Myocardial Work by Echocardiography: Principles and Applications in Clinical Practice

Figure 1. LV global longitudinal strain data, measured using the R-wave onset in the electrocardiogram as a common time reference (left panel), are combined with estimated LV pressure curve. After measuring peak arterial pressure with a cuff manometer, an empiric, normalized reference curve is adjusted according to LV duration of the isovolumetric and ejection phases, defined by timing of aortic and mitral valve events by echocardiography (central panel). On the right panel, representative trace showing LV pressure-strain loop (up), 17-segment bull’s-eye representation of MW index (middle) and MW efficiency (bottom). AVC = aortic valve closure; AVO = aortic valve opening; GWI = global work index; GWE = global work efficiency; LV = left ventricular; LVP = left ventricular pressure; MVC = mitral valve closure; MWO = mitral valve opening.

Figure 2. Myocardial work indices in a patient with inferior ST-elevation myocardial infarction. Pressure-strain loop of the basal segment of the inferior wall showed post-systolic shortening, early marker of ischemia, which translate into an important decrease of MW index (A,B), global work efficiency (C) and global longitudinal strain (D) in the territories supplied by the obstructed right coronary artery. LVP = left ventricular pressure.

Figure 3. Pressure-strain loop (A) and 17-segment bull’s-eye representation of GWI (B) in a patient with cardiac amyloidosis, showing a reduced loop area, representing a reduced stroke work developed by the ventricle, and significant impairment of MW index in the basal segments. In endurance athletes MWE is an early predictor of physiologic remodeling in baseline examination (C,D). GWI = global work index; GWE = global work efficiency; LVP = left ventricular pressure.

Figure 4. Pressure-strain loop (A,C) and 17-segment bull’s-eye representation of global work index (B,D) in a patient with severe aortic stenosis before and after transcatheter aortic valve implantation, demonstrating a significant reduction of stroke work, and therefore GWI, as a consequence of the reduced afterload post valve replacement. GWI = global work index; LVP = left ventricular pressure; TAVR = transcatheter aortic valve replacement.