E/e′ divides mitral inflow E by the early diastolic velocity of the mitral annulus. E rises with left atrial pressure, e′ reflects how fast the LV relaxes, and the ratio estimates LV filling pressure.
By James Napolitano. Cutoffs from the guidelines cited below.
Mitral E
In the apical 4-chamber view, place a 1 to 3 mm PW gate at the tips of the mitral leaflets when they are open. Measure the peak of the early wave (E), just after the T wave. At the annulus E reads low, and E/e′ comes out wrong.
Annular e′
Switch to tissue Doppler in the same view.
Place a 5 to 10 mm gate at the septal insertion of the mitral leaflets, then at the lateral insertion.
Keep the beam parallel to the annulus motion. Sweep 100 mm/s.
Each recording shows s′ above the baseline in systole, and e′ and a′ below it in diastole. Measure peak e′.
Live exampleFigure 1. Live apical 4-chamber view with a tissue Doppler gate. The gate moves from the blood pool to the septal annulus, up the septum, then to the lateral annulus. Tissue Doppler filters out blood, so the cavity records almost nothing. Drag the gate yourself.
Calculate
Average e′ = (septal e′ + lateral e′) / 2 Average E/e′ = E / average e′
Lateral e′ is normally higher than septal e′. Averaging the two is preferred. If only one site is available, use the site-specific cutoffs below.
Calculator
cm/s
cm/s
cm/s
Live exampleFigure 2. Live mitral inflow, septal and lateral tissue Doppler and TR velocity: the four inputs to the 2025 ASE algorithm.
Tap a trace to freeze and measure.
Stroke volume
Apical 5-chamber
Angle to flow --
What the gate records
Move the gate and watch the trace change.
Cutoffs (2025 ASE)
Variable
Abnormal
e′
Septal ≤6, lateral ≤7 or average ≤6.5 cm/s
Average E/e′
≥14
Single site E/e′
Septal ≥15 or lateral ≥13
E/e′ is one of three primary variables in the 2025 ASE diastolic algorithm, with e′ and peak TR velocity.1 See the step-by-step algorithm.
Pitfalls
Mitral annular calcification, mitral stenosis, mitral repair or replacement make e′ and E/e′ unreliable.
A regional wall motion abnormality at one site changes that site's e′. Use the average.
In constrictive pericarditis lateral e′ can be lower than septal e′, the reverse of normal.
Age-adjusted lower limits for e′ can be used instead of fixed cutoffs.1
Practice this on live Doppler.Critical Care Echo Trainer has all five measurements: stroke volume, RVSP, diastolic function, tamponade and TAPSE. Random cases with an answer key, and the full Acquire view with probe position and technique for each. $59, one-time.
Nagueh SF, et al. Recommendations for the evaluation of left ventricular diastolic function by echocardiography and for heart failure with preserved ejection fraction diagnosis: an update from the American Society of Echocardiography. J Am Soc Echocardiogr. 2025;38:537-569.