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E/A Ratio Grading (Diastolic Function): Explanation and Clinical Context The E/A ratio is obtained from Doppler echocardiography by dividing the peak early (E) mitral inflow velocity by the peak atrial (A) contraction velocity. It is a cornerstone for evaluating left ventricular diastolic function. Grade I (E/A < 0.8) represents impaired relaxation, commonly seen in early diastolic dysfunction and aging. Grade II (E/
E over e Ratio: Clinical Explanation and Interpretation The E over e ratio provides an indirect estimation of left ventricular filling pressures by combining transmitral inflow velocity with myocardial relaxation velocity measured through tissue Doppler imaging. The early transmitral flow velocity rises when left atrial pressure increases, while the e prime velocity decreases when myocardial relaxation is impaired. T
E/e' Ratio: Explanation and Clinical Context The E over e prime ratio is one of the most widely used echocardiographic indices to estimate left ventricular filling pressure. The E wave represents early diastolic transmitral flow velocity which increases when the left atrial pressure rises. The e prime velocity is measured at the mitral annulus and reflects the intrinsic rate of myocardial relaxation. Since e prime de
Epicardial Fat Volume (CT Quantification): Explanation and Clinical Context Epicardial fat volume (EFV) represents the total volume of adipose tissue located between the myocardium and the visceral layer of the pericardium, quantifiable via non-contrast or contrast-enhanced cardiac CT. EFV is calculated by summing the areas of epicardial fat on each slice (cm²) multiplied by the slice thickness (cm) and the number of
Extracellular Volume Fraction (ECV) by MRI: Explanation and Clinical Context Extracellular Volume Fraction (ECV) quantifies the proportion of the myocardial tissue that is extracellular space, providing a non-invasive estimate of diffuse myocardial fibrosis and infiltration. The calculation uses pre- and post-contrast T1 values of myocardium and blood, corrected for the patient's hematocrit: ECV = (1 - Hct) × (ΔR1_my
e' Average: Explanation and Clinical Context The e prime average value represents the combined early diastolic mitral annular velocity obtained from the lateral and septal annulus using tissue Doppler imaging. This index provides a quantitative assessment of myocardial relaxation, which is a key determinant of left ventricular diastolic function. Because the lateral annulus typically exhibits higher velocities and th