Non-invasive myocardial work

GWI, GCW, GWW, GWE · Speckle-tracking GLS in three apical views + brachial BP + valve event timing (vendor pressure–strain loop)

Normal range & thresholds

EACVI NORRE reference values: GWI 1896 ± 308 mmHg% (range ≈1270–2428), GCW 2232 ± 331 mmHg%, GWW median ≈79 mmHg%, GWE median ≈96% (lower limit ≈91%) ^[160].

Pathophysiology

Strain falls when afterload rises, even with normal contractility. Myocardial work combines strain with an estimated LV pressure curve, giving the area of a pressure–strain loop validated against invasive pressure–volume work and regional glucose metabolism ^[159]. Constructive work is shortening in systole; wasted work is stretching in systole or shortening after valve closure.

Raised by

• GWI above normal: hypertension, AS (high load with preserved deformation)

Lowered by

• GWI/GCW low: systolic dysfunction, cardiomyopathies, infarction
• GWE low: dyssynchrony (LBBB), ischaemia, scar

Technique & pitfalls

• Accurate GLS tracking and valve timing; BP at the time of acquisition; same vendor serially ^[90,160].

Pseudo-change & artefact

• Brachial vs LV pressure in AS/LVOT obstruction (add gradient when the software allows); vendor dependence.

Treatment thresholds

No guideline threshold yet; research use in CRT selection, HCM and hypertension. Report as supportive.

Next step

• Interpret with GLS (card 10) and coupling.

Drugs

Afterload reduction lowers GWI without changing contractility — interpret with BP.

Reversibility

Tracks the underlying myocardium and load.