Effective arterial elastance

Ea · Derived: Ea = end-systolic pressure / SV, with ESP ≈ 0.9 × brachial systolic pressure (+ AS mean gradient for LV pressure)

Normal range & thresholds

Healthy adults ≈1.5–2.5 mmHg/mL (higher in small bodies; often indexed to BSA). Values rise with age, hypertension, arterial stiffening and HFpEF ^[109,161].

Pathophysiology

Ea lumps the three components of arterial load — resistance, compliance and wave reflection — into one slope on the pressure–volume plane: the line from end-diastolic volume at zero pressure to the end-systolic point. It is the arterial half of coupling: how much end-systolic pressure the arteries return for each millilitre ejected ^[109,112].

Raised by

• Hypertension, ageing, diabetes, CKD (arterial stiffening)
• HFpEF (combined ventricular–arterial stiffening) ^[161,162]
• Vasoconstriction in shock; small stroke volume (low-flow states)

Lowered by

• Vasodilation (sepsis, vasodilator drugs), anaemia, AV fistula
• Aortic regurgitation (runoff), pregnancy

Technique & pitfalls

• ESP ≈ 0.9 × SBP is validated against invasive end-systolic pressure ^[109]; add the AS mean gradient to model LV pressure.
• Take SV from LVOT Doppler or biplane volumes — state which.
• Measure BP at the time of the echo.

Pseudo-change & artefact

• Brachial pressure amplification overestimates central pressure in the young.
• SV errors (LVOT diameter) propagate inversely.
• Significant MR: total SV ≠ forward SV — use forward SV for arterial load.

Treatment thresholds

No treatment threshold. Ea describes afterload for the coupling assessment (card 50) and explains why BP control improves SV and symptoms in afterload-sensitive ventricles ^[157].

Next step

• Combine with Ees → Ea/Ees (card 50); with SAC and Zva (cards 51–52) to separate resistive, pulsatile and valvular load.

Drugs

Lowered by vasodilators, RAAS blockade, dihydropyridine calcium blockers, ARNI; raised by vasopressors.

Reversibility

Resistive component changes in minutes; the stiffness component changes slowly with long-term BP control.