EchoAssist™ Diastolic Function Navigator

LV Diastolic Assessment · LARS Included · ASE 2025

Follow this systematic sequence for every diastolic function assessment. Obtain all parameters before applying the ASE 2025 two-step grading algorithm.

1
Assess LV Systolic Function
Confirm LVEF. Diastolic grading applies to preserved (EF ≥ 50%) and mildly reduced (EF 40–49%) function. Separate algorithm applies for EF < 40%.
2
Tissue Doppler Imaging (TDI) — e' Velocity
Pulsed TDI at septal and lateral mitral annulus. e' is the starting point for diastolic assessment (ASE 2025 Step 1). Measure septal and lateral e'. Use age-specific cutoffs (Table 6). Average for E/e' ratio.
3
Mitral Inflow — E/e' Ratio
PW Doppler at mitral leaflet tips. Measure E wave, A wave, E/A ratio, and DT. Calculate average E/e' using TDI from Step 2. E/e' > 14 = elevated LAP (Step 2 criterion). Sweep speed 100 mm/s.
4
TR Velocity & PASP
CW Doppler across tricuspid valve. Peak TR velocity > 2.8 m/s = elevated RVSP (Step 2 criterion). RVSP = 4(TRV²) + estimated RAP. Use multiple windows to find highest velocity.
5
Pulmonary Venous Flow
PW Doppler in right upper pulmonary vein. Measure S, D, Ar velocity, and Ar duration. Ar – A duration > 30 ms = elevated LVEDP. S/D < 1 suggests elevated LA pressure.
6
LA Reservoir Strain (LARS)
Dedicated apical 4C and 2C views at 50–70 fps. R-R gating. LARS < 18% = elevated LVFPs (Step 2 criterion). Do not use in AF, significant MR, or heart transplant.
7
Left Atrial Volume Index (LAVI)
Biplane Simpson's method. Index to BSA. LAVI > 34 mL/m² = LA enlargement (Step 2 criterion). Exclude PVs and LAA from tracing.
8
IVRT (Isovolumic Relaxation Time)
PW Doppler between LVOT and mitral inflow, or tissue Doppler method. Normal IVRT: 70–90 ms. Shortened IVRT (< 60 ms) suggests elevated LAP. Prolonged IVRT (> 100 ms) suggests impaired relaxation.
9
Apply ASE 2025 Two-Step Algorithm
Step 1: Is e' reduced (impaired relaxation)? Step 2: Count elevated LAP markers (E/e' > 14, TR > 2.8 m/s, LARS < 18%, LAVi > 34). See Grading Algorithm section.

The ASE 2025 algorithm uses a two-step approach. Step 1 assesses LV relaxation via e' velocity. Step 2 counts markers of elevated LA pressure. Diastolic dysfunction is present when Step 1 is positive and ≥1 Step 2 marker is present, or when Step 1 is negative but ≥2 Step 2 markers are present.

Exclusions: Do not apply this algorithm to patients with atrial fibrillation, non-cardiac pulmonary hypertension, LVAD, or pericardial constriction.

Step 1 — Impaired LV Relaxation (e' Velocity)

Age 20–39

Septal: ≤ 7 cm/s

Lateral: ≤ 10 cm/s

Average: ≤ 9 cm/s

Age 40–65

Septal: ≤ 6 cm/s

Lateral: ≤ 8 cm/s

Average: ≤ 7 cm/s

Age > 65

Septal: ≤ 8 cm/s

Lateral: ≤ 7 cm/s

Average: ≤ 6.5 cm/s

Step 2 — Markers of Elevated LA Pressure

Average E/e'

Abnormal: > 14

Surrogate for LV filling pressure

LARS (LA Reservoir Strain)

Abnormal: < 18%

NEW in ASE 2025 — high specificity for elevated LVFPs

Valsalva E/A (E/AoB-A)

Abnormal: ≥ 32

Decrease in E/A ≥ 50% with Valsalva

LAVi

Abnormal: > 34 mL/m²

Marker of chronic LA pressure load

Grade	Step 1	Step 2 Criteria Met	E/A Pattern	LAP
Normal	Normal e'	< 2 of 4 abnormal	E/A 0.8–2.0, DT 160–240 ms	Normal
Grade I	Reduced e'	≤ 1 of 4 abnormal	E/A ≤ 0.8, DT > 200 ms	Normal
Grade II	Reduced e'	≥ 2 of 4 abnormal	E/A 0.8–2.0, DT 160–200 ms	Elevated
Grade III	Reduced e'	≥ 2 of 4 abnormal	E/A > 2.0, DT < 160 ms	Markedly elevated
Indeterminate	Variable	Exactly 2 of 4, mixed pattern	Variable	Cannot classify

EF < 40%: When LVEF is reduced, diastolic dysfunction is assumed to be present. The grading algorithm is used to estimate filling pressure severity rather than confirm dysfunction.

Echo Severity Calculators — run guideline-based grading and LAP estimation directly.

Diastology LAP Estimation