From the Guidelines
Diastolic dysfunction is graded based on the E/A ratio as follows: Grade I (mild) with an E/A ratio ≤ 0.8, Grade II (moderate) with an E/A ratio between 0.8 and 2.0, and Grade III (severe) with an E/A ratio ≥ 2.0, as recommended by the American Society of Echocardiography and the European Association of Cardiovascular Imaging 1, 2.
Grading of Diastolic Dysfunction
The grading of diastolic dysfunction is based on the E/A ratio, which measures the relationship between early (E) and late (A) diastolic filling velocities on echocardiography.
- Grade I (mild) diastolic dysfunction is characterized by an E/A ratio ≤ 0.8, indicating impaired relaxation, with a peak E velocity of ≤50 cm/sec, and a mean left atrial pressure (LAP) that is either normal or low 1.
- Grade II (moderate) diastolic dysfunction has a pseudonormal pattern with an E/A ratio between 0.8 and 2.0, which requires additional parameters like tissue Doppler to differentiate from normal filling 2.
- Grade III (severe) diastolic dysfunction presents with a restrictive pattern showing an E/A ratio ≥ 2.0, indicating elevated left atrial mean pressure and a shortened deceleration time (<160 msec) 1, 2.
Additional Parameters for Accurate Assessment
For accurate assessment of diastolic dysfunction, the E/A ratio should be evaluated alongside other parameters, including:
- Tissue Doppler (e' velocity)
- E/e' ratio
- Left atrial volume
- Pulmonary vein flow patterns These parameters help to guide treatment decisions for conditions like heart failure with preserved ejection fraction 1, 2.
Clinical Application
In clinical practice, the grading of diastolic dysfunction based on the E/A ratio and additional parameters helps clinicians to understand the severity of left ventricular filling abnormalities and to guide treatment decisions 1, 2.
From the Research
Grading of Diastolic Dysfunction
The grading of diastolic dysfunction according to the E/A ratio is as follows:
- Grade I (mild diastolic dysfunction): E/A ratio < 0.8, indicating impaired relaxation 3
- Grade II (moderate diastolic dysfunction): E/A ratio between 0.8 and 1.5, indicating pseudonormalization 4, 5
- Grade III (severe diastolic dysfunction): E/A ratio > 1.5, indicating restrictive filling 4, 5
- Grade Ia: a distinct group of patients with E/A ratio < 0.8 and elevated filling pressures (septal E/e' ≥15, lateral E/e' ≥12, average E/e' ≥13) 3
Key Parameters for Diastolic Function Assessment
Some key parameters used to assess diastolic function include:
- E/A ratio: early to late diastolic transmitral flow velocity 6, 7, 4, 3, 5
- E/e' ratio: early diastolic mitral annular tissue velocity to early diastolic transmitral flow velocity 6, 7, 4, 3
- Left atrial volume index (LAVI) and left atrial dimension 3, 5
- Deceleration time and isovolumic relaxation time (IVRT) 7, 3
- Pulmonary vein flow and tissue Doppler of the mitral annulus 7