Estimated left atrial pressure

LAP / PCWP estimate · Derived from mitral E and annular e′ (card 19) within the ASE 2025 algorithm; PCWP ≈ 1.24 × E/e′ + 1.9

Normal range & thresholds

Normal mean LAP ≤12–15 mmHg. The ASE 2025 guideline reports LAP as a category (normal vs elevated) from e′, E/e′ and TR velocity, adjudicated by LA strain, PV S/D or LAVI, rather than as a number ^[2]. The regression PCWP ≈ 1.24×E/e′ + 1.9 comes from a single validation study and has wide limits of agreement ^[115].

Pathophysiology

E reflects the LA–LV pressure gradient and relaxation; e′ reflects relaxation; their ratio approximates atrial pressure when relaxation is impaired and the annulus moves freely. It is least reliable exactly where the physiology breaks those assumptions: normal hearts, constriction, significant MR, MAC and prostheses ^[2].

Raised by

• Heart failure (either EF), volume overload, mitral disease, restrictive and infiltrative cardiomyopathy, HCM

Lowered by

• Hypovolaemia, over-diuresis; healthy young hearts (E/e′ low)

Technique & pitfalls

• Use average E/e′ where valid; lateral only in LBBB, pacing, post-cardiac-surgery and PH ^[2].
• Present it as a direction ("elevated") and quote the algorithm, not a precise mmHg value.
• Exercise E/e′ ≥15 with TR >3.4 m/s supports HFpEF when resting data are normal ^[105,106].

Pseudo-change & artefact

• MAC, rings and prostheses tether the annulus (false high); constriction and primary MR with normal EF give false low values ^[2,57].
• Diuresis changes E within hours.

Treatment thresholds

• Elevated LAP with symptoms supports a diagnosis of HFpEF within HFA-PEFF and the ASE 2025 HFpEF section; SGLT2 inhibition is supported (DELIVER) ^[2,82,101].
• Guides decongestion targets in acute heart failure.

Next step

• Next: complete the two-step algorithm (card 19), then LA strain (card 60).
• Then: diastolic stress echo or invasive haemodynamics if management depends on it ^[2,106].

Drugs

Loop diuretics, nitrates, SGLT2 inhibitors and ARNI lower it; fluids, NSAIDs and steroids raise it.

Reversibility

Falls within hours of decongestion — a filling-pressure change, not a change in the myocardium.