Left atrial stiffness index

E/e′ ÷ LASr · Average E/e′ divided by LA reservoir strain (%)

Normal range & thresholds

Higher values indicate a stiff atrium. In the original validation it discriminated patients with diastolic heart failure from controls, with a cut-off near 0.26 commonly quoted ^[116].

Pathophysiology

E/e′ stands in for LA pressure and reservoir strain for LA volume change; their ratio is a pressure-per-deformation analogue of atrial stiffness. A stiff, fibrotic atrium transmits pressure to the lungs and predicts atrial fibrillation.

Raised by

• HFpEF, AF history, mitral disease, amyloid, ageing

Lowered by

• Healthy compliant atria

Technique & pitfalls

• Same-beat or averaged measurements; vendor-consistent LA strain ^[163].

Pseudo-change & artefact

• All E/e′ limitations; vendor differences in strain.

Treatment thresholds

No guideline threshold; supportive in HFpEF work-up ^[2,101].

Next step

• LA reservoir strain (card 60) and diastolic stress testing.

Drugs

Decongestion and rhythm control lower it.

Reversibility

Partly reversible when filling pressure falls; fibrosis is not.