Diastolic Function of the LV and HFpEF by Echo: ASE 2025 Algorithm

What Changed in the ASE 2025 Update

The document ASE 2025 updates the practical approach from 2016 for assessing LV diastolic function, filling pressure, and diagnosing HFpEF. The main practical idea is to rely less on a single 'magic' indicator and more on the consistency of multiple signs. The algorithm for assessing left atrial pressure includes LA reservoir strain, reducing the proportion of indeterminate conclusions with preserved LVEF.

The algorithm is applied after the standard assessment of study quality, rhythm, LVEF, valvular defects, local contractility disorders, hypertrophy, chamber dilation, and pulmonary pressure. The conclusion should answer two different questions: is there LV diastolic dysfunction and is the LV filling pressure currently elevated.

Minimal Measurement Protocol

For basic assessment, the following are needed: transmitral flow E and A, E/A ratio, E deceleration time, tissue velocities e′ of the septal and lateral fibrous rings, average E/e′, LA volume index, maximum tricuspid regurgitation velocity, and, if image quality permits, longitudinal LA deformation — LA reservoir strain.

Measurements are performed in consistent cardiac cycles. In sinus rhythm, it is important not to average post-extrasystolic complexes. In cases of tachycardia and E and A fusion, the diagnostic value of transmitral flow decreases; in such cases, the conclusion should directly indicate the method's limitation.

Key ASE 2025 Thresholds

LV Filling Pressure Algorithm in Sinus Rhythm

The first step is to assess E/A and E velocity. If E/A ≤0.8 and E ≤50 cm/s, LA pressure is considered normal. In the presence of structural heart disease, this corresponds to grade I diastolic dysfunction: impaired relaxation without evidence of elevated filling pressure.

If E/A ≥2, LA pressure is considered elevated. In a typical clinical situation, this corresponds to grade III diastolic dysfunction — restrictive filling. This conclusion is especially significant in the presence of dyspnea, LA dilation, LV hypertrophy, or other obvious cardiac pathology.

The intermediate zone is E/A >0.8 and <2, as well as E/A ≤0.8 with E >50 cm/s. Here, ASE 2025 recommends integrating additional signs: average E/e′ >14, TR Vmax >2.8 m/s, and LA reservoir strain <18%. If most available signs indicate elevated pressure, it is considered elevated; if most are negative, normal. If data quality is insufficient or there is marked discordance, it is correct to write 'filling pressure cannot be reliably determined.'

Degrees of Diastolic Dysfunction

The degree is not indicated for every patient but for those with proven myocardial disease or structural heart pathology. Normal LVEF does not exclude diastolic dysfunction.

• Grade I — impaired relaxation, LA pressure not elevated: typically E/A ≤0.8 and E ≤50 cm/s.
• Grade II — 'pseudonormal' filling: E/A in the intermediate zone, but additional signs indicate elevated LA pressure.
• Grade III — restrictive filling: E/A ≥2 and elevated LA pressure.

LAVI >34 ml/m² helps confirm the chronic impact of elevated filling pressure but should not be used in isolation: the LA may be enlarged in atrial fibrillation, valvular disease, high cardiac output, and in athletes.

How to Write a Conclusion

A practical conclusion should include not only the degree but also the level of confidence. The optimal formulation: 'LV diastolic dysfunction grade II, LV filling pressure elevated' or 'Signs of impaired LV relaxation, filling pressure not elevated.' If some indicators are unavailable, it is better to state this explicitly: 'TR Vmax not assessed due to lack of reliable TR jet; conclusion based on E/e′ and LA strain.'

Undesirable formulations: 'diastolic dysfunction by E/e′,' 'elevated LA pressure by LAVI,' 'HFpEF by Echo.' Echo confirms the hemodynamic phenotype, but the clinical diagnosis of HFpEF requires symptoms and signs of heart failure.

HFpEF: Role of Echo

HFpEF is considered with LVEF ≥50% and clinical suspicion of heart failure. Echo should show one of two options: elevated filling pressure at rest or inability to exclude it at rest with the need for stress assessment. Normal filling pressure at rest does not exclude HFpEF, as in some patients, pressure increases only with physical exertion.

In the protocol for suspected HFpEF, LVEF, LV mass and geometry, LA size and volume, mitral flow, e′, E/e′, TR Vmax, RV function, and valves are mandatory. LA reservoir strain is useful as an early marker of impaired LA reservoir function and elevated filling pressure, especially when LAVI is not yet increased.

Atrial Fibrillation, Pulmonary Hypertension, and Transplant

ASE 2025 highlights separate algorithms for atrial fibrillation, pulmonary hypertension, and transplanted hearts. In AF, E/A cannot be used because there is no organized A-wave; averaging of several cycles and reliance on parameters less dependent on atrial contraction are required. The conclusion should be cautious with marked RR variability.

In pulmonary hypertension, TR Vmax is no longer a simple surrogate for LA pressure: high TR velocity may reflect pulmonary vascular resistance or right chamber pathology. Therefore, the diagnosis of the postcapillary component should rely on left heart signs — E/e′, LA, mitral flow, and LA strain.

In patients after heart transplantation, atrial geometry, denervation, and surgical technique alter conventional Doppler relationships. Separate recommendations apply to them, rather than the standard degree scale.

AI and Automation

ASE 2025 supports the use of automated measurements and AI as a tool to enhance reproducibility, especially for volumes, tissue Doppler, and strain. However, the algorithm should not become an uncontrolled 'black box': the physician must verify tracings, segmentation quality, selection of cardiac cycles, and clinical consistency of the result.

The main practical rule remains unchanged: in case of parameter discrepancies, first look for a technical reason, then consider rhythm, valves, age-related and structural changes, and only then formulate a conclusion about filling pressure.