Geert Kleinnibbelink

Chapter 2 44 RV area (cm 2 ) RV longitudinal strain (%) ESA EDA a. ESslope b. Sslope c. Peak strain d. Uncoupling ED e. Uncoupling LD f. Uncoupling g. EDslope h. LDslope 0 0 -21 a b c e d 100% of EDA 40% of EDA 25 f g h Figure 2. Schematic overview of the RV strain-area loop and the derived characteristics. The black line represents the strain-area loop, the thick part represents the systolic phase and the thin line the systolic phase. EDA, end-diastolic area. ESA, end-systolic area. ESslope, early systolic slope. Sslope, systolic slope. Uncoupling ED, uncoupling end-diastolic. Uncoupling LD, uncoupling late diastolic. In order to obtain intra-observer variability, strain-area loops were re-analysed in 20 randomly selected echocardiograms (n=10 rest, n=10 stress). For all strain-area loop characteristics intra-class correlation coefficient (ICC) and Bland-Altman limits of agreement (LOA) analysis were performed. 38 Statistical analysis Statistical analysis was performed using SPSS Statistics 25 (SPSS Inc., Chicago, IL, VS). All parameters were visually inspected for normality and tested with Shapiro-Wilk normality tests. Continuous variables were reported as mean ± standard error of the mean (SEM) and categorical variables were presented as proportions. Linear mixed models analysis for