Left Ventricular Diastolic Function: Evaluation and Grading

Left ventricular diastolic function refers to the heart’s ability to relax and fill during diastole. Diastolic dysfunction underlies heart failure with preserved ejection fraction (HFpEF) and contributes to symptoms across many other cardiac conditions, which is why assessing it carefully — not just noting “diastolic function appears normal/abnormal” — matters clinically. This tutorial covers the individual Doppler and tissue Doppler parameters involved, and, importantly, the current guideline-based framework for combining them, which differs in a few specific, clinically meaningful ways from the E/A-based staging still seen in a lot of teaching material.

The Current Framework: Two Algorithms, Not One

The 2016 ASE/EACVI diastolic function guideline is explicit that the correct approach depends on whether the patient has a normal or depressed ejection fraction — these are genuinely different algorithms, not two ways of describing the same thing.

Algorithm A: Normal EF, No Apparent Myocardial Disease

For patients with normal LVEF and no known myocardial disease (or when myocardial disease can’t be determined), the guideline recommends a four-parameter screening approach, checking whether each of the following is abnormal:

1. Average E/e′ ratio > 14
2. Septal e′ velocity < 7 cm/s, or lateral e′ velocity < 10 cm/s
3. Peak TR velocity > 2.8 m/s
4. LA (maximum) volume index > 34 mL/m²

Number of abnormal parameters	Interpretation
0 or 1	Normal diastolic function
2	Indeterminate
3 or 4	Diastolic dysfunction

This is a genuinely different way of thinking about diastolic assessment than “look at the E/A ratio” — it’s a structured count of how many independent signals point toward dysfunction, which is part of why it has better reproducibility across readers than relying on a single ratio.

Algorithm B: Depressed EF, or Myocardial Disease With Normal EF

For patients in sinus rhythm with depressed LVEF, or with known myocardial disease despite a normal LVEF, a different algorithm both grades diastolic dysfunction and estimates filling pressure, starting from the mitral E/A ratio and peak E velocity:

• Grade I (impaired relaxation, normal filling pressures): E/A ratio ≤ 0.8 and E velocity ≤ 50 cm/s
• Grade III (restrictive, markedly elevated filling pressures): E/A ratio ≥ 2
• Grade II: everything in between (E/A ratio > 0.8 but < 2, or E/A ≤ 0.8 with E > 50 cm/s) — assigning Grade II specifically requires confirming with the same three supporting parameters used in Algorithm A (average E/e′ > 14, LA volume index > 34 mL/m², peak TR velocity > 2.8 m/s), with the majority of available parameters abnormal

These cutoffs are worth knowing precisely, since rounder numbers (E/A < 1.0, 1.0–1.5, and > 1.5) are still common in older teaching material and even some conceptual overviews. The current guideline’s actual thresholds are E/A ≤ 0.8 and E/A ≥ 2 for Grades I and III respectively — noticeably different from the older rounded cutoffs, and worth using the precise numbers when accuracy matters.

Important: Neither Algorithm Applies Universally

The 2016 guideline explicitly states that Algorithm B does not apply to patients with hypertrophic cardiomyopathy, mitral stenosis or significant mitral regurgitation, severe aortic regurgitation, moderate or severe mitral annular calcification, atrial fibrillation, left bundle branch block or a paced ventricular rhythm, group I or groups III–V pulmonary hypertension, advanced heart block, heart transplant recipients, or patients with an LV assist device. In these populations, diastolic assessment requires a more individualized approach drawing on the parameters below, rather than a formulaic application of the algorithm.

Key Individual Parameters

PW Doppler Mitral Inflow

With the sample volume at the mitral leaflet tips in the apical four-chamber view:

• E wave — early diastolic inflow velocity, reflecting the pressure gradient between LA and LV during early, passive filling
• A wave — late diastolic inflow velocity during atrial contraction
• E/A ratio — roughly 1.1–1.5 is a reasonable resting reference range in a normal heart, though as above, the guideline algorithms don’t use a single “normal E/A” cutoff in isolation the way this range might suggest — E/A is one input among several, not a standalone verdict
• Deceleration time (DT) — the time for the E wave to decelerate; roughly 160–240 ms is a typical reference range. A prolonged DT suggests impaired relaxation; a shortened DT suggests restrictive filling.
• Isovolumic relaxation time (IVRT) — the interval between aortic valve closure and mitral valve opening; roughly 60–100 ms depending on age (shorter in younger patients), prolonged with impaired relaxation and shortened with restrictive filling. In patients with depressed EF specifically, an IVRT of 65 ms or less is one of several supplementary markers of elevated filling pressure.

Pulmonary Vein Doppler

With the PW Doppler sample volume placed roughly 1 cm into a pulmonary vein from the LA:

• S wave — systolic forward flow
• D wave — diastolic forward flow
• AR wave (atrial reversal) — retrograde flow into the pulmonary veins during atrial contraction; an AR velocity greater than roughly 25 cm/s is a commonly cited marker that becomes more prominent with reduced LV compliance and elevated filling pressure

Left Atrial Volume

LA size reflects the chronic, cumulative burden of elevated filling pressure — unlike Doppler velocities, which capture an instant in the cardiac cycle, LA volume is more of a “memory” of sustained pressure elevation over time. An LA maximum volume index greater than 34 mL/m² is the specific threshold used in both current algorithms above. See the Evaluation of the Left Atrium tutorial for LA sizing methods, normal values, and how LA strain and function fit into the broader picture.

