## 3 Results
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Length**} & \multicolumn{2}{c}{**No Discard**} & **Discard** \\ \cline{2-6}  & **Range** & **Mean \(\pm\) Std** & **Range** & **Mean \(\pm\) Std** \\ \hline
**1 s** & [0.075–0.998] & 0.561 \(\pm\) 0.120 & [0.075–0.963] & 0.559 \(\pm\) 0.113 \\
**12** & [0.122–1.000] & 0.600 \(\pm\) 0.101 & [0.122–0.958] & 0.595 \(\pm\) 0.091 \\
**4 s** & [0.092–1.000] & 0.631 \(\pm\) 0.072 & [0.124–0.942] & 0.621 \(\pm\) 0.058 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Determinism statistical descriptors analysis results for 1, 2, and 4 s length segments, with and without discards. The values reported were obtained by averaging among CFAE. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **1s** & \(\Delta\)**CV 1 s** & **2 s** & \(\Delta\)**CV 2 s** & **4 s** & \(\Delta\)**CV 4 s** \\ \hline
**DET** & 23.3\% & \(-\)15.6\% & 19.1\% & \(-\)22.8\% & 13.3\% & \(-\)47.9\% \\
**SE** & 26.6\% & \(-\)16.1\% & 20.5\% & \(-\)20.1\% & 13.9\% & \(-\)42.2\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Intra-recording CV of DET and SE for 1, 2, and 4 s length segments, and the respective variation of the CV (\(\Delta\)CV) introduced by discarding low-quality segments. for the DET, it was accepted in two cases with no discard and in one case with discard. For the 4 s length, the null hypothesis was accepted in seven cases (one for the SE with discard, one for the DET with no discard, and five for the DET with discard); however, once the box plots were visualized to verify the accuracy of the results, the median values had demonstrated differences. The inaccuracy found for the 4 s length datasets are justified by the fact that the sample size is small, and therefore, the test does not follow a \(\chi^{2}\) distribution. With respect to the results for the discrimination between the CFAE of the ParAF versus PerAF, the mean and standard deviation values resulted by applying the SE and DET to the 1, 2, and 4 s length datasets, reported in Table 5 and organized by the AF type. The AFCL and the DF obtained from the 16 s length CFAEs demonstrated values of AFCL with an average and standard deviation of 7.75 \(\pm\) 1.56 in ParAF and 7.01 \(\pm\) 1.46 in PerAF, while the DF had, respectively, an average and a standard deviation of 5.59 \(\pm\) 1.36 in ParAF and 6.20 \(\pm\) 1.08 in PerAF. As shown in Table 6 for the SE and DET, the Mann-Whitney test rejected the null hypothesis in most of the recording places, with particularly low _p_-values in the right superior pulmonary vein (RSPV), while in the right inferior pulmonary vein (RIPV), the null hypothesis was accepted, which suggests the presence of a similar atrial electrophysiological substrate in both AF types. For the AFCL, the _p_-values were always higher than the significance level of 0.05, except for the RSPV. Finally, the statistical tests run for the DF showed no differences between ParAF versus PerAF except in the left superior pulmonary vein (LSPV) and in the posterior free wall of the left atrium (POS). The correlation matrix obtained by averaging the correlation values of the 1, 2, and 4 s length datasets is shown in Figure 4. In particular, a strong negative correlation between the index pairs of the SE-DET and AFCL-DET recorded at the same recording places was observed, while a strong positive correlation appeared between the paired SE-AFCL measured at the same recording place. The application of the correlation matrix filter to 1 and 2 s length datasets removed the indices DF\({}_{\text{LIPV}}\) and entirely removed the indices of the DET and AFCL, due to their strong correlation with the SE. For the 4 s length dataset, the subset of indices kept was SE\({}_{\text{LSPV}}\), SE\({}_{\text{LIPV}}\), SE\({}_{\text{RSPV}}\), SE\({}_{\text{RIPV}}\), SE\({}_{\text{FOS}}\), AFLC\({}_{\text{ANT}}\), DF\({}_{\text{LSPV}}\), DF\({}_{\text{RSPV}}\), DF\({}_{\text{RIPV}}\), DF\({}_{\text{ANT}}\), and DF\({}_{\text{POS}}\).