Mitral Inflow E/A Ratio by PW Doppler

Mitral Inflow E/A Ratio by Pulsed Wave Doppler

A Practical, Guideline-Based Approach

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1. Introduction

Mitral inflow assessment using pulsed wave (PW) Doppler is a fundamental component of diastolic function evaluation. The E/A ratio reflects the relationship between early passive LV filling (E wave) and late filling due to atrial contraction (A wave).

It is simple to measure but frequently misinterpreted if age, heart rate, and complementary parameters are not considered.

Guidelines reference: ASE/EACVI Recommendations for the Evaluation of LV Diastolic Function (2016 update).

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2. Physiology Behind E and A Waves

During diastole:

• Early rapid filling → E wave

• Diastasis → minimal flow

• Atrial contraction → A wave

Normal physiology:

Young adults: E > A (E/A > 1)

With aging: relaxation slows → E decreases, A increases

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3. Correct Method of Measuring E/A Ratio

A. Image Acquisition

View: Apical 4-chamber

Doppler type: Pulsed Wave (PW)

Sample volume size: 1–3 mm

B. Correct Sample Volume Placement

Place the sample volume:

At the tips of the mitral valve leaflets

In diastole

Not too atrial

Not too ventricular

Incorrect placement results in:

Overestimation (too ventricular)

Underestimation (too atrial)

C. Doppler Settings

Align Doppler beam parallel to flow

Sweep speed: 50–100 mm/s

Optimize gain (clear envelope, no noise)

Measure peak velocities

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4. How to Measure

1. Measure peak E velocity (m/s)

2. Measure peak A velocity (m/s)

3. Calculate:

E/A ratio = Peak E velocity / Peak A velocity

Always average over 3 beats (5 in atrial fibrillation not applicable as A absent).

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5. Normal Values

Adults <60 years:

E/A: 1.0 – 2.0

Older adults:

May be <1 due to normal aging

E velocity:

Usually 0.6–1.3 m/s

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6. Interpretation of E/A Ratio

E/A ratio alone is NOT sufficient. Always integrate with:

• Tissue Doppler e’

• E/e’ ratio

• LA volume index

• TR velocity

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Grade I – Impaired Relaxation

E/A < 0.8

E velocity < 50 cm/s

Normal or low filling pressures

Common in:

Aging

Hypertension

LV hypertrophy

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Grade II – Pseudonormal

E/A 0.8–2

Appears normal

Elevated filling pressures

Clues:

Reduced e’

Elevated E/e’

Enlarged LA

Requires Valsalva maneuver to unmask reversal.

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Grade III – Restrictive Filling

E/A ≥ 2

Short deceleration time

High filling pressures

Seen in:

Advanced cardiomyopathy

Restrictive physiology

Acute decompensated HF

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7. Important Pitfalls

• Tachycardia → E and A fusion

• Atrial fibrillation → no A wave

• Mitral stenosis → unreliable

• Significant MR → may elevate E

• High-output states → misleading patterns

Never interpret E/A in isolation.

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8. Practical Clinical Algorithm (Simplified)

Step 1: Measure E/A

Step 2: If E/A <0.8 and E <50 cm/s → Grade I

Step 3: If E/A >2 → Grade III

Step 4: If between 0.8–2 → assess 3 parameters:

Average E/e’ >14

TR velocity >2.8 m/s

LA volume index >34 ml/m²

≥2 positive → elevated filling pressures

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9. Key Take-Home Messages

• Proper sample placement is critical

• Age significantly influences E/A

• Pseudonormal pattern is common

• Always combine with tissue Doppler

• Follow ASE 2016 algorithm for accuracy