Flow Propagation Velocity (Vp)

Measured with color M-mode: align the cursor through the mitral valve into the LV cavity in the apical four-chamber view, and measure the slope of the leading edge of the first aliasing (E-wave) signal from the mitral leaflets to roughly 4 cm into the LV cavity. A Vp greater than roughly 50 cm/s is generally considered normal; a reduced Vp suggests impaired relaxation. This is a less commonly reported parameter than the others on this page, useful mainly as a supplementary marker rather than a first-line measurement.

Tissue Doppler Imaging (TDI)

With the sample volume at the septal and lateral mitral annulus in the apical four-chamber view:

• e′ velocity (early diastolic annular velocity) — reflects the rate of myocardial relaxation directly, largely independent of preload, which is part of why it’s so useful combined with the (preload-dependent) E wave. The current guideline’s abnormal cutoffs are septal e′ < 7 cm/s and lateral e′ < 10 cm/s — note that the lateral cutoff is 10 cm/s, not 8 cm/s as sometimes stated; the two annular sites have different normal ranges and shouldn’t be treated interchangeably.
• a′ velocity (late diastolic annular velocity) — reflects the annular contribution from atrial contraction; reduced with atrial dysfunction or more advanced diastolic dysfunction.
• E/e′ ratio — the ratio of transmitral E velocity to annular e′ velocity, used to estimate LV filling pressure. The current guideline’s algorithm threshold is an average E/e′ > 14; some other sources cite a slightly higher cutoff (around 15) as more specific for elevated filling pressure, with a wider intermediate zone below that considered less conclusive on its own — treat the exact number as somewhat source-dependent, and always interpret E/e′ alongside the other three algorithm parameters rather than in isolation.

The Classic Pattern: Impaired Relaxation → Pseudonormalization → Restrictive Filling

Even though formal grading now runs through the algorithms above, the classic progression of diastolic dysfunction remains genuinely useful for understanding why the numbers change the way they do:

Impaired relaxation (early, mild dysfunction) — the ventricle relaxes more slowly than normal. Early diastolic filling is reduced and delayed, so more filling shifts to atrial contraction: E/A falls, DT and IVRT lengthen. Filling pressures are still normal at this stage, and patients are typically asymptomatic at rest.

Pseudonormalization — as relaxation worsens and LV compliance falls, left atrial pressure rises to compensate, pushing more blood across the mitral valve early in diastole despite the underlying relaxation abnormality. This can make the E/A ratio, DT, and IVRT drift back toward a deceptively “normal”-looking pattern — hence pseudonormalization — even though the underlying dysfunction, and the filling pressure elevation driving it, has actually worsened. This is exactly the scenario where e′ velocity (which stays reduced, since it reflects relaxation rather than pressure) and E/e′ (which rises, since E is pressure-boosted while e′ isn’t) are indispensable for seeing through the mitral inflow pattern alone.

Restrictive filling — with severely reduced LV compliance and markedly elevated filling pressure, early diastolic filling becomes rapid but is cut short abruptly as ventricular pressure rises sharply: E/A rises well above normal, DT and IVRT shorten markedly, and the left atrium — now chronically volume- and pressure-loaded — is typically enlarged and often hypocontractile, unable to contribute effectively to filling even when it contracts.

Clinical Applications

• Heart failure — distinguishing HFpEF from HFrEF, and identifying elevated filling pressure in patients with preserved EF and exertional symptoms. When resting filling pressure is normal but symptoms suggest otherwise, diastolic stress testing — repeating E/e′ and TR velocity with exercise — can unmask an abnormal filling pressure response (average E/e′ > 14 with exercise, alongside a TR velocity > 2.8 m/s) not apparent at rest.
• Hypertensive heart disease — diastolic dysfunction from chronically increased afterload is often an early finding, sometimes preceding any drop in EF.
• Atrial fibrillation — diastolic assessment is more complex here (and, as above, outside where Algorithm B formally applies); beat-to-beat variability in mitral inflow parameters can itself be informative, since a fixed, low-variability E velocity across varying RR intervals suggests elevated LA pressure.
• Valvular heart disease — significant mitral or aortic valve disease affects LV filling independent of intrinsic diastolic function, which is part of why these conditions are excluded from the standard algorithms above; assessment has to account for the valve lesion itself, not just the usual Doppler parameters.
• Cardiomyopathies — hypertrophic cardiomyopathy typically shows impaired relaxation with a normal or increased EF; restrictive cardiomyopathy typically shows a restrictive filling pattern with preserved or only mildly reduced EF — a reminder that the filling pattern and the EF don’t always move together. See Introduction to Diseases of the Myocardium for how restrictive physiology relates to, and sometimes evolves from, the other cardiomyopathy phenotypes. E/e′ itself has a genuine exception worth knowing: in constrictive pericarditis, medial e′ is preserved or even increases as disease severity worsens, so E/e′ stays normal or low despite elevated filling pressure — the opposite of its usual behavior.

Advanced Techniques

Speckle-tracking strain during diastole is an active, less standardized area than systolic strain (GLS) — it can help detect early diastolic dysfunction, but reference ranges and clinical protocols are less firmly established than for the parameters above. 3D echocardiography provides more accurate LA volume measurement than 2D biplane methods, which matters directly here given how central LA volume index is to both current algorithms.