Diastolic dysfunction on echocardiography

Diastolic dysfunction on echocardiography: a comprehensive, guideline-oriented review

Diastolic dysfunction refers to impaired left ventricular (LV) filling due to abnormal relaxation, increased chamber stiffness, or both, leading to elevated LV filling pressures. It is a central mechanism in heart failure with preserved ejection fraction (HFpEF) and contributes significantly to symptoms, prognosis, and management decisions.

PHYSIOLOGY OF DIASTOLE

LV diastole has four phases:

1. Isovolumic relaxation (IVRT): energy-dependent myocardial relaxation after aortic valve closure

2. Early rapid filling: pressure gradient–driven filling (E wave)

3. Diastasis: minimal flow when LA and LV pressures equalize

4. Atrial contraction: late filling (A wave)

Diastolic dysfunction develops when relaxation is delayed, compliance is reduced, or left atrial (LA) pressure rises to compensate.

ECHOCARDIOGRAPHIC PARAMETERS FOR DIASTOLIC ASSESSMENT

1. Mitral inflow Doppler

Measured in apical 4-chamber view with pulsed-wave Doppler at mitral leaflet tips.

Key variables: • E wave: early diastolic filling velocity

• A wave: atrial contraction velocity

• E/A ratio

• Deceleration time (DT) of E wave

• Isovolumic relaxation time (IVRT)

Patterns: • Impaired relaxation: E/A < 1, prolonged DT, prolonged IVRT

• Pseudonormal: E/A appears normal due to raised LA pressure

• Restrictive filling: E/A ≥ 2, short DT, short IVRT

Limitations: • Highly preload dependent

• Pseudonormal pattern can mask true dysfunction

2. Tissue Doppler imaging (TDI)

Assesses myocardial relaxation directly. Sample at septal and lateral mitral annulus.

Key variables: • e′ (Ea): early diastolic annular velocity

• a′ (Aa): late diastolic annular velocity

• s′: systolic annular velocity

Interpretation: • Reduced e′ is the earliest marker of diastolic dysfunction

• Septal e′ < 7 cm/s or lateral e′ < 10 cm/s indicates abnormal relaxation

E/e′ ratio: • Surrogate of LV filling pressure

• Average E/e′ > 14 suggests elevated LV filling pressures

• Less reliable in significant MR, MAC, regional wall motion abnormalities

3. Pulmonary venous flow

Obtained with pulsed-wave Doppler in right upper pulmonary vein.

Components: • S wave: systolic forward flow

• D wave: diastolic forward flow

• Ar wave (PA): atrial reversal

Key findings: • Normal: S ≥ D

• Elevated LV filling pressure: D > S

• PA duration > mitral A duration (PA d > MA d) suggests raised LVEDP

Useful to unmask pseudonormal filling.

4. Left atrial size

Reflects chronic diastolic burden rather than acute filling pressures.

• LA volume index > 34 mL/m² indicates chronically elevated LV filling pressures

• Normal LA size does not exclude early diastolic dysfunction

5. Tricuspid regurgitation velocity

Used to estimate pulmonary artery systolic pressure.

• TR velocity > 2.8 m/s supports elevated LV filling pressures (if no primary pulmonary disease)

6. Color M-mode flow propagation velocity (Vp)

Measures speed of early diastolic inflow propagation.

• Vp < 45 cm/s suggests impaired relaxation

• E/Vp ratio > 2.5 correlates with elevated LV filling pressure

Less commonly used now but helpful in tachycardia or atrial fibrillation.

GRADING OF DIASTOLIC DYSFUNCTION (SIMPLIFIED)

Grade I – Impaired relaxation

• E/A < 1

• e′ reduced

• Normal or mildly elevated filling pressures

• Common in aging and early disease

Grade II – Pseudonormal filling

• E/A 1–1.5

• Reduced e′

• Elevated filling pressures

• Requires integration of E/e′, LA size, TR velocity, pulmonary venous flow

Grade III – Restrictive filling

• E/A ≥ 2

• Short DT (<150 ms)

• Markedly elevated filling pressures

• Poor prognosis

• May be reversible or fixed

DIAGNOSTIC ALGORITHM (CLINICALLY USED)

In patients with normal LVEF: Assess four variables:

1. Average E/e′

2. Septal or lateral e′ velocity

3. LA volume index

4. TR velocity

• ≥3 abnormal → diastolic dysfunction present

• 2 abnormal → indeterminate

• ≤1 abnormal → normal diastolic function

SPECIAL CLINICAL SITUATIONS

Atrial fibrillation: • No A wave

• Use average E/e′, TR velocity, LA size, DT

• Beat averaging mandatory

Mitral valve disease: • Mitral inflow unreliable

• Rely more on TDI, pulmonary venous flow, LA size

Hypertrophic cardiomyopathy: • Severe relaxation abnormality with small LV cavity

• Elevated filling pressures despite preserved EF

Restrictive cardiomyopathy / amyloidosis: • Restrictive filling pattern

• Severely reduced e′

• Disproportionately enlarged atria

CLINICAL IMPLICATIONS

• Explains dyspnea in patients with preserved EF

• Guides HFpEF diagnosis

• Predicts outcomes in hypertension, CAD, valvular disease

• Influences volume management and blood pressure control

• Advanced grades carry worse prognosis

KEY PITFALLS

• Single parameter interpretation is unreliable

• Always integrate clinical context and multiple echo indices

• Age significantly affects normal values

• Loading conditions alter Doppler patterns

SUMMARY

Diastolic dysfunction assessment on echocardiography requires an integrated, multiparametric approach. Tissue Doppler velocities, mitral inflow, LA size, TR velocity, and supportive indices together allow accurate grading and estimation of filling pressures. Mastery of these principles is essential for diagnosing HFpEF, evaluating unexplained dyspnea, and improving patient management.

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