## 4 Experiments and Results
### Real Case for Fragmentation-Wave Enhancement  
In this experiment we checked the behavior of the previously described methods, but this time applied it to real fragmented cases. The experimental set-up was divided similarly to the earlier approach, in two stages; namely, preprocessing and fragmentation analysis. The preprocessing followed very much the setup described earlier, but for the reader convenience and in an attempt to provide a summarized full picture, it is sketched here again: First, the signals were band-pass filtered in order to reduce noise; Second, baseline wander was removed using cubic spline interpolation; Third, the main peaks were detected using the algorithmic carefully developed in our group for years working in this area [25]; Finally, the beat templates were created for each lead, through statistical filtering, averaging only high-correlated peaks. For more detailed information on the method, the interested reader can see [26]. As a second step, the wave enhancement evaluation differed from previous analysis as we do not benchmark with the corresponding un-fragmented pair, although comparisons is possible but only over control signal and again only in statistical terms. The first proposed method that was conveyed was PCA transformation and we followed the strategy described here after. First, the beat templates were selected according to independence criteria, in other words, we picked the mathematically eight independent leads (I, II, V1, V2, V3, V4, V5 and V6). Then PCA was applied over beat templates, and we selected the three components with lower variance. For the second case, we applied ICA transformation over beat templates, and output components were sorted according to kurtosis. Then, the last four independent components according to their kurtosis were selected. As it can be seen in Panel (c) from Figures 16-20, the fragmentation in PCA appears of two different ways, namely, as a large number of independent peaks Figures 16c and 19c, or as notchs and slurs similar to those ones which appears in fragmented ECG. In ICA cases (Panel (d) from Figures 16-20), the fragmentation waves appear as a high frequency noise inside the QRS window. Figure 16: Example of fragmentation wave enhancement over real fragmented case. (**a**) Beat templates for each lead of real fragmented case. (**b**) Beat templates for each lead of control case. (**c**) Results of the best PCA method for the real fragmented case, in top subpanels and control case in bottom panels. (**d**) Results of the best ICA method for the real fragmented case, in top subpanels and for the control case in bottom panels. Figure 17: Example of fragmentation wave enhancement over real fragmented case. (**a**) Beat templates for each lead of real fragmented case. (**b**) Beat templates for each lead of control case. (**c**) Results of the best PCA method for the real fragmented case, in top subpanels and control case in bottom panels. (**d**) Results of the best ICA method for the real fragmented case, in top subpanels and for the control case in bottom panels. Figure 18: Example of fragmentation wave enhancement over real fragmented case. (**a**) Beat templates for each lead of real fragmented case. (**b**) Beat templates for each lead of control case. (**c**) Results of the best PCA method for the real fragmented case, in top subpanels and control case in bottom panels. (**d**) Results of the best ICA method for the real fragmented case, in top subpanels and for the control case in bottom panels. Figure 19: Example of fragmentation wave enhancement over real fragmented case. (**a**) Beat templates for each lead of real fragmented case. (**b**) Beat templates for each lead of control case. (**c**) Results of the best PCA method for the real fragmented case, in top subpanels and control case in bottom panels. (**d**) Results of the best ICA method for the real fragmented case, in top subpanels and for the control case in bottom panels. Figure 20: Example of fragmentation wave enhancement over real fragmented case.