Left atrial reservoir strain

LASr · LA-focused apical 4- (and 2-) chamber views, speckle tracking with QRS (R-R) zero reference

Normal range & thresholds

Normal ≈39% (95% CI 38–41%) in a meta-analysis of 2,542 healthy subjects ^[164]. ≤18% adjudicates elevated LA pressure in step 2 of the ASE 2025 algorithm ^[2]. Report the zero reference (R-R vs P-P) and vendor ^[163].

Pathophysiology

The atrium works in three phases: reservoir (filling while the mitral valve is closed), conduit and booster pump. Reservoir strain falls as LA pressure and stiffness rise and as atrial fibrosis develops — often before the atrium enlarges, which is why adding LASr to LAVI improves detection of diastolic dysfunction ^[165].

Raised by

• Athletes, young hearts; hyperdynamic states

Lowered by

• Elevated filling pressure (HFpEF, HFrEF), atrial myopathy, AF (especially persistent), amyloid, mitral disease

Technique & pitfalls

• LA-focused views; exclude pulmonary veins and appendage from the ROI; frame rate 50–80 fps.
• EACVI/ASE/industry standards: R-R gating, peak positive strain = reservoir ^[163].

Pseudo-change & artefact

• Foreshortened LA, poor tracking of the thin wall, vendor/software differences, AF cycle-length variation.

Treatment thresholds

• Diastolic function: LASr ≤18% → elevated LAP when primary variables disagree ^[2].
• Supports HFpEF diagnosis; predicts incident AF and outcome.

Next step

• Integrate in the two-step algorithm (card 19); diastolic stress echo if resting data equivocal ^[105].

Drugs

Decongestion and rhythm control improve it; improvement after AF ablation predicts maintenance of sinus rhythm.

Reversibility

Pressure component reversible; fibrotic component not.