Statistics

We used SPSS 24.0 software (IBM Corporation, Armonk, USA) to perform the statistical tests. Data are presented as the mean and standard deviation (SD) of the intervention results. A value of p < 0.05 was considered statistically significant. To create the graphics and to visualize the data, paint.net (Rick Brewster, dotPDN, L.L.C., San Francisco, USA), RStudio²⁷ and Prism (PRISM 8.1, GraphPad Software, San Diego, USA) were used.

The effect of the intervention type (VLoad, PLoad) on Ees and r² of different ESPVRs was analyzed by two-way variance analysis with Dunnett´s post hoc test for multiple comparisons. Variance analysis for repeated measurements was used to describe the significant effects of the intervention type and location on the ESPVR and PRSW values and on other hemodynamic parameters. A T-test was used for post hoc analysis of the differences between the site of intervention (ASC vs. DESC), and Dunnett´s correction was used for significant changes from the normal loading condition. Finally, we investigated the correlation between different values of Ea, Ees and V0 using Pearson’s correlation coefficient.