e′ >14, with Ar−A ≥30 ms, TR velocity >2.8 m/s and LAVI >34 mL/m², indicates elevated filling pressures and supports symptom-directed therapy.^[2,13]
• Heart transplant: average E/e′ <7 normal, 7–14 needs E/SR_IVR, >14 elevated — a transplant-specific algorithm.^[2]

Next step

• Next: apply the full two-step algorithm; do not report a filling pressure on E/e′ alone.
• Then: if the primaries are discordant, measure LA reservoir strain, pulmonary vein S/D and LAVI.^[2]
• Then: if resting values are normal or grey-zone and the patient is breathless, do a diastolic stress echo; add natriuretic peptides and the H₂FPEF score.^{[102,105,106]}
• Then: when management genuinely hinges on the answer — unexplained dyspnoea, discordant non-invasive results, pre-transplant or pre-device evaluation — proceed to invasive haemodynamics with exercise. It remains the reference standard, and the guideline says so.^[2]

Drugs

• Loop diuretics — the fastest and largest reduction; hours to days.
• SGLT2 inhibitors reduce E/e′ and improve symptoms in HFpEF and HFrEF.^[82]
• ARNI lowers filling pressures and E/e′ alongside reverse remodelling.^[68]
• MRAs, nitrates and other preload reducers lower it acutely.
• Beta-blockers and rate control lengthen diastole, lower E and improve the ratio in tachycardia and in HCM; mavacamten improves it in obstructive HCM.^[72]
• Raised by: intravenous fluids, transfusion, NSAIDs, high-dose steroids, and any agent causing sodium retention.

Reversibility