What is Ee' (early diastolic mitral annular velocity) in an echocardiogram and how is it interpreted?

Understanding E/e' in Echocardiography

E/e' is the ratio of early diastolic transmitral flow velocity (E) to early diastolic mitral annular velocity (e'), which is primarily used to estimate left ventricular filling pressures with values >15 indicating elevated filling pressures. 1

Definition and Physiological Basis

• E represents the early diastolic transmitral flow velocity measured by conventional Doppler echocardiography, reflecting the pressure gradient between the left atrium and left ventricle during early diastole 2
• e' is the peak velocity of mitral annular motion during early diastole measured by tissue Doppler imaging (TDI), reported in cm/s 1
• e' can be measured at both septal and lateral mitral annulus sites, with proper sample volume positioning being critical for accurate measurement 2
• e' primarily reflects left ventricular relaxation with minimal influence from loading conditions when relaxation is impaired 2, 3

Measurement and Interpretation

• E/e' ratio is used to estimate left ventricular filling pressures 1, 2
• Normal E/e' is <15 (any measurement), while elevated E/e' is >15 (any measurement) 1
• Values for average E/e' ratio <8 usually indicate normal LV filling pressures 2
• Different cutoff values apply depending on the sampling site (septal vs. lateral) 2
• Septal e' velocity (IS-e') has been shown to better reflect LV longitudinal myocardial relaxation than lateral e' velocity (LW-e') 3

Clinical Applications

• E/e' is a key parameter in the assessment of left ventricular diastolic function 1
• It helps classify the grade of diastolic dysfunction:
  • Grade I (impaired relaxation): E/A ratio ≤0.8 with peak E velocity ≤50 cm/sec, normal E/e' 2
  • Grade II (pseudonormal filling): Intermediate values requiring additional parameters 2
  • Grade III (restrictive filling): E/A ratio ≥2, elevated E/e' 2
• E/e' contributes to the assessment of heart failure with preserved ejection fraction (HFpEF) 1

Limitations and Special Considerations

• E/e' has limited accuracy in:
  • Normal subjects 2
  • Patients with heavy annular calcification 2, 4
  • Mitral valve disease, especially severe mitral regurgitation 2, 5
  • Pericardial disease 2
  • Coronary artery disease with regional dysfunction 2
• In patients with mitral annulus calcification, measuring e' at basal segments 2 cm distal to the annulus (e'2) may provide more accurate assessment 4
• In severe mitral regurgitation, mitral deceleration time may be a better indicator of left ventricular end-diastolic pressure than E/e' 5
• The correlation between E/e' and invasively measured filling pressures is modest (pooled correlation coefficient r = 0.56) 2

Practical Tips for Interpretation

• Always interpret E/e' in the context of other echocardiographic parameters 1
• Consider patient's age and clinical context when interpreting results 6
• For more comprehensive assessment of diastolic function, also evaluate:
  • E/A ratio 1
  • Mitral inflow deceleration time 1
  • Left atrial size 1
  • Pulmonary vein flow patterns 1
  • Tricuspid regurgitation velocity (>2.8 m/sec suggests elevated left atrial pressure) 1