Multiparametric Assessment of Diastolic Dysfunction – Evidence from ASE/EACVI Guidelines

Limitations of E/A Ratio Alone

• The E/A ratio by itself cannot diagnose diastolic dysfunction; the 2016 ASE/EACVI guidelines mandate a multiparametric approach and prohibit reporting a diastolic grade when only a single parameter is available. 1

Threshold Values and Interpretation of E/A

• An E/A ≤ 0.8 together with a peak early‑mitral velocity ≤ 50 cm s⁻¹ suggests normal or low left‑atrial pressure and corresponds to Grade I diastolic dysfunction. 2
• An E/A ≥ 2 suggests elevated left‑atrial pressure and Grade III diastolic dysfunction, but values > 2 are physiologically normal in younger adults (approximately < 40 years). 3
• When the E/A ratio falls between 0.8 and 2, or when E/A ≤ 0.8 with peak early‑mitral velocity > 50 cm s⁻¹, additional echocardiographic parameters are required to determine filling pressures. 4

Required Additional Echocardiographic Parameters

• Average E/e′ ratio > 14 indicates elevated left‑ventricular filling pressures. 5
• Left‑atrial maximum volume index > 34 mL m⁻² indicates elevated filling pressures. 2
• Tricuspid‑regurgitation jet peak velocity > 2.8 m s⁻¹ indicates elevated filling pressures. 2

Diagnostic Algorithm and Criteria

• For Grade II diastolic dysfunction, at least two of the three parameters (E/e′, LA volume index, TR velocity) must meet their respective cut‑off values. 6
• In patients with preserved ejection fraction, the 2016 ASE/EACVI algorithm requires assessment of four parameters: septal e′ < 7 cm s⁻¹, lateral e′ < 10 cm s⁻¹, average E/e′ > 14, LA volume index > 34 mL m⁻², and TR velocity > 2.8 m s⁻¹. Diastolic dysfunction is diagnosed when more than half of the available parameters exceed the cut‑offs. 7

Age and Clinical Context Influences

• A fixed E/A threshold of < 1.0 provides only ~46 % specificity for detecting age‑independent diastolic abnormalities, reflecting the strong age dependence of the E/A ratio. 8
• After cardioversion, left‑atrial stunning can markedly reduce A‑wave velocity, falsely elevating the E/A ratio despite normal filling pressures. 3
• In young adults, an E/A > 2 may be a normal physiological finding and should not be interpreted as pathological. 4
• “Pseudonormalization” can occur where the E/A ratio appears normal (0.8–2) even though left‑atrial pressure is significantly elevated. 8

Structural Cardiac Findings Supporting Diastolic Dysfunction

• Left‑atrial enlargement that exceeds right‑atrial size strongly suggests chronically elevated filling pressures. 6
• Pathologic left‑ventricular hypertrophy is consistent with diastolic dysfunction. 6
• Assessment of regional wall‑motion abnormalities is recommended as part of the comprehensive diastolic evaluation. 6

Reporting Indeterminate Findings

• When only a single parameter is obtainable or when ≥ 50 % of the assessed parameters are discordant, the guidelines advise labeling the result “indeterminate” and refraining from assigning a diastolic dysfunction grade. 5

E/A Ratio Assessment in Diastolic Function

Measurement Technique

• Position the pulsed‑wave Doppler sample volume at the tips of the mitral valve leaflets during diastole to record transmitral flow velocities. 9
• Record the peak velocity of the early‑diastolic (E) wave and the peak velocity of the atrial‑contraction (A) wave, then calculate the E/A ratio by dividing the E‑wave velocity by the A‑wave velocity. 9

Interpretation of Isolated E/A Values

Low E/A (≤ 0.8) with Low Peak E (≤ 50 cm/s)

• Indicates normal or low left‑atrial pressure and corresponds to Grade I diastolic dysfunction (impaired relaxation). No additional parameters are required for this classification. [9][10]

High E/A (≥ 2)

• Reflects elevated left‑atrial pressure and defines Grade III diastolic dysfunction (restrictive filling pattern).
• In patients with heart failure with reduced ejection fraction, the deceleration time of the E‑wave is typically < 160 ms. [9][10]

Indeterminate E/A Zone (0.8 – 2.0 or ≤ 0.8 with Peak E > 50 cm/s)

• Requires evaluation of three supplemental parameters:

• Grade II diastolic dysfunction is diagnosed when ≥ 2 of the 3 supplemental parameters meet their cut‑off values. [9][10]

• Grade I diastolic dysfunction is diagnosed when only 1 of the 3 supplemental parameters meets its cut‑off value. [9][10]

• Findings are labeled “indeterminate” when there is only 50 % concordance among parameters or when fewer than two supplemental measurements are available. 9

Pseudonormalization

• A normal‑appearing E/A ratio (0.8 – 2.0) can mask significantly elevated left‑atrial pressure; therefore, additional parameters must always be assessed to exclude pseudonormalization. 9

Special Scenarios

First‑Degree AV Block or Bundle‑Branch Block

• When the PR interval exceeds 280 ms or a bundle‑branch block is present, the E and A waves may fuse, rendering the E/A ratio unreliable. In such cases, the ratio should not be interpreted, and alternative diastolic indices should be used. 11

Atrial Fibrillation

• The E/A ratio cannot be measured because organized atrial contraction is absent. Assessment should instead rely on E‑wave velocity, deceleration time, E/e′ ratio, and left‑atrial size. 12

Structural Correlates Supporting Elevated Filling Pressures

• Pathologic left‑ventricular hypertrophy (gender‑specific LV mass above normal limits) is consistent with diastolic dysfunction. 9
• Elevated pulmonary‑artery systolic pressure estimated from the tricuspid‑regurgitation jet strongly suggests increased left‑ventricular filling pressure, provided primary pulmonary disease is excluded. 9