Diastolic Function of the RV on EchoCG: E/A, e′, and Hepatic Veins

Why Assess RV Diastole Separately

In the updated ASE 2025 guidelines for the right heart, the diastolic function of the RV is highlighted as a separate protocol block, rather than an optional appendix to size and systolic assessment. The document emphasizes that right ventricular filling depends on myocardial relaxation, RV compliance, right atrial pressure, respiratory fluctuations, and interaction with the left heart. Therefore, the isolated value of a single Doppler parameter should not replace an integrated conclusion.

Practical minimum according to ASE 2025: transtricuspid pulsed-wave Doppler, tissue Doppler e′ at the lateral tricuspid annulus with E/e′ calculation, and hepatic vein analysis. These data are especially useful in pulmonary hypertension, tricuspid valve pathology, RV myocardial diseases, post-right heart surgeries, and suspected increased RV filling pressure.

Key Classification ASE 2025

Transtricuspid Flow: What to Measure

Transtricuspid flow is recorded using pulsed-wave Doppler from the apical four-chamber view, aligning the beam with the direction of diastolic flow through the tricuspid valve. Early diastolic velocity E, atrial velocity A, E/A ratio, and deceleration time of the E-wave, denoted as DT, are measured. It is important to indicate not only the E/A ratio but also the filling pattern in the conclusion, as the same E/A can correspond to different filling pressures.

With E/A <0.8, the ASE algorithm classifies the pattern as impaired RV relaxation. This typically reflects reduced early filling and relatively increased atrial contribution. For E/A 0.8–2.1, the ratio alone is insufficient: this range can be close to physiological or pseudonormal. In this zone, E/e′ and hepatic veins are needed. For E/A >2.1, DT should be assessed: a combination with DT <120 ms corresponds to restrictive filling.

e′ of the Lateral Tricuspid Annulus and E/e′

The e′ velocity is obtained using tissue Doppler at the lateral segment of the tricuspid annulus. It reflects early diastolic motion of the annulus and is used together with the E-wave of transtricuspid flow. In the ASE 2025 algorithm, the key numerical criterion is not the isolated e′ but the E/e′ ratio.

The threshold E/e′ >6 is used to identify pseudonormal RV filling if E/A is in the range of 0.8–2.1. In other words, with an outwardly unremarkable change in E/A, an elevated E/e′ shifts the interpretation towards increased filling pressure and Grade II diastolic dysfunction. It is advisable to specify the measurement location of e′ in the protocol, as the lateral tricuspid annulus should be compared, not averaged or left ventricular values.

Hepatic Veins: Confirmation of Filling Pressure

Flow in the hepatic veins is an important component of right ventricular diastole, as it reflects the interaction of the right atrium, tricuspid valve, and venous return. In normal interpretative logic, the systolic and diastolic phases of antegrade flow, as well as the influence of respiration and rhythm, are evaluated. For the RV diastolic function algorithm, the decisive feature is diastolic flow predominance.

If E/A is 0.8–2.1 and diastolic predominance is found in the hepatic veins, ASE 2025 considers this as confirmation of a pseudonormal pattern. This result is especially valuable when E/e′ is borderline reproducible or tissue Doppler is technically limited. However, hepatic veins should not be interpreted in isolation in cases of significant tricuspid regurgitation, arrhythmia, or unstable respiratory patterns.

How to Formulate a Conclusion

The optimal formulation should include the grade, criteria used, and limitations. For example: RV diastolic dysfunction Grade I, transtricuspid E/A <0.8. Another option: RV diastolic dysfunction Grade II, E/A 0.8–2.1 combined with E/e′ >6. For a restrictive pattern, both parts of the criterion should be explicitly stated: E/A >2.1 and DT <120 ms.

If data are incomplete or contradictory, it is safer to write: RV diastolic function cannot be reliably classified based on available Doppler data. This is better than assigning a grade based on a single questionable measurement. In such cases, factual indicators and factors affecting reliability should be described.

Typical Pitfalls

• Atrial Fibrillation. The A-wave is absent, so E/A and standard staging by the A-component are not applicable.
• Significant Tricuspid Regurgitation. It alters atrial pressure and hepatic venous flow, so signs may reflect valvular hemodynamics, not just RV relaxation.
• Tachycardia. Fusion of E and A complicates E/A and DT calculation.
• Incorrect Doppler Angle. Underestimation of velocities can mimic impaired relaxation.
• Respiratory Variability. The right heart is sensitive to the respiratory phase; analysis should consider recording stability.

Place in the Full Right Heart Protocol

RV diastolic function does not replace the assessment of RV size, right atrium, RV function, pulmonary artery pressure, inferior vena cava, and tricuspid valve. It adds information about filling and pressure in the right heart. Clinically significant situations are when systolic indicators are still moderately altered, but signs of increased filling pressure appear.

In a practical protocol, it is convenient to have a separate line: RV diastolic function. Below it—E/A, DT, e′ of the lateral tricuspid annulus, E/e′, and the nature of hepatic venous flow. This format makes the study reproducible and aligns with ASE 2025 logic: first measurements, then integrated classification.

Short Algorithm for the EchoCG Office

1. Record transtricuspid PW Doppler and measure E, A, E/A, and DT.
2. If E/A <0.8, indicate impaired relaxation, Grade I.
3. If E/A 0.8–2.1, add E/e′ and hepatic veins.
4. If E/e′ >6 or diastolic predominance in hepatic veins, Grade II.
5. If E/A >2.1, check DT; if DT <120 ms, Grade III, restrictive pattern.
6. In cases of irregular rhythm, wave fusion, or poor visualization, indicate limitations and avoid forcing classification.