Left ventricular (LV) pressure-strain loops (PSLs) have been recently validated as a non-invasive index of myocardial performance. Aim of the present study is to compare average cardiac work (avgCW), positive work (avgPW), negative work (avgNW) and work efficiency (WE) in normal subjects (NOR) and in cardiac resynchronization therapy candidates (CRT).

we included in this study 20 NOR and 61 CRT patients (mean LVEF, GLS and QRS duration: 64±5 vs 27±5%, -23±2 vs –8±3%, 71±21 vs 170±17msec; respectively, all p<0.0001). Strain traces and valvular event times were used for the calculation of LV-PSLs.

with respect to NOR, CRT patients showed an increase in avgNW (329±139 vs 174±67mmHg%, p<0.0001), a significant decrease in avgCW (640±371 vs 2130±206mmHg%, p<0.0001), avgPW (994±378 vs 2338±204mmHg%, p<0.0001), and WE (74±10 vs 93±3, p<0.0001). The attached figure is displaying a typical example of a NOR and of a CRT patient. In CRT, the reduction in GLS (upper panel) is associated with a lengthening of time-to-peak GLS (TTP), particularly in the interventricular septum (IVS) (middle panel). The WE is globally reduced in CRT, but this reduction is greater in the IVS (lower panel).

regional LV-PSLs allow the assessment of global and regional myocardial performance. Their relationship with LV dyssynchrony provides a window for a best understanding of LV mechanics and it will help in defining the most specific parameter for predicting the non-response to CRT.