Diastology on echocardiography

 

Diastology on echocardiography refers to the assessment of left ventricular (LV) filling, relaxation, compliance, and filling pressures. It is a core component of modern echo practice because many patients with heart failure, hypertension, diabetes, ischemia, or valvular disease have preserved systolic function but significant diastolic dysfunction.

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Why Diastolic Assessment Matters

• Explains symptoms in patients with normal ejection fraction

• Essential for diagnosing HFpEF

• Reflects myocardial ischemia, fibrosis, and hypertrophy earlier than systolic indices

• Guides prognosis and management

Diastolic dysfunction often precedes systolic dysfunction.

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Physiology of Diastole (Echo Perspective)

Diastole has four functional phases:

1. Isovolumic relaxation

2. Early rapid filling

3. Diastasis

4. Atrial contraction

Echo parameters are designed to interrogate these phases.

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Core Echocardiographic Parameters in Diastology

1. Mitral Inflow Doppler

Measured using pulsed-wave Doppler at the mitral leaflet tips.

Key components: • E wave – early diastolic filling

• A wave – atrial contraction

• E/A ratio

• Deceleration time (DT)

• Isovolumic relaxation time (IVRT)

Interpretation: • Reduced E, E/A < 0.8 → impaired relaxation

• E/A 0.8–2 → indeterminate or pseudonormal

• E/A ≥ 2 → restrictive filling

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2. Tissue Doppler Imaging (TDI)

Sampled at septal and lateral mitral annulus.

Key parameter: • e′ velocity (septal and lateral)

Significance: • Reflects myocardial relaxation

• Less preload dependent than transmitral inflow

Normal values (approximate): • Septal e′ ≥ 7 cm/s

• Lateral e′ ≥ 10 cm/s

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3. E/e′ Ratio

Calculated using mitral E wave divided by average e′.

Clinical relevance: • Surrogate for LV filling pressures

Interpretation: • E/e′ < 8 → normal filling pressure

• E/e′ 9–14 → indeterminate

• E/e′ > 14 → elevated filling pressure

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4. Left Atrial Volume Index (LAVI)

Represents chronic exposure to elevated LV filling pressures.

Normal: • ≤ 34 ml/m²

Enlarged LA strongly supports chronic diastolic dysfunction.

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5. Pulmonary Vein Doppler

Provides complementary information on LA pressure and compliance.

Key waves: • S wave (systolic)

• D wave (diastolic)

• Ar wave (atrial reversal)

Findings: • Blunted S wave, prominent D wave → elevated LA pressure

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Grading of Diastolic Dysfunction (ASE-Based Approach)

Grade I – Impaired Relaxation

• E/A < 0.8

• Normal filling pressures

• Common in aging, mild LVH

Grade II – Pseudonormal

• E/A appears normal (0.8–2)

• Elevated filling pressures

• Requires TDI, E/e′, LAVI for diagnosis

Grade III – Restrictive Filling

• E/A ≥ 2

• Short DT

• Markedly elevated filling pressures

• Poor prognosis

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Diastology in Special Clinical Settings

Heart Failure with Preserved EF (HFpEF)

• Diastolic dysfunction is the hallmark

• Elevated E/e′, enlarged LA, high TR velocity support diagnosis

Hypertension and LVH

• Early impaired relaxation

• Progresses to pseudonormal filling

Ischemia

• Diastolic abnormalities appear before systolic changes

• Reduced e′ is an early marker

Atrial Fibrillation

• No A wave

• Reliance on E/e′, TR velocity, LA size

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Common Pitfalls in Diastolic Assessment

• Age-related changes mimicking pathology

• Load dependence of Doppler parameters

• Mitral valve disease affecting inflow patterns

• Poor alignment in TDI measurements

Always integrate multiple parameters rather than relying on a single index.

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Practical Echo Reporting Tips

• Mention diastolic grade explicitly

• Comment on LV filling pressures

• Correlate with symptoms and rhythm

• Avoid overcalling dysfunction in elderly asymptomatic patients

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Key Point:

Diastology is not a single measurement but a comprehensive integration of Doppler inflow, tissue velocities, atrial size, and clinical context. Mastery of diastolic echo transforms echocardiography from a structural test into a true hemodynamic assessment tool.