Diastology: Use E/e’ to Estimate Left Atrial Pressure

• POCUS diastology answers one ED question: Is left atrial pressure (LAP) elevated right now? (not “diagnose diastolic dysfunction”)
• E/e’ estimates LAP using mitral inflow E (PW Doppler) and annular e’ (TDI) from an apical 4-chamber view
• Interpretation: E/e’ ≥ 14 → likely elevated LAP (supports cardiogenic pulmonary edema); ≤ 8 → LAP likely normal; 8–14 → indeterminate
• Fast + actionable: With a decent apical view, E and e’ can be captured in ~60 seconds to guide diuresis/afterload reduction vs non-cardiac pathways
• Use context: E/e’ performs best in reduced EF and can be confounded by MR/MS, tachycardia, and BiPAP/PEEP

A formal echocardiographic diagnosis of diastolic dysfunction is multivariable, nuanced, and not an ED priority in most acute dyspnea cases.

In the emergency setting, the bedside question that changes management is simpler:

Is left atrial pressure (LAP) elevated right now?

Elevated LAP is the physiologic substrate for cardiogenic pulmonary edema and the target for therapies like diuresis and afterload reduction. “POCUS diastology” is a focused ultrasound approach that helps you answer that question quickly—often faster than CXR, BNP, or a “CHF vs pneumonia” radiology impression.

POCUS diastology ≠ chronic diagnosis. It’s a real-time estimate of filling pressure to guide acute resuscitation.

A 72-year-old obese woman presents with severe dyspnea. EMS placed her on BiPAP for hypoxia. She’s uncomfortable, with bibasilar crackles and faint wheezing.

Vitals: BP 166/98, HR 110, RR 22, SpO₂ 86%.

Your differential is broad:

• Pneumonia?
• COPD exacerbation?
• Flash pulmonary edema?

CXR: “Atypical pneumonia vs pulmonary edema” (not helpful)

Labs: WBC 14.1, pBNP 320 (still not helpful)

Your bedside ultrasound:

• The IVC is dilated → tempting to anchor on CHF

  But you pause: COPD on BiPAP can also dilate the IVC via increased intrathoracic pressure and RV loading.

You obtain a cardiac view:

• EF looks normal → but that doesn’t rule out elevated filling pressures (hello HFpEF physiology)

Does this settle it? Can we give this patient bronchodilators, steroids and antibiotics?

You’re not trying to label the patient with “diastolic dysfunction.”

You’re asking one resuscitation question:

Is LAP elevated in this moment?

If yes → cardiogenic pulmonary edema becomes much more likely and diuresis/afterload reduction moves up the priority list.

If no → search hard for non-cardiogenic causes (COPD, pneumonia, PE, ARDS, etc.).

Diastolic filling depends on:

• Intrinsic: LV relaxation, LV compliance, atrial contraction
• Extrinsic: pericardial pressure, RV function, intrathoracic pressure (BiPAP), volume status

When the LV is stiff/noncompliant, blood backs up into the LA → LAP rises → pressure transmits to the pulmonary vasculature → pulmonary edema.

This can happen even with normal EF.

To estimate LAP, you measure:

• E wave: early diastolic mitral inflow velocity (PW Doppler)
• e’ wave: early diastolic mitral annular tissue velocity (TDI)

Then calculate:

This ratio is used as a noninvasive estimate of LV filling pressures and correlates with formal echocardiography-derived estimates.

Example formula cited in echo literature:

LAP ≈ (1.24 × E/e’) + 1.9

Important nuance (keep your wording tight):

E/e’ can be used in both preserved and reduced EF, but performance is generally stronger in reduced EF. In normal EF, treat E/e’ as a high-value clue rather than a standalone verdict—especially in the intermediate zone.

A lot of POCUS users avoid Doppler because it feels “advanced.”

Here’s the reality:

If you can obtain a decent apical 4-chamber, you can obtain E and e’.

Once the view is good, capturing waveforms is straightforward.

You obtain your images:

• E wave = 110 cm/s
• e’ = 5 cm/s
• E/e’ = 22

That strongly supports elevated LAP and therefore cardiogenic pulmonary edema physiology.

Action: You prioritize IV diuresis (and consider afterload reduction as appropriate), while avoiding reflexive bronchodilators/steroids/antibiotics as your default path.

Result: The patient’s breathing improves within 30 minutes—less diagnostic drift, fewer unnecessary meds, and potentially fewer intubations.

1. What is E/e’ on ultrasound?
   E/e’ is the ratio of mitral inflow (E wave) to mitral annular tissue velocity (e’). It’s used to estimate LV filling pressures and left atrial pressure.
2. What E/e’ value suggests elevated filling pressure?
   An E/e’ ≥ 14 supports elevated LAP; ≤ 8 suggests normal LAP; 8–14 is indeterminate and should be integrated with other findings.
3. Can E/e’ be used with preserved EF (HFpEF)?
   Yes, but it’s generally less reliable than in reduced EF. In HFpEF, treat E/e’ as a strong clue—especially when very high—while integrating the full clinical picture.
4. Why not just use BNP or CXR?
   BNP and CXR can be nonspecific or delayed. E/e’ targets physiology (filling pressure) at the bedside when it matters most.
5. Why aren’t we talking about the E/A ratio?
   The E/A ratio can be misleading because of the phenomenon of pseudonormalization. In grade 2 diastolic dysfunction the E/A ratio reverts from abnormal to normal; this can be a clinical trap.

• POCUS diastology doesn’t diagnose chronic diastolic dysfunction—it estimates real-time LAP
• E/e’ ≥ 14 supports elevated LAP and cardiogenic pulmonary edema physiology
• E/e’ ≤ 8 makes elevated LAP less likely—pursue alternative causes of dyspnea
• With a decent apical view, E and e’ are obtainable fast
• The right call can be diuretics instead of antibiotics, and a better trajectory for your patient

When you suspect pulmonary edema, don’t stop at lung ultrasound or BNP. Reach for your apical view, capture E and e’, and ask the real question:

With POCUS diastology, you’ll have the answer in under 60 seconds.

1. Greenstein YY, Mayo PH. Evaluation of Left Ventricular Diastolic Function by the Intensivist. Chest. 2018;153(3):723-732. PMID: 29113815
2. Del Rios et al. Emergency physicians used average e’ (<9 cm/s) alone to assess for diastolic dysfunction. Compared to cardiology standard, agreement was 85.4% (κ = 0.74). Shows the feasibility of streamlined approaches in real ED practice. J Ultrasound Med. 2018 May;37(5):1237-1243
3. ASE/EACVI 2025 Guidelines – The most recent comprehensive guidance on echocardiographic assessment of diastolic function, re-emphasizing the centrality of E/e’ in estimating LAP. J Am Soc Echocardiogr. 2025 Apr;38(4):278-317

Post Peer Reviewed By: Marco Propersi, DO (X: @Marco_propersi), Mark Ramzy, DO (X/IG: @MRamzyDO), Jailyn Avilla, MD (Insta: @jailyn_avi)