## 3 Results
### Conventional Echocardiographic Parameters  
Table 2 shows comparison of echocardiographic parameters between the three study groups (control, non-worsening PAH children, worsening PAH children). Regarding conventional echocardiographic parameters, significant differences were observed in RV-FAC, RV-MPI, RV S/D, S', LV-EI between non-worsening PAH children and control group. We performed the receiver-operator characteristic analysis for all these parameters, and the reference group was the non-worsening PAH group. The ROC curves are presented in Figure 2. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Variable**} & \multirow{2}{*}{\begin{tabular}{c} **Control** \\ **(n = 18)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Non-Worsening** \\ **PAH Children** \\ **(n = 10)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Worsening** \\ **PAH Children** \\ **(n = 7)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **P1** \\ **(nw vs. c)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **P2** \\ **(w vs. c)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **P3** \\ **(w vs. nw)** \\ \end{tabular} } \\ \hline TR (mmHg) & NA & 89.54 \(\pm\) 32.05 & 95.44 \(\pm\) 12.73 & NA & NA & 0.585 \\ \hline PAPm (mmHg) & NA & 61.900 \(\pm\) 20.19 & 57.00 (51.00, 59.00) & NA & NA & 0.766 \\ \hline Indexed RV-ED area (cm\({}^{2}\)) & 13.31 \(\pm\) 5.03 & 14.62 \(\pm\) 3.88 & 17.55 \(\pm\) 6.30 & 1.000 & 0.133 & 0.623 \\ \hline Indexed RV-ES area (cm\({}^{2}\)) & 6.61 (5.54, 8.58) & 9.98 \(\pm\) 3.99 & 11.78 \(\pm\) 4.68 & 0.214 & 0.017 & 0.882 \\ \hline RV-FAC & 0.45 \(\pm\) 0.05 & 0.33 \(\pm\) 0.13 & 0.33 \(\pm\)0.06 & 0.002 & 0.007 & 1.000 \\ RV MPI & 0.12 \(\pm\) 0.07 & 0.37 \(\pm\) 0.18 & 0.33 (0.28, 0.70) & 0.001 & 0.0001 & 0.492 \\ \hline TAPSE (cm) & 2.16 \(\pm\) 0.46 & 1.62 \(\pm\) 0.47 & 1.62 \(\pm\) 0.53 & 0.015 & 0.023 & 1.000 \\ \hline RV S (ms) & 355.63 \(\pm\) 33.76 & 377.27 \(\pm\) 33.23 & 397.22 \(\pm\) 55.72 & 0.457 & 0.037 & 0.803 \\ \hline RV D (ms) & 397.12 \(\pm\) 97.63 & 283.35 \(\pm\) 69.74 & 260.00 (250.58, 347.20) & 0.007 & 0.056 & 1.000 \\ \hline RV S/D ratio & 0.85 (0.77, 1.12) & 1.39 \(\pm\) 0.31 & 1.38 \(\pm\) 0.33 & 0.001 & 0.001 & 1.000 \\ \hline Indexed RA area (cm\({}^{2}\)) & 8.38 \(\pm\) 1.35 & 10.67 (9.60, 13.79) & 11.38 (10.20, 16.27) & 0.945 & 0.018 & 0.268 \\ \hline Diam 1 LV (cm) & 3.94 \(\pm\) 0.65 & 4.24 \(\pm\) 0.63 & 4.05 \(\pm\) 0.46 & 0.602 & 1.000 & 1.000 \\ \hline Diam 2 LV (cm) & 3.91 \(\pm\) 0.55 & 3.12 \(\pm\) 0.40 & 2.90 \(\pm\) 0.59 & 0.001 & 0.0001 & 1.000 \\ \hline LV-EI & 1.00 \(\pm\) 0.07 & 1.26 (1.19, 1.63) & 1.44 \(\pm\) 0.29 & 0.001 & 0.0001 & 1.000 \\ \hline S’ (cm/s) & 13.43 \(\pm\) 1.60 & 10.92 \(\pm\) 2.07 & 10.44 \(\pm\) 2.68 & 0.006 & 0.002 & 1.000 \\ \hline TMAD lat (mm) & 19.08 \(\pm\) 3.88 & 14.90 \(\pm\) 2.37 & 11.64 \(\pm\) 2.84 & 0.006 & 0.0001 & 0.106 \\ \hline TMAD sept (mm) & 12.29 \(\pm\) 2.25 & 8.51 \(\pm\) 1.82 & 7.63 \(\pm\) 2.09 & 0.0001 & 0.0001 & 1.000 \\ \hline TMADmid (mm) & 16.38 \(\pm\) 2.96 & 12.15 \(\pm\) 2.13 & 10.44 \(\pm\) 3.59 & 0.001 & 0.0001 & 0.603 \\ \hline TMADm\% & 23.70 \(\pm\) 3.62 & 18.13 \(\pm\) 2.87 & 13.51 \(\pm\) 2.84 & 0.0001 & 0.0001 & 0.010 \\ \hline \end{tabular}
\end{table} 
Table 2: Comparison of echocardiographic parameters between the study groups (control, non-worsening PAH children and worsening PAH children). The same significant differences were observed in RV-FAC, RV-MPI, RV S/D, S', LV-EI between the worsening group and control group. In addition, comparing these two last groups, we also found a statistical difference in the indexed RV and RA area, explained by the fact that in the worsening group, the right ventricle was more enlarged than in the non-worsening group (Table 2). We have also performed the receiver-operator characteristic analysis for all these parameters, and the reference group was the worsening PAH group.