This figure summarizes the indications provided by parameters that showed a statistically significant improvement in the corresponding tested configurations. The variations (%) are shown for each parameter with reference to the basal condition of LBBB. VTI and ET were excluded because they did not show any statistically significant improvement in any of the tested AV intervals. DFT significantly increased at AV3 and AV4. Interventricular delay (IVD) statistically decreased at every tested configuration in the fusion band, even if the optimal clinical values corresponded to AV3 and AV4. MR showed a significant and clinically important reduction at AV3 and AV4. Ts-SD-12-ejection improved at AV1, AV2 and AV3 and the corresponding mean value was statistically significant compared to LBBB. MPI significantly decreased at AV2, AV3 and AV4. EF significantly increased in the fusion band with the best values corresponding to AV3 and AV4. In accordance with these indications it seems reasonable to programme single-site LV pacing at the AV intervals within the fusion band, mainly within the shorter half of it. Indeed, setting a value of AV interval inside the fusion band improves cardiac function in comparison with LBBB. At the shortest AV intervals of the band there is the largest overlapping among the indications provided by the measured parameters